ukt •7 ( f YALE MEDICAL LIBRARY =fi cn ik == era m = HISTORICAL LIBRARY /cf C 'tye Gift °f " $\ 3J1 mi m Is J The Hissfes Ishara Digitized by the Internet Archive in 2016 https://archive.org/details/systemofanatomyf21wist 7 SYSTEM OF ANATOMY FOR THE USE OF STUDENTS OF MEDICINE . BY CASPAR WISTAR, M. D. PROFESSOR OF ANATOMY IN THE UNIVERSITY OF PENNSYLVANIA. VOLUME II. PHILADELPHIA: PUBLISHED BY THOMAS DOBSON AND SON, AT THE STONE HOUSE, No. 41, SOUTH SECOND STREET. William Fry, Printer. 1817 . District of Pennsylvania, to wit: BE IT REMEMBERED, That on the twelfth day of November, » ‘jt L,.. j n ^j le fol'ty-second year of the independence of the United States ••••».••** America, A. D 1817', Thomas Dobson and Son, of the said dis- trict, have deposited in this office the title of a book, the right, whereof they claim as proprietors, in the words following, to wit: “ A System of Anatomy for the use of Students of Medicine. By Caspar Wis- “ tar, M. D. Professor of Anatomy in the University of Pennsylvania. “ Volume II.” In conformity to the act of the congress of the United States, intituled, “An act for the encouragement of learning, by securing the copies of maps, charts and books, to the authors and proprietors of such copies, during the times therein mentioned.” — And also to the act, entitled, “ An act supplementary to an act, entitled “An act for the encouragement of learning, by securing the copies of maps, charts, and books, to the authors and proprietors of such copies during the times therein mentioned,” and extending the benefits thereof ts the arts of designing, engraving, and etching historical and other prints.” D. CALDWELL, Clerk of the district of Pennsylvania. CONTENTS OF VOL. II. PART VI. OF THE NOSE— THE MOUTH— AND THE THROAT. CHAPTER I. Of the Nose. SECTION I. Page UF the External Nose ----- 2 SECTION II. Of the Cavities of the Nose .... 4 CHAPTER II. Of the Mouth and the Salivary Glands. Of the Mouth - .... 14 Salivary Glands ----- 24 CHAPTER III. Of the Throat. SECTION I. Of the Isthmus of the Fauces - - - -29 SECTION II. Of the Larynx - - - - - - 31 Thyroid Gland - - - * - 36 SECTION III. ©f the Pharynx ------ 3f PART VII. OF THE THORAX. CHAPTER I. Of the general Cavity of the Thorax. SECTION I.. Of the Form of the Cavity of the Thorax 44 IV CONTENTS. SECTION II. Of the Arrangement of the Pleurae Preparation of the Thorax Page 45 47 CHAPTER II. Of the Heart and the Pericardium, and the Great Vessels connected with the Heart. SECTION I. Of the Pericardium ..... 49 SECTION II. Of the Heart - - - - - 50 SECTION III. Of the Aorta, the Pulmonary Artery and Vein, and the Venae Cavae at their commencement 59 CHAPTER III. Of the Trachea and Lungs . SECTION I. Of the Trachea - - - - - - 61 The Black Glands on the Bronchiae - - - 64 SECTION II. Of the Lungs - - - . - 64 Thorax of the Foetus ... - - 67 Physiological Observations, &c. - - - - 70 PART VIII. OP THE ABDOMEN. CHAPTER I. si general view of the Abdomen and Pelvis , and their Contents ; with an Account of the Peritoneum. SECTION I. Construction of the Abdomen - - - - 81 Contents of the Abdomen - - - - - 86 SECTION II. Of the Peritoneum ..... 88 CONTENTS. v Fag« CHAPTER II. Of the QLsofihagusythe Stomach , and the Intestines. SECTION I. Of the (Esophagus - - - - - 93 SECTION II. Of the Stomach - - - - - - 95 Gastric Liquor ..... 1 Q 0 SECTION III. Of the Intestines .... Division of the Intestines - The Small Intestines - The Duodenum ------ Jejunum and Ileon .... The Mesentery - Of the Great Intestines - The Caecum and Colon - The Rectum - The Omentum .... CHAPTER III. Of the Liver, the Pancreas, and the SfUeen. SECTION I. Of the Liver ...... 125 SECTION II. Of the Pancreas - - - . - 139 103 - 108 109 - 110 111 - 113 115 - 116 120 124 SECTION HI. Of the Spleen - - - - - - 141 CHAPTER IV. Of the Urinary Organs , and the Glandule Renales . SECTION I. Of the Glandulae Renales a e 150 SECTION II. Of the Kidneys and Ureters . - 152 SECTION III. Of the Urinary Bladder ... 157 VI CONTENTS. CHAPTER V. Of the Male Organs of Generation . SECTION I. Of the Testicles and their Appendages ... i gg SECTION II. Of the Vesiculse Seminales and the Prostate Gland - 176 SECTION III. Of the Penis - - - - - - 179 CHAPTER VI. Of the Female Organs of Generation* SECTION I. Of the External Parts of Generation - - - 192 SECTION II. Of the Vagina ...... 195 SECTION III. Of the Uterus, the Ovaries, and their appendages - 197 SECTION IV. Of the Bladder and Urethra ----- 205 PART IX. OP THE BLOODVESSELS. CHAPTER I. Of the General Structure and Arrangement of the Bloodvessels. SECTION I. Of the Arteries - - - - - - 217 SECTION II. Of the Veins ...... 224 CHAPTER II. A Particular Account of the Distribution of the Arteries. SECTION I. Of the Aorta, or the Great Trunk of the Arterial System 227 SECTION II. Of the Branches which go off from the Arch of the Aorta 229 The Carotid Arteries ..... 230 The Subclavian Arteries .... 247 CONTENTS. vii Page SECTION III. Of the Branches which go off between the Arch and the Great Bifurcation of the Aorta - - - 262 Bronchial Arteries ... - - ib. CEsophageal Arteries ... - - ib. Inferior Intercostals ... - - 263 Phrenic Arteries - - * 265 Cceliac Artery .... - - ib. Superior Mesenteric Artery - - - 268 Inferior Mesenteric Artery - - 270 Emulgent or Renal Arteries - - 271 Capsular and Adipose Artei’ies - - ib. Spermatic Arteries - - - ib. Lumbar Arteries ... - - 273 Middle Sacral Artery ... - - ib. SECTION IV. Of the Arteries which originate at and below the Great Bifur- cation of the Aorta - - - 273 The Primitive Iliac Arteries - - ib. Internal Iliac Arteries ... - - 274 External Iliac Arteries - . - 279 Femoral Artery ... - - 280 Arteries of the Leg - - - 283 CHAPTER III. Of the particular Distribution of the Veins. SECTION I. Of the Superior, or Descending Vena Cava, and the Veins which communicate with it - - - 291 Vena Azygos .... - - 292 Internal Jugular Veins - - - - - 295 External Jugular Veins ... - - 297 Subclavian Vein - - - . - 298 SECTION II. Of the Inferior Vena Cava, and the Veins connected with it 300 Hepatic Veins .... - - 301 Vena Portarum .... - - 302 Emulgent or Renal Veins - - 303 Spermatic Veins .... - - ib. Lumbar Veins .... - - 304 Middle Sacral Vein - - ■ - - - ib. Primitive Iliac Veins - - - ib CONTENTS. viii Internal Iliac Veins External Iliac Femoral Vein Instances of Peculiar Arrangement of the Veins - Of the Pulmonary Artery and Veins PART X. OF THE NERVES. Nerves of the Brain - Of the Cervical Nerves - - Nerves of the Diaphragm - Brachial Plexus - Nerves of the Arm - The Dorsal Nerves .... Of the Lumbar Nerves ... The Sacral Nerves .... Sciatic Plexus .... Great Sciatic Nerve .... Great Sympathetic Nerve - - Nerves of the Heart .... Nerves of the Abdominal Viscera PART XI. OF THE ABSORBENT VESSELS. CHAPTER I. Of the Absorbents of the Lower Extremities — the Abdomen and the Thorax. SECTION I. The Absorbents of the Lower Extremities - - 366 SECTION II. The Absorbents of the Abdomen and Thorax - - 371 CHAPTER II. Of the Absorbents of the Head and JVeck, of the Ufijier Extremities , and the U/i/ier Part of the Trunk of the Body. SECTION I. Of the Absorbents of the Head and Neck - - 382 SECTION II. Of the Absorbents of the Arm, and the Upper Part of the Trunk 383 - 314 334 - 336 337 - 338 342 - 343 346 - 347 348 - 351 353 - 358 Page 304 305 306 307 308 SYSTEM OF ANATOMY. PART VI. OF THE nose: THE MOUTH: AND THE THROAT. CHAPTER I. OF THE NOSE. THE prominent part of the face, to which the word nose is exclusively applied in ordinary language, is the anterior covering of two cavities which contain the organ of smell- ing- These cavities are formed principally by the upper max- illary and palate bones; and, therefore, to acquire a com- plete idea of them, it is necessary to study these bones, as well as the os ethmoides, the vomer, and the ossa spongi- osa inferiora, which are likewise concerned in their forma- tion. In addition to the description of these bones, in the ac- count of the bones of the head, it will be useful to study the description of the cavities of the nose which follows it. See vol. I, page 53. After thus acquiring a knowledge of the bony structure, the student will be prepared far a description of the softer parts. Vol.IL A 2 ' SECTION I. Of the External Nose. THE superior part of the nose is formed by the ossa nasi, and the nasal processes of the upper maxillary bones, which have been already described; (see vol. I, pages 34 — 36.) but the inferior part, which is composed principally of cartilages, is much more complex in its structure. The orifice, formed by the upper maxillary and nasal bones, is divided by a cartilaginous plate, which is the an- terior and inferior part of the septum, or partition between the two cavities of the nose. The anterior edge of this plate projects beyond the orifice in the bones, and conti- nues in the direction of the suture between the ossa nasi. This edge forms an angle with the lo'wer edge of the same cartilage, which continues from it, in a horizontal direc- tion, until it reaches the lower part of the orifice of the nose, at the junction of the palatine processes of the up- per maxillary bones; where a bony prominence is formed, to which it is firmly united. The upper p^rt of the ante- rior edge of this cartilage, which is in contact with the ossa nasi, is flat, and is continued into two lateral portions that are extended from it, one on each side, and form a part of the nose: these lateral portions are sometimes spoken of as distinct cartilages; but they are really com tinuations of the middle portion or septum. Below the lower edge of these lateral portions are situ- ated the cartilages which form the orifices of the nose, or the nostrils. Of these, there is one of considerable size, and several small fragments, on each side of the septum. Each of the larger cartilages forms a portion of an oval ring, which is placed obliquely on the side of the septum; so that the extremity of the oval points downward and 3 Of the Nose. forward, while the middle part of the oval is directed up- wards and backwards. The sides of this cartilage are flat, and unequal in breadth. The narrowest side is internal, and projects lower down than the cartilaginous septum; so that it is applied to its fellow of the other nostril. The ex- ternal side is broader, and continues backward and up- ward to a considerable distance. The upper and posterior part of this oval ring is defi- cient; but the remainder of the nostril consists of several small pieces of cartilage, which are fixed in a ligamentous membrane that is connected by each of its extremities to the oval cartilage, and thus completes the orifice. The anterior parts of the oval cartilages form the point of the nose; and the ligamentous portions, the alas or lateral parts of the nostrils. When the external integuments and muscles are remo- ved from the lower portion of the nose, so that the internal membrane and these cartilages only remain, the inter- nal membrane will be found attached to the whole bony margin of each orifice, and to each side of the whole ante- rior edge of the middle cartilage, which projects beyond the bones, so that it would close up these openings of the nose, if it were not for the orifices formed by the oval cartilages and the ligament above described; but being attached to one edge only of these cartilages, the orifice formed by them is complete. The internal portions of the oval cartilages being situ- ated without the septum, and applied to each other, they form the external edge of the partition between the nos- trils, or the columna nasi; which is very moveable upon the edge of the middle cartilage. The orifices of the nostrils, thus constructed, are dilated by that portion of the muscle, called Levator Labii Supe- riors Alaque Nasi, which is inserted into the alas nasi. They are drawn down by the depressor labii superioris. 4 Of the Cavities of the Nose. alasque nasi. They are pressed against the septum and the nose by the muscle called Compressor Naris , which has however an opposite effect when its upper extremity is drawn upwards by those fibres of the occipito- frontalis, which descend upon the nose, and are in contact with it. The end of the nose is also occasionally drawn down, by some muscular fibres which descend from it, on the septum of the nose, to the orbicularis oris: they are con- sidered as a portion of this muscle by many anatomists, but were described by Albinus as a separate muscle, and called Nasalis Labii Superioris. When inspiration takes place with great force, the alae nasi would be pressed against the septum if they were not drawn out and dilated by some of the muscles above mentioned. SECTION II. Of the Cavities of the Nose. TO the description of the osseous parts of the nasal cavities in vol. I, page 53, it ought now to be added that the vacuity in the anterior part of the osseous septum is filled up by a cartilaginous plate, connected with the na- sal lamella of the ethmoid bone above, and with the vo- mer below. This plate sends off those lateral portions al- ready described, which form the cartilaginous part of the bridge of the nose. It should also be observed that at the back parts of these cavities are two orifices called the Posterior Nares, which are formed by the palate bones, the vomer, and the body of the sphenoidal bone, and are somewhat oval in figure. Schneiderian Membrane. 5 The nasal cavities, thus constructed, are lined by a pe- culiar membrane, which is called pituitary from its secre- tion of mucus, or Schneiderian after an anatomist who de- scribed it with accuracy.* This membrane is very thick and strong, and abounds with so many bloodvessels, that in the living subject it is of a red colour. It adheres to the bones and septum of the nose like the periosteum, but separates from them more easily. The surface which adheres to the bones has some resemblance to periosteum; while the other surface is soft, spongy, and rather villous. Bichat seems to have consi- dered this membrane as formed of two laminae, viz: peri- osteum, and the proper mucous membrane; but he adds, that it is almost impossible to separate them. It has been supposed that many distinct glandular bo- dies were to be seen in the structure of this membrane by examining the surface next to the bones;f but this opi- nion is adopted by very few of the anatomists of the present day. The texture of the membrane appears to be uniform; and on its surface are a great number of follicles of various sizes, from which flows the mucus of the nose. These follicles appear like pits, made by pushing a pin obliquely into a surface which retains the form of the im- pression. They can be seen very distinctly with a common magnifying glass when the membrane is immersed in wa- ter, both on the septum and on the opposite surface. They are scattered over the membrane without order or regu- larity, except that in a few places they occur so as to form lines of various lengths, from half an inch to an inch. The largest of them are in the lower parts of the cavities. It may be presumed that the secretion of mucus is ef- * Conrad Schneider, a German professor, in a large work , es off from it. The orifice of the urethra is situated ante- riorly at the lowermost part of the bladder. On the low- er surface of the urethra, at its commencement, and on the bottom of the bladder, immediately connected with the urethra, is situated the Prostate Gland., (to be here- after described with the organs of generation,) which is a firm body, that adheres strongly both to the hladder and urethra. This circumstance gives particular firmness and solidity to that part of the bladder. It has also been ob- served, that the bladder is attached firmly to the ossa pubis, at its neck, about the origin of the urethra. E>ch of these circumstances have an effect upon the orifice of the urethra; and when the bladder is opened, and this ori- fice is examined from within, it appears to be kept open by the connexion of the bladder with the prostate, and has been very justly compared to the opening of the neck of a bottle into the great cavity of that vessel.* The orifices of the two ureters are at equal distances from the orifice of the urethra, and form with it the an- gles of a triangle. That part of the internal surface of the bladder which is within this triangular space, is more smooth than the remainder of the same surface, probably in consequence of the adhesion of the bladder to the prostate, and to other parts exterior to it. That part of the bottom of the bladder which is imme- diately behind the triangular space, i§ rather lower than * The late Mr. Lieutaud, and after him the French anatomists of the present day, have described a small tubercle at the lower and posterior part of the orifice of the urethra, which resembles the uvu- la in form It has not been noticed here; and M. Boyer states, that it is often scarcely preceptible. He, however, makes a remark which is very worthy of attention, viz. that it is very subject to enlarge- ment in old people, forming a tumor which impedes the discharge of urine. Sabatier has also made the same observatiou. Ligaments and Vessels of the Bladder • 1 65 this space; and but a small portion of cellular membrane exists between it and the rectum in males, and the va- gina in females. The upper part of the bladder is connected with the umbilicus by means of a ligament, which passes between the peritoneum and the abdominal muscles. This liga- ment consists of three cords. One of these, which is. in the middle, arises from the coats of the bladder, and was, in the foetus, the duct called urachus; the other two, which are connected to the bladder principally by cellular membrane, were originally the umbilical arte- ries.* The middle cord is of a light colour and fibrous structure; it is thickest at the bladder, and gradually di- minishes as it approaches the umbilicus. In a few in- stances it has Leen found to be hollow. In its progress to the umbilicus it becomes more or less blended with the linea alba, or the tendons of the abdominal muscles. The other cords are generally solid. After passing from the umbilicus to the bladder, they continue on the sides of that viscus, and finally terminate at the hypogastric or internal iliac artery. In the very young subject these cords are invested by distinct processes of the peritoneum, but their position is exterior to the peritoneum. As the bladder is situated very near most of the large ramifications of the hypogastric artery in the pdvis, it receives branches from several of them; viz. from the umbilical arteries before they terminate; from the pudic; from the obturators, &.c. These branches ramify in the cellular membrane exterior to the muscular coat, and also in the cellular substance between the muscular and internal coats. It has been conjectured , that their termi- nations in exhalents on the surface of the bladder are re- markably numerous. * See the accounts of these parts in the description of the Abdo- men of the Foetus. 164 General Observations . The veins correspond with the arteries, but they are very numerous on the lower and lateral parts of the blad- der, and by uniting with the veins of the rectum form a remarkable plexus. The Lymphatic Vessels of this organ do not appear more numerous than those of other parts. They pass on each side the bladder in the course of its bloodvessels, and unite with* the larger lymphatics, and the glands which lie* upon the great bloodvessels on the sides of the pelvis. The Nerves of the bladder are derived both from the intercostal nerve and from the nerves of the medulla spi- nalis, which pass off through the sacrum; and therefore the bladder is more affected than the viscera of the abdo- men, by injuries of the medulla spinalis. The action of the muscular fibres of the bladder in expelling urine, and the effect of those fibres which are situated near the orifice of the urethra in retaining it, can be considered with more advantage after the structure of the urethra and the muscles connected with that canal have been described. It has been stated, that the internal coat of the bladder is very sensible; but it may be added, that in consequence of dis- ease about the neck of the bladder, the natural sensibility ap- pears most inordinately increased. When the intensity of pain which accompanies these complaints, the frequent recurrence of paroxysms, and their duration, are taken into view, there seems reason to believe that none of the painful affections of the human race exceed those which arise from certain dis- eases of the bladder. Happily these diseases are not very common. The function of the kidneys is to secrete urine, and that of the bladder to retain it until the proper time for evacuation. The urine may be regarded as an excrementitious fluid, which contains many substances in solution that are constant- ly found in it, and many others that are occasionally in it, which are taken as aliment or medicine, and pass to the blad- der with little, if any, change. The odour of the rose leaf, the colour of rhubarb, &c. are occasionally perceived in urine. The substances constantly found in urine are numerous. General Observations , 165 The chemical account of the subject is so long, that it cannot be detailed here; but the student ought to make himself ac- quainted with it, and he will read with great advantage John- son’s History of Animal Chemistry, vol. 2d, page 363; and also Thompson’s Elements of Chemistry, page 333. 166 CHAPTER V. OF THE MALE ORGANS OF GENERATION. THESE organs consist, 1st, of the Testicles, and their appendages. 2d. Of certain parts denominated the Vasicula Semi- nales and the Prostate Gland, which are situated near the commencement of the urethra, and are subservient to the purposes of generation. 3d. Of the Penis. SECTION I. Of the Testicles and their appendages. THE Testicles are two bodies of a flattened oval form. Each of them has a protuberance on its upper and poste- rior part called Epididymis , and is connected to parts within the cavity of the abdomen by a thick cord, which proceeds to it through the abdominal ring. Each testicle also appears to be contained in a sac, which is suspended by this cord and covered by the common integuments. That portion of the common integuments which forms the external covering of the testicles, is denominated The Scrotum. The skin of the scrotum, although it is very often in a state of corrugation, has the same structure with that on other parts of the body, except that it is rather thinner 167 Structure of the Scrotum. and more delicate. The superior delicacy of this portion of the skin is evinced by the great irritation produced by the application of stimulating substances, and the desqua- mation of the cuticle, which seems to be the effect of ir- ritation. There are many sebaceous follicles in this portion of skin; and after puberty there are often a few long hairs growing out of it, the bulbs df which are often very con- spicuous. There is a small raised line in the middle of this skin, which commences at the root of the penis, and proceeds backwards, dividing it into two equal parts: this line is denominated Raphe. The corrugation which so often takes place in the skin of the scrotum, appears to be occasioned by the contrac- tion of certain fibres, which are in the cellular substance immediately within it. This cellular substance appears to be attached in a particular way to the skin; and it also in- vests each testicle in such a manner, that when they are Withdrawn a cavity is left in it. It has long been observed, that no adipose matter is found in this cellular substance; but it is often distended with water in hydropic diseases. As the contraction and corrugation of the scrotum has been imputed to this substance, it has been examined with particular attention by anatomists, and very different sen- timents have been entertained respecting it. While some dissectors have asserted that muscular fibres could be seen in it, which they have denominated the Dartos Mus- cle; others hav^ said that this substance was simply cellu- lar, and without any muscular fibres. This difference of sentiment may possibly have arisen from the different conditions of this part in different subjects; for in some cases there are appearances w’hich seem to justify the as- sertion that muscular fibres exist in this structure. After the testicles are removed, so as to leave the cel- lular substance connected with the skin, if the scrotum be inverted, and this substance examined' in a strong light, many fibres will appear superadded to the common cellu- 168 Action of the Dart os Muscle. lar structure; and sometimes their colour can be distin- guished to be red. It is not asserted that this will be uniformly the case; but certainly it has often been ob- served in this way. The existence of an organ which possesses the power of contraction, within the skin of the scrotum and con- nected to it, is evinced by the corrugation which takes place when the scrotum is suddenly exposed to cold, after having been very warm. This corrugation occurs in a very sudden and rapid manner, in some cases, in which the wounded scrotum is thus exposed for the purpose of dressing: for example, upon removing an emollient poultice from this part some days after the operation for the cure of hydrops testis, by incision; if the air of the chamber be cool, a motion of the scrotum will take place, almost equal to the peristaltic move- ments of the intestines. The Arteries of the scrotum are derived from two sources. One or two small arteries, which arise from the femoral artery, between Poupart’s ligament and the ori- gin of the profunda, are spent upon it. These are called the external pudic arteries. It also receives some small branches from the internal pudic artery. The Nerves of the scrotum are principally derived from the lumbar nerves. The Spermatic Cord. The cord which proceeds to the testicle through the abdominal ring, appears at first view like a bundle of muscular fibres; but it consists of an artery and veins, with many lymphatic vessels and nerves, and also the excretory duct of the testicle, connected to each other by cellular substance, and covered by an expansion of muscular fibres which are derived from the lower edge of the interna] oblique muscle of the abdomen, and con- Cremaster Muscle. Bloodvessels of the Testicle. 169 tinue from it to the upper part of the testicle. These fibres constitute the Cremaster Muscle . The artery above mentioned is called the Spermatic. It commonly arises from the front of the aorta, very near its fellow, at a small distance below the emulgents: and is not much larger than a crow’s quill. It proceeds downwards behind the peritoneum and before the psoas muscle and ureter. While it is in contact with the psoas muscle, it joins the ramifications of the vein. It after- wards meets the vas deferens, and proceeds through the abdominal ring to the back part of the testis. Before it arrives at the testis it divides into several branches, two of which generally go to the epididymis, and the others penetrate the tunica albuginea on the upper and back of the testicle, and ramify very minutely on the fine membra- nous partitions which exist in that body. In addition to the spermatic artery, there is a small twig from the umbilical branch of the hypogastric, which passes to the spermatic cord along the vas deferens. The branches of the spermatic vein are much larger than those of the artery: several of them proceed from the testicle so as to correspond with the arterial branches; and in addition to these there are many smaller, which also arise from the testicle and epididymis. In their course up the cord they ramify, and again unite, so as to form a considerable plexus, which is called the Corpus Pampiniforme , and constitutes a considerable part of the volume of the spermatic cord. As they proceed upwards they unite into a few larger veins; and finally, on the psoas muscle, they generally form one trunk, which continues upwards so as to unite with the vena cava on the right side and the emulgent vein on the left. Sometimes, but not often, there are several spermatic veins on each side. The Lymphatic Vessels of the testicle are very numer- Vol. II. Y 170 Lymphatics and Nerves of the Spermatic Cord. ous, considering the size of the organ. Six or eight, and sometimes more, large trunks have been injected, run- ning upon the cord, and continuing to the glands on the back part of the abdomen. The Nerves of the testicle are derived from those which supply the viscera of the abdomen, and are to be found in the cord although they can scarcely be traced to the testicle. A small plexus, called the spermatic, is formed by fibres from the renal plexus and from the sympathetic nerve. These fibres accompany the sper- matic vessels, and in all probability enter the body of the testis and the epididymis. The spermatic cord and cremaster muscle receive filaments from the second lumbar nerve. In addition to these vessels, the Fas Deferens, which is much firmer than either of them, is always to be dis- guished in the back part of the cord. They are all covered in front and on the sides by the cremaster muscle, which passes with them from the lower margin of the internal oblique, through the abdo- minal ring, and continues to the upper part of the ex- ternal coat of the testicle, which is a sac apparently con- taining that organ, and upon this sac it is spread out and terminates. The Tunica Vaginalis. The External Coat of the testicle, which is commonly called the Tunica Vaginalis, is a complete sac which in- closes the testicle as the pericardium incloses the heart. It covers the body of the testicle and epididymis, and adheres closely to them. It is then reflected from them so as to form a loose sac, which appears to contain them. The cavity of the tunica vaginalis commonly extends above the body of the testis up the cord, and is oval or pyriform. This sac is so reflected from the body of the 271 Coats of the Testicle . testicle, that there is a place on the upper and back part of that body at which the bloodvessels enter it, without penetrating the sac. It resembles the peritoneum and other serous mem- branes in texture, and is therefore thin and delicate. It always contains a quantity of moisture, sufficient to lu- bricate the surface which it forms. When the tunica vaginalis is laid open, the testicle ap- pears as if it were contained in the posterior part of its cavity. The testicles, as has been already stated, are of a flat- tened oval form. Their position is somewhat oblique, so that their upper extremities look upwards and forwards, their lower extremities downwards and backwards, and their edges present forwards and backwards. The body of the testicle is very firm, in consequence of its inclosure in a very firm coat called Tunica Albugi- nea. Upon the upper and posterior part of it is the pro- tuberant substance, called Epididymis , which is less firm, being exterior to the tunica albuginea. The bloodvessels of the testicle pass into it on the posterior edge, at some distance below the upper end. The Tunica Albuginea , In which the body of the testicle is completely inclos- ed, is firm and dense; and upon this coat its particular form depends. It is of a whitish colour, and has a smooth external surface. It is thick as well as strong, The epi- didymis is exterior to it. It is only perforated by the bloodvessels, lymphatics and nerves, and by the vasa efferentia, which carry out the secretion of the testis. One portion of the tunica vaginalis adheres very closely to it, and the other appears to contain it. The portion which adheres to it is with difficulty separated, but it is a distinct membrane. 172 Form and Connect mis of the Epididymis . The Epididymis Differs in colour from the testicle, being more or less reddish. It commences at the upper and anterior extre- mity of the testicle, and passes down the posterior edge to the lower end. At the commencement the epididymis is somewhat rounded in form, and its upper part, or head, has been called the globus major: as it descends it lessens, and about the middle of the testicle it is flattish. It is firmly attached to the body of the testicle, at the upper end, where the vasa efferentia pass to it; and it is also attached to it below; but at the middle it appears nearly detached from it. It has therefore been compared to an arch resting' with its two extremities on the back of the testis; iti^, however, in contact with it at its middle; but about the middle it only adheres by one of its edges to the body of the testis, and generally by its internal edge. It has a coat which is less firm than the tunica albuginea of the testicle, described on the last page. The tunica vaginalis of the testicle is so reflected as to cover a great part of the epididymis which is not in contact with the testicle, and also those surfaces of the epididymis and testis which are in contact with each other and do not ad- here. The Body of the Testicle. When the tunica albuginea is cut through, and the substance of the testicle examined, it appears to consist of a soft pulpy substance of a yellowish brown colour, which is divided into separate portions by very delicate septa, attached to the internal surface of the tunica albu- ginea at the posterior part of the testicle. After macera- tion, by using a fine needle to detach them from the cel- lular substance, these threads may be drawn out to a great length. In some animals they are larger than in the Tubuli, Septa and Bloodvessels of the Testicle . 173 human species; in them, it is said, they are evidently hol- low, and that very small bloodvessels appear in their coats. When mercury is injected into the vas deferens, or excre- tory duct of the testis, in a retrograde course, it can be perceived in these ducts in the human subject. These delicate septa, or partitions, are united to the in- ternal surface of the tunica albuginea at the posterior part of the testicle, at which place there is a body called Corpus Highmorianum , which has been regarded very dif- ferently by different anatomists. It is a long whitish sub- stance, which extends lengthwise on the posterior part of the testis; and was supposed by Haller to resemble one of the salivary ducts. It is now, however, generally agreed to be of a cellular structure, and to contain and support the ducts which pass from the substance of the testicle to the epididymis. The bloodvessels pass into the body of the testicle upon these septa, and are continued from them to the fila- ments or tubes of which the body of the testicle consists. As in some animals bloodvessels are distinguished on these tubes, there is the greatest reason to believe that a direct communication subsists between them, without the intervention of any other structure, no other structure hav- ing been discovered; but at the same time it ought to be observed, that these tubes have not yet been injected from the bloodvessels. Some ingenious anatomists have injected the artery going to the testicle so successfully, that the injection has passed from it into the veins coming out of the testicle; but it is not now said by any of them, that they have filled the tubes in this manner. Mercury will pass into these vessels from the excre- tory duct of the testicle; and by means of an injection in that way, the structure of the testicle can be unravelled. This structure is as follows: The cavity formed by the tunica albuginea is divided into a number of apartments by the very thin septa, or partitions, above mentioned. From 174 Structure of the Testicle and Epididymis . the filamentary or tubular matter which fills each of these chambers, proceeds a number of small tubes or vessels, which observe a straight course; they are therefore called Vasa Recta. These vasa recta unite with each other and form a network on the back of the testis, within the tu- nica albuginea, which is called Rete Testis. From this network other vessels, from twelve to eighteen in number, denominated Vasa Ejferentia , proceed through the albugi- nea to the epididymis. These vessels are convoluted in such a manner as to form bundles of a conical form, which are called Coni Vasculosi. The number of these corres- ponds with the number of the vasa efferentia, and they compose about one third of the epididymis, viz. all the upper part of it. The single tubes which form each of these cones, successively unite into one duct, which is convoluted so as to form all the remainder of the epidi- dymis. The lower part of the epididymis is turned up- wards on the back of the testicle, the tube gradually en- larges and is less convoluted, and finally becomes straight: it then takes the name of V is Deferens , and continues on the back of the testicle to the spermatic cord.* A small solitary vessel or duct, has been observed by Haller, Monro, and several other anatomists, to proceed from the upper part of the epididymis: sometimes it * De Graff appears to have been the first anatomist who made much progress in the successful investigation of the structure of the testicle; and Haller ought to be mentioned next to him, on account of the plate exhibiting this structure, and the explanation of it, which he published in the Philosophical Transactions of London, for 1749. This plate has been republished by the second Monro, in the Lite- rary and Physical Essays of Edinburgh, and also in his Inaugural Thesis. Haller has likewise republished it in his Opera Minora- It represents not only the vasa efferentia and the cones formed by their convolutions, but also the rete testis and the vasa recta. Haller could inject no further than this; but Monro and Hunter soon after succeeded so as to fill a considerable portion of the body of the tes- ticle with mercury, injected by the vas deferens. 175 Course of the Vas Deferens . unites to the epididymis below, and sometimes it pro- ceeds upwards. The nature of this vessel has not been ascertained with certainty. The Fas Deferens Is a very firm tube about two lines in diameter, which is not perfectly cylindrical exteriorly, although the cavity formed by it is so. This cavity is so small in diameter, that it will only admit a fine bristle. The coats of the duct have, of course, a considerable thickness. The in- ternal coat forms a soft surface, analogous to that of the mucous membranes: the external is firm, and its texture resembles that of cartilage. Owing to the small size of the cavity, the internal coat has not been separated from the external. It passes upwards in the posterior part of the spermatic cord, and continues with it through the abdominal ring, under and exterior to the peritoneum; soon after this it leaves the cord and dips down into the cavity of the pel- vis, forming a curve on the side of the bladder, and pro- ceeding backwards, downwards and inwards. In this course it crosses the ureter, and passes between it and the bladder. On the lower part of the bladder the two vasa deferentia approach each other so gradually, that they ap- pear to be nearly parallel. They proceed forward be- tween the vesiculse seminales, which are two bodies irre- gularly convoluted, that are placed in a converging posi- tion with respect to each other, and communicate with the vasa deferentia. The vasa deferentia finally terminate almost in contact with each other in the posterior part of the prostate gland, where they perforate the urethra. At the distance of about two inches and a half from their termination they enlarge in diameter, and become some- what convoluted. At the posterior margin of the prostate they come in contact with the anterior extremities of the 176 Structure of the Vesicula Seminales. vesiculse seminales, and unite with them. After this union they diminish in size, and become conical; and passing* a short distance through the substance of the prostate, during which they approach each other more rapidly, they penetrate the urethra, so as to open in it on each side o 1 a small tubercle, called the Caput Gallinaginis y soon to be described. SECTION II. Of the V esicula Seminales and the Prostate Gland . THE Vesicula Seminales are two bodies of a whitish colour, and irregular form, being broad and flat at their posterior extremities, and terminating in a point at the other. Their surfaces are so convoluted, that they have been compared to those of the brain. They are situated between the rectum and bladder, and are connected to each by cellular membrane. When the vesiculae seminales are laid open by an in- cision, they appear to consist of cells of a considerable size, irregularly arranged; but when they are carefully examined exteriorly, and the cellular membrane about them is detached and divided, they appear to be formed by a tube of rather more than two lines diameter, and se- veral inches in length, which terminates, like the cascum, in a closed extremity. From this tube proceed from ten to fifteen short branches, which are closed in the same man- ner. All these tubes are convoluted so as to assume the form of the vesicula: seminales above described; and they are fixed in this convoluted state by cellular membrane, which firmly connects their different parts to each other. It is obvious, that tubes thus convoluted, when cut into, will exhibit the appearance of cells, as in the present in- stance. Function of the Vesiculce Seminales. 177 This convoluted tube, composing the vesiculae semi- nales, terminates in a very short duct, which is nearly of the same diameter with the vas deferens, and this duct joins the vas deferens so as to form an acute angle. From the union of the vesiculae seminales with the vas deferens on each side, a canal, which seems to be the continuation of the vas deferens, proceeds through part of the prostate to the urethra, which it perforates. These canals are from eight to twelve lines in length; they are conical in form, their largest extremity being equal to the vas deferens at that part. If air or any other fluid be injected through the vas de- ferens into the urethra, it will pass at the same time into the vesiculce seminales, and distend them. It has been ob- served, that a fluid passes in this manner much more readily from the vasa deferentia into the vesiculae semi- nales, than it does from these last mentioned organs into the duct. These organs were generally regarded as reservoirs of semen, and analogous to the gall bladder in their func- tions, until the late Mr. J. Hunter published his opinion that they were not intended to contain semen, but to se- crete a peculiar mucus subservient to the purposes of ge- neration. He states the following facts in support of his opinion. A fluid, very different from semen, is found after death in the vesiculae seminales. In persons who have lost one testicle, a considerable time before death, the vesiculae seminales on each side are equally distended with this peculiar fluid. The sensation arising from redundance of the secretion of the testes, is referred to the testes, and not to the vesi- culae seminales. In some animals, there is no connection between the vasa deferentia and the vesiculae seminales. Vol. II. Z 178 Prostate Gland. See Observations on certain parts of the Animal Eco- nomy, by John Hunter. The Prostate Gland Is situated on the under and posterior part of the neck of the bladder, so as to surround the lower side of the urethra. Its form has some resemblance to that of the chesnut, but it has a notch on the basis like that of the figure of the heart on playing cards, and it is much larger than the chesnut of this part of America. The basis of this body is posterior, and its apex anterior; its position is oblique, between the rectum and the symphisis pubis. On the upper surface is the groove occupied by the urethra; below there is in some cases a small furrow, which, in addition to the notch above, gives to the gland an appear- ance of being divided into two lobes. It adheres to the urethra and neck of the bladder. Its consistence is very firm and dense, resembling the indu- ration of scirrhus rather more than the ordinary texture of glands. This gland receives small branches from the neighbour- ing bloodvessels, and has no artery of considerable size exclusively appropriated to it. As it lies in close contact with the urethra, the ducts which pass between it and the urethra are not to be seen separate from these bodies; but ducts can be seen in the substance of the gland, which perforate the urethra, and open on the sides of the caput gallinaginis to the number of five or six on each side. By pressure a small quantity of a whitish fluid can be forced from these orifices, which is rather viscid, and coagulable in alcohol. The particular use of this fluid is not knowji. Penis. 179 SECTION III. Of the Penis. THE penis, when detached from the bladder, and the bones, to which it is connected, and divested of the skin which covers it, is an oblong body, which is rounded at one extremity and bifurcated at the other. It is composed of three parts, viz. two oblong bodies, called Corpora Cavernosa, which, at their commence- ment, form the bifurcated portions, and then unite to com- pose the body of the organ; and a third part, of a spongy texture, which is connected to these bodies where they unite to each other, on the under side, and continues at- tached to them during the whole extent of their union, terminating in an expanded head which covers the ante- rior extremities of the corpora cavernosa. The urethra passes from the neck of the bladder, on the under side of the penis, to its anterior extremity, invested by this third body, which is therefore called Corpus Spongiosum Ure- thra. The two bifurcated extremities are attached each of them to one of the crura of the pubis and ischium; and they unite to form the body of the penis immediately an- terior to the symphisis pubis, to which the lower part of it is also attached; so that the penis is firmly connected to the middle of the anterior part of the pelvis. The urethra proceeds from the neck of the bladder, between the crura of the ischium and pubis and the crura of the penis, to join the body of the penis at its commencement, and near this place its connection with the corpus spongiosum be- gins; so that there is a small portion of the urethra between the neck of the bladder and the commencement of the corpus spongiosum, which is not covered by the corpus ISO Corpora Cavernosa Penis. spongiosum. This is called the membranous part of the urethra. The penis, therefore, consists of two oblong bodies of a cellular structure, which originate separately, but unite together to form it; and of the urethra, which joins these bodies immediately after their union, and is invested by a spongy covering, which by its expansion forms the ante- rior extremity not only of the urethra but of the whole penis. These three bodies, thus arranged and connected, are covered by cellular membrane and skin in a manner to be hereafter described. The Corpora Cavernosa , Which compose the body of the penis, are two irre- gular cylinders, that are formed by a thick dense elastic membrane, of a whitish ligamentous appearance and great firmness. They are filled with a substance of a cellular structure, which is occasionally distended with blood. The crura of these cylindrical bodies, which are attached to the crura of the ischium and pubis, are small and pointed at the commencement, and are united to the periosteum of the bones. In their progress upwards they enlarge, and at the symphisis of the pubis they unite so as to form one oblong body, which retains the appearance of a union of two cylinders applied to each other lengthways; for above there is a superficial groove passing in that direction, which is occupied by a large vein; and below there is a much deeper groove, in which the urethra is placed. Between these grooves is a septum which divides one side of the penis from the other. It appears to proceed from the strong membrane which forms the penis, and is composed of bundles of fibres, which pass from one groove of the penis to the other, with many intervals between them, through which blood or injection passes very freely. Sometimes these bundles 181 Cells of the Corpora Cavernosa . of fibres, with their intervals, are so regularly arranged, that they have been compared to the teeth of a comb. This septum extends from the union of the two crura to their termination. Each of these cylinders is penetrated by the main branch of the pudic artery, which is about equal in size to a crow’s quill. These arteries enter the corpora caver- nosa near their union, and continue through their whol e extent, sending off branches in their course: the turges- cence and erection of the penis is unquestionably pro- duced by the blood which flows through these vessels into the penis. The interior structure of the penis, when examined in the recent subject, is of a soft spongy nature, and seems stained with blood. If any fluid be injected through the arteries this substance appears cellular, and may be com- pletely distended by it. When air is injected, and the structure becomes dry, the penis may be laid open; the cellular structure then appears as if formed by a number of laminae and of filaments, which proceed from one part of the internal surface of the penis to another, and form irregular cells. It has been compared to the lattice-work in the interior of bones; and it is suggested by M. Roux, that the fibres of which the structure consists resemble those of the strong elastic coat of the penis.* If these cells are filled with coloured wax, injected by the artery, and the animal substance is then destroyed by placing the preparation in a corroding liquor, the wax which remain^ shows that the membranes forming the cells are very thin. These cells communicate freely with each other; and therefore, if a pipe be passed through the strong coat of the penis, the whole of them can be filled from it by the ordinary process of injection. * The late J. Hunter thought they were muscular. 182 Corpus Spongiosum. Bulb . The Urethra Is a membranous canal, which extends from the neck of the bladder to the orifice at the extremity of the penis; and for a very great part of its length is invested by a spongy structure, called the corpus spongiosum urethrae. It proceeds from the neck of the bladder along a groove in the upper part of the prostate; from the prostate it con- tinues between the crura of the penis until their junction: it then occupies the great groove formed by the corpora cavernosa on the lower side of the penis, and continues to the orifice above mentioned. At a small distance from the prostate gland the spongy substance which invests it commences, and continues to its termination. After this spongy substance has arrived at the termination of the corpora cavernosa, it expands and forms a body of a par- ticular figure which covers the extremities of the corpora cavernosa, and is denominated the Gians Penis. The Corpus Spongiosum begins at the distance of eight or ten lines from the anterior part of the prostate. It is much larger at its commencement than at any other part except the glans, and this enlarged part is called the Bulb. It surrounds' the whole of the urethra, and with the ex- ception of the bulb and the glans penis, is of a cylindrical figure. It is formed by a membrane which has some re- semblance to the coat of the penis, but is much thinner, and by a peculiar spongy substance, which occupies the space between the internal surface of this membrane and the external surface of the canal of the urethra. The membrane and the spongy substance, form a coat to the urethra,- which, with the exception of the enlargement be- fore mentioned, is about two lines thick. It is situated in the groove on the lower side of the penis, and its coat adheres firmly to the coat of the penis. The Bulb , or first enlargement of the corpus spongio- sum, is oblong, and rather oval inform; it is marked by a 183 Structure of the Corpus Spongiosum. longitudinal depression in the middle, which is very su- perficial. It consists entirely of the spongy substance above mentioned. The Gians Penis is also composed of the same spongy substance, but the coat which covers it is more thin and delicate than that of the other parts of the urethra. The lower surface of the glans is fitted to the extremities of the corpora cavernosa, but it is broader than the corpora cavernosa, and therefore projects over them on the upper and lateral parts of the surface of the penis. The edge of the prominent part is regularly rounded, and is denomi- nated the Corona Glandis. Several small arteries pass to this spongy structure. The pudic artery, as it passes on each side to the corpora ca- vernosa, sends a branch to the bulb of the urethra. The same vessel in the substance of the penis, also sends branches to the urethra: and the artery on the back of the penis terminates in small branches, which penetrate the substance of the glans. By these vessels blood is carried to the spongy sub- stance of the urethra, which is occasionally distended in the same manner that the cavernous bodies of the penis are distended during the erection of that organ. But the cellular structure of this organ is not so unequivocal as that of the penis; for if it be injected with coloured wax, and corroded in the usual manner, the injected matter will exhibit an appearance which has the strongest resem- blance to a convoluted vessel, like the vas deferens in the epididymis. The Canal of the Urethra , Which conveys the urine from the bladder, is a very important part of the urinary organs. It consists of a vas- cular membrane with a smooth surface, which is perfo- rated by the orifices of many mucous follicles, some of 184 Internal Surface of the Urethra . which are of considerable size. It is extremely sensible, and has so much power of contraction, that some persons have supposed muscular fibres to exist in its structure. It is differently circumstanced in different parts of its course. While surrounded with the prostate it adheres firmly to that body, seeming to be supported by it; and here its diameter is larger than it is farther forward. On the lower or posterior side of this portion of the urethra, is an oblong eminence, called Verwnontanum , or Caput Gallinaginis, which commences at the orifice of the ure- thra, and continues throughout the whole portion that is surrounded by the prostate gland, terminating at the point of that body. The posterior extremity of this tu- bercle begins abruptly, and soons becomes thick and large; anteriorly it gradually diminishes to a line, which is sometimes preceptible for a considerable distance in the urethra, in a straight forward direction. In the upper edge or top of this body is a groove, which is pro- duced by a mucous follicle; on thp lateral surfaces, ante- rior to the middle, are the orifices of the common ducts of the vesiculae seminales and vasa deferentia (see page 176, 7,) which are sufficiently large to receive a thick bristle. Near these, on each side, are five or six smaller orifices of the excretory ducts of the prostate gland. At a small distance before the caput gallinaginis are the open- ings of two ducts, one on each side, that lead to small glandular bodies called Cowper's glands, which are situa- ted on each side of the urethra below the bulb, but are covered by the accelerator urinae muscle. The diameter of the urethra lessens after it leaves the prostate. That portion of the canal which is between this gland and the bulb, without investment, and there- fore called the membranous part, is the smallest in dia- meter. After it is invested with the spongy substance it has a small enlargement, and then continues nearly of one 185 Mucous Ducts of the Urethra. size until it arrives near the glans penis, when it again enlarges and alters its form, being no longer cylindrical but flattened. Its broad surfaces have now a lateral aspect. From the bulb of the corpus spongiosum to this last enlargement, the appearance of the inner surface of the urethra is uniform. The membrane is thin and delicate, and in a healthy subject, who has been free from disease of these parts, is of a whitish colour; but bloodvessels are very perceptible in it. When it is relaxed, it appears to be thrown into longitudinal wrinkles; but it admits of considerable extension, being somewhat elastic: when extended, its surface appears smooth, as if it were cover- ed with an epithelium. Throughout the whole extent of this part of the urethra, are the orifices of a great many mucous ducts or sinuses, which pass obliquely back- wards from the surface. Many of these are so small that they cannot be penetrated by a bristle, or probe of that size; but some are larger. It has not been observed that any glandular body immediately surrounds them, al- though they secrete the mucus with which the urethra is lubricated. On the lower side of the urethra, near the commencement of the glans penis, there is one or more of them, so large that their orifices sometimes admit the point of a small bougie. These organs, when inflamed, secrete the puriform discharge which takes place in gonorrhoea. In a natural state they produce the mucus which is constantly spread over the surface of the urethra, to defend it from the acri- mony of the urine, and which passes away with that fluid unperceived. The surface of the urethra is endued with great sensi- bility, and is therefore liable to great irritation from con- tact with any rough body or any acrid substance. Irri- tation, thus excited, induces a state of contraction, which is particularly remarkable, as no muscular fibres are to be seen in its structure. When a bougie has been passed Vol. II. 2 A 186 Contractile Power of the Urethra. into the urethra for a considerable distance, if it cannot proceed the whole way, it sometimes happens that the instrument will be discharged by a steady uniform mo- tion, which seems to proceed from a progressive con- traction of the urethra, beginning very low down. At particular times, after the urethra has been much irritat- ed, it will not receive a bougie, although at other times a bougie of equal size may be passed to the bladder without opposition. This cannot depend upon that elas- ticity which was noticed before. Upon the two crura of the penis, or the beginning of the corpora cavernosa, are fixed the muscles called Erectores Penis , which are described in the first volume.* These muscles cover the crura of the penis from their origin to their junction, and not only compress them, but also in- fluence the motion of the penis when it is distended. The bulb of the urethra is covered by a muscular coat, called the Accelerator Urinee ,* which has the effect of driving forwards any fluid contained in the cavity of the urethra, and also of giving the same direction to the blood in that part of the corpus spongiosum. There is also the Transversus Ferine i on each side, that passes trans- versely from the tuberosity of the ischium to the bulb of the urethra. Finally the lower part of the sphincter ani muscle, which is nearly eliptical in form, is inserted by its anterior point into the muscular covering of the bulb of the urethra. Upon removing the integuments, these muscles are in view; and the course of the urethra from the bladder is concealed, particularly by the anterior point of the sphincter ani. When the sphincter ani is dis- sected away from its anterior connections, and the cel- lular and adipose substance, which is sometimes very abundant, is also removed, the lower surface of the * See description of “ Muscles about the Mule Organs of Gene- ration Vol. I. Part II. Chap. II. 187 Integuments of the Penis. membranous part of the urethra may be brought into view, as it proceeds from the prostate gland to the bulb of the corpus spongiosum.* When the accelerator urinae is removed from the bulb of the urethra, there will appear two bodies, which have some resemblance to flattened peas. They lie one on each side of the urethra, and communicate with its cavity by means of a duct, which is from one third to half an inch in length. These are Cowper’s glands. The penis is connected to the symphysis pubis by a ligamentous substance, which proceeds from the back or upper surface of the organ to the anterior part of the symphysis, and connects these parts firmly to each other. Thus constructed, of the corpora cavernosa and the urethra with its corpus spongiosum, and attached to the pelvis as above mentioned, the penis is invested with its integuments in the following manner. Integuments of the Penis. The glans penis, the structure of which has been al- ready desctibed, is covered by a continuation of the skin, which appears altered in its texture so as to resemble in some respects the skin of the lips, and in like manner is covered by a delicate production of cuticle. Around the corona of the glans, especially on its upper part, there are whitish tubercles, which are of different sizes in different persons, but always very small. The skin adheres firmly to the whole extent of the corona of the glans, and is very delicate in its structure as it con- * The natural situation of the membranous part of the urethra, and of the prostate gland, as well as their relative position with respect to the sphincter ani, rectum, &c. can be best studied by a la- teral view of the contents of the pelvis; which is to be obtained by removing carefully one of the ossa innominata, and dissecting the parts which were inclosed by it. 188 The Prepuce. tinues from the glans upon the body of the penis; but it gradually changes, so as to assume the appearance and structure of common skin, and continues in this state over the penis. The adhesion of the skin to the ligament- ous coat of the corpora cavernosa also becomes more loose, owing to the quantity and texture of the cellular substance which connects them. The skin thus connect- ed to the penis, has commonly more length than that or- gan, even in its extended state. In consequence of this greater length, and of its adhering firmly around the co- rona glandis, it necessarily forms a circular fold or plait, which varies in size according to the length of the skin. This fold is generally situated at the commencement of the firm attachment of the skin to the body of the penis, or around the glans; but it may be formed any where upon the body of the penis by artificial management. This duplicature, or fold of the skin, when it takes place so as to cover the glans, is called the Prepuce; and the skin which is very tender and delicate for some dis- tance from the glans, forms that surface of the prepuce which is in contact with the glans when it covers that body. There is also a small fold of the skin, which is longi- tudinal in its direction, that commences at the orifice of the urethra, and extends backwards, on the lower sur- face of the penis. It is unvarying in its position, and is called the Frenum. It is a general observation, that adepts is not found in the cellular substance which connects the skin to the body of the penis; but this cellular substance is distended with water in some hydropic cases. From the skin immediately below the glans, and from small follicles on each side of the frenum, is secreted an unctuous fluid, which, when allowed to continue, be- comes inspissated, and acquires a caseous consistence and colour, as well as a peculiar odour. It sometimes Bloodvessels and Absorbents of the Penis-. 189 also acquires an acrimony which produces inflammation of the surface with which it is in contact, as well as the copious secretion of a puriform fluid. The distribution of the pudic artery in the penis, has already been mentioned; and a further account of its ori- gin and progress to its destination, will be found in the general account of the arteries. Sometimes small branches of the external pudic arteries, which originate from the femoral, are extended to the penis; and it has been as- serted, that branches of the middle hasmorrhoidal artery have also been found there, but this does not often occur. The Feins of the penis are of two kinds: those which originate in the corpora cavernosa, accompany the cor- responding branches of the pudic artery, but communi- cate more or less with the plexus of veins on the lower and lateral part of the bladder. These is also a great vein which occupies the groove on the back of the penis, be- tween the corpora cavernosa, that appears particularly appropriated to the corpus spongiosum urethras; for it originates in the glans penis, and receives branches from the urethra as it proceeds backwards. There are often two of these veins, one in the groove and the other more su- perficial: they generally unite near the root of the penis. The common trunk then passes between the body of the penis and the symphysis pubis, and terminates in a plexus of veins at the neck of the bladder, which is connected to the plexus above mentioned on the lower and lateral parts of the same viscus. The Absorbent Vessels of the penis take two different directions on each side. Those which arise from the in- teguments generally, unite so as to form a few trunks on the back of the penis, which divide near the root of the organ, and proceed to the glands of the groin. Those which originate from the interior parts of the penis, ac- company the bloodvessels, and terminate in the plexus of lymphatics in the pelvis. 190 Nerves. — General Observations. It ought to be noted, that the superficial lymphatics generally enter the upper inguinal glands. The Nerves of the penis are principally derived from the lower sacral nerves, which unite in the plexus that forms the great ischiatic. From these nerves a branch on each side originates, which passes, like the pudic artery, between the sacro-sciatic ligaments. In this course it di- vides into two branches, one of which passes below to the muscles of the penis and urethra, and to the contiguous parts; and some of its branches seem finally to terminate in the dartos: the other branch proceeds along the crura of the pubis and ischium, and passing between the sym- physis pubis and the body of the penis, arrives at the upper surface or dorsum of the penis, along which it con- tinues on the outside of the arteries to the glans, in which it terminates. In this course it sends off several branches, some of which terminate in the integuments of the penis. After an examination of the relative situation of the mus- cles and bloodvessels of the male organs of generation, there appears reason to doubt, whether the erection of the penis can be referred to pressure upon the veins which return from that organ. — Albinus has written on this subject. See Academicarum Annotationum, lib. ii. caput xviii. Haller has also considered it, and stated the opinions of stveral anatomists, in his Elementa Phy- siologic, tom. vii. page 555. The manner in which the urine is confined in the bladder does not appear to be clearly understood. The con- nexion of the neck of the bladder with the prostate, and the appearance of the contiguous parts of the blad- der, do not render it probable that these parts act like a sphincter. The late J. Hunter, who paid great atten- tion to the functions of these organs, was very derid- ed in his opinion that the contraction of the urethra pro- duced the effect of a sphincter of the bladder. He has published some very ingenious observations respecting the manner in which urine is discharged from the blad- General Observations. 191 der, in his Treatise on the Venereal Disease, part III. chapter IX. Mr. Hunter also long since asserted, that the vascular convoluted appearance of the corpus spongiosum urethrae was more distinct in the horse than the man. In the fifth volume of the Le^ns d’Anatomie Comparee of Cuvier, the very learned and ingenious author confirms the de- claration of Hunter, respecting the vascular convolu- tions of the corpus spongiosum of the horse. He states, that the corpora cavernosa of the penis of the elephant appear to be filled in a great degree with the ramifica- tions of veins, which communicate with each other by such large and frequent anastomoses, that they have a cellular appearance. A similar structure exists in the horse, camel, bullock, deer, &c. and in them all these communicating branches can be distinguished from those which extend the whole length of the penis. The corpus spongiosum urethrae, according to M. Cuvier, is constructed in a similar manner. From these facts he is induced to believe that this structure pervades the whole class of mammalia. 192 CHAPTER VI. OF THE FEMALE ORGANS OF GENERATION. THE female organs of generation consist of the Uterus and Ovaries , with their appendages; and of the Vagina , with the structure which surrounds its external orifice. The uterus is situated in the pelvis, between the bladder and rectum; and the ovaries are on each side of it. The vagina is a very large membranous canal, which passes from tl>e uretus downwards and forwards, also between the bladder and rectum, and opens externally. Connected with the orifice of the vagina ar<^ several bo- dies, which are called the external parts of generation , in order to distinguish them from the uterus and ovaries, and their appendages, and also from the canal of the vagi- na; which are called the internal parts. The bladder of urine lies above and in contact with the vagina: the urethra is also intimately connected with it. The description of the bladder and urethra is therefore placed at the end of this chapter. SECTION I. Of the External Parts of Generation. The adipose membrane, immediately anterior to the symphysis pubis, and on each side of it, form a conside- rable prominence in females, which, at the age of puber- ty, is covered with hair, as in males. This prominence is denominated the Mons Veneris. Labia Externa. — Clitoris. 193 The exterior orifice commences immediately below this. On each side of this orifice is a prominence con- tinued from the mons veneris, which is largest above, and gradually diminishes as it descends. These prominences have some hair upon them. They are called the Labia Externa. Their junction below is denominated the Four - chette. The space between the place of their junction and the anus is rather more than an inch in extent, and is de- nominated the Perineum. As the skin which forms the labia is continued inter- nally, it becomes more thin and soft, and is covered by a more delicate cuticle. It is also more or less florid, and secretes a peculiar mucus. In the upper angle, formed by the labia externa, is the upper extremity and glans of the clitoris. The Clitoris is a body which has a very strong resem- blance to the penis, but there is no urethra attached to it. It has two crura of considerable length, which originate, like those of the penis, from the crura of the pubis and ischium, and unite at the symphysis of the pubis so as to form a body, which is not much more than an inch in length, and is broad in proportion. The extremity of this organ, called the Gians of the Clitoris, forms a small tubercle, which is covered above and on the sides by a small plait or fold of the skin, denominated the Prepuce. These parts are lubricated by a secretion similar to that which is observed round the glans penis. The crura of the clitoris have muscles similar to the erectores penis. The interior structure of the Clitoris is very similar to that of the corpora cavernosa of the penis, or the corpus spongiosum of the urethra. It appears con- structed for a similar distention, and is endued with the same sensibility as the penis. The two lateral parts are also separated from each other by a septum, resembling that of the penis. It is united to the symphysis pubis by a ligament. Vol. II. 2 B 194 JVympha. — Hymen. The Prepuce of the clitoris has a semicircular form: below its extremities two folds or plaits commence, one on each side, which are situated obliquely with respect to each other, so as to form an angle. These folds are denominated the JVymphte. The Nymplice extend from the clitoris downwards nearly as far as the middle of the orifice of the vagina. They are situated within the external labia, and are formed by the skin after it has become more delicate in its texture. Their surface however is often somewhat corrugated. There are many bloodvessels in their inter- nal structure, and it is supposed they are occasionally somewhat tumid. They are fiat, and their exterior edge is convex: so that they are narrow at their extremities, and broad in the middle. Their breadth is very variable, and in some instances is great. In a majority of cases it is equal to one fourth of their length. Their colour in young subjects is of a bright red; in women advanced in years and who have had many children, they are of a brown red, and sometimes of a dark colour. The use of these parts is not very evident. They have been supposed to regulate the course of the urine as it flows from the urethra, but their effect in this respect is not great. They have also been supposed to favour the necess. ry enlargement of the parts in parturition. The orifice of the urethra is situated about an inch and one quarter further inward than the clitoris. It is often rather less than the diameter of the urethra, and is some- what protuberant. The orifices of mucous ducts are to be perceived around it. The orifice of the urethra is at the commencement of the canal of the vagina. Immediately within this orifice is situated the membrane denominated Hymen . The Hymen is an incomplete septum, made by a fold or duplicature of the membrane which forms the surface contiguous to it. Sometimes it is circular, with an aper- 195 The Vagina. ture in the center. Sometimes it has a resemblance to the crescent, the aperture being at the upper part of it. The hymen has frequently been found without a perforation, and has therefore prevented the discharge of the men- strual evacuation. It is generally ruptured in the first in- tercourse of the sexes; and some small tubercles, which are found on the surface of the vagina near the spot where it was situated, are supposed to be the remains of it. These tubercles are called Carunculce Myrtijormes. SECTION II. Of the Vagina. THE canal of the vagina, commencing at the hymen and the orifice of the urethra, is rather more narrow at its beginning than it is, further inward. From this place it extends backwards and upwards, and partakes in a small degree of the curve of the rectum: while the bladder, which is above it, and rests upon it, increases the curva- ture of the anterior part. It is much larger in women who have had children than in those who have not. The membrane which lines the vagina resembles, to a certain degree, the membranes which secrete mucus in different parts of the body. Its surface appears to consist of very small papillae; and at the anterior extremity of the vagina it forms a great number of rugae, which are ar- ranged in a transverse direction, both on the part of the vagina connected to the bladder, and on that which is connected to the rectum, while the lateral parts of the va- gina are smooth. These rugae are most prominent in the middle; so that a raised line appears to pass through them at right angles, This line extends from without inwards. The rugae on the part next to the bladder are the strongest. 196 Corpora Cavernosa. — Sphincter Vagina \ This arrangement of the surface of the vagina does not extend beyond the external half of the canal: on the in- ternal half part, or that nearest the uterus, the surface is smooth. The rugae are considerably diminished in tvomen who have had children. Throughout this surface are to be seen, in some cases with the naked eye, the orifices of mucous follicles or ducts, which occasionally discharge considerable quanti- ties of mucus. Exterior to this lining membrane of the vagina is a dense cellular structure, which has not yet been com- pletely investigated: it is of a lightish colour, and has some resemblance to the texture of the body of the ute- rus. It is very vascular, and appears to be of a fibrous structure. It may be very much distended, and seems to have a contractile power. At the anterior extremity of the vagina, on each side of it, there is, superadded to this, a cellular or vascular substance, from eight lines to an inch in breadth; which, when cut into, resembles the corpora cavernosa, or the corpus spongiosum of the penis. These bodies com- mence near the body of the clitoris, and extend down- wards on each side of the vagina. They have been called Plexus Ret ef or mis, and Corpora Cavernosa V igina, and are supposed to be occasionally distended with blood, like the clitoris and penis. These corpora cavernosa are covered by muscular fi- bres, which pass over them on each side from the sphinc- ter ani to the body of the clitoris; to each of which organs they are attached. These fibres constitute the sphincter vaginae muscle, and contract the diameter of the vagina at the place where they are situated. The transversus perinei muscles also exist in the fe- male. They pass from the tuberosities of the ischia, and are inserted into ^ dense whitish substance in the perine- Unimpregnated Uterus. 197 um, to which the anterior extremity of the sphincter ani is likewise attached. The vagina is in contact with the rectum behind; the bladder lies upon it and anterior to it. A small portion of peritoneum, to be reflected to the rectum, is continued from the uterus upon the posterior part of it. The lateral portions of it are invested with cellular substance. The anterior extremity of the uterus, which is called the Os Tincse, projects^nto it from above. SECTION III. Of the Uterus , the Ovaries and their Appendages. The Uterus HAS been compared to a pear with a long neck. There is of course a considerable difference between the body and neck; the first being twice as broad as the last. Each of these parts is somewhat flattened. In subjects of mature age, who have never been preg- nant, the whole of the uterus is about two inches and a half in length, and more than one inch and a half in breadth at the broadest part of the body: it is also near an inch in thickness. It is generally larger than this in women who have lately had children. The uterus is situated in the pelvis between the blad- der and rectum, and is inclosed in a duplicature or fold of the peritoneum, which forms a loose septum that extends from one side of the pelvis to the other, and divides it into an anterior and posterior chamber. The posterior surface of this septum is opposed to the rectum, and the anterior to the bladder. The two portions of this septum, 198 Ligaments of the Uterus. which are between the uterus and the lateral parts of the pelvis, are called the Broad Ligaments. On the posterior surface, the Ovaries are situated on each side of the uterus, being inclosed by a process of the ligament or septum. Above them, in the upper edge of the septum, are the Fallopian Tubes , which are ducts that commence at the upper part of the uterus on each side, and proceed in a lateral direction for some distance, when they form an angle and incline downwards to the ovaries. These ducts are inclosed between the two laminae of the septum for the greater part of their length. The peritoneum, which forms the septum, is reflected from it, posteriorly, to the rectum and the posterior sur- face of the pelvis, and anteriorly, to the bladder. In its progress, in each direction, it forms small plaits or folds; two of which extend from the uterus to the rectum pos- teriorly, and two more to the bladder anteriorly: these are called the Anterior and Posterior Ligaments of the Uterus. The other ligaments, which proceed more immediately from the uterus, are called the Bound Ligaments. These arise from each side of the uterus, at a small distance be- fore and below the origins of the fallopian tubes, and pro- ceed in an oblique course to the abdominal rings. These ligaments are also invested by the peritoneum. They pass through the rings and soon terminate. In the body of the uterus is a cavity which approaches to the triangular form; and from which a canal proceeds through its neck. This cavity is so small that its sides are almost in contact, and the canal is in proportion; so that this organ is very thick in proportion to its bulk. The substance of which the uterus consists is very firm and dense: it is of a whitish colour, with a slight tinge of red. There are many bloodvessels, with nerves and ab- sorbent vessels, in its texture. The nature and structure of this substance has not yet been precisely ascertained. 199 Structure and Cavity of the Uterus. It appears very different indeed from muscle; but the uterus occasionally contracts, with great force, during la- bour. It is not rendered thin by its enlargement during pregnancy, and the bloodvessels in its texture are greatly enlarged at that time. Exteriorly, the uterus is covered by the peritoneum, as has already been mentioned. Internally it is lined with a delicate membrane that has some resemblance to those which secrete mucus, and is generally of a whitish co- lour, abounding with small orifices that can be seen with a magnifying glass. This membrane is so intimately con- nected to the substance of the uterus that some anatomists have supposed it was merely the internal surface of that substance, but this opinion is now generally abandoned. It is supposed that the colour of this membrane is more florid about the period of menstruation. The cavity of the uterus, as has been observed before, is triangular in form. When the organ is in its natural position, the upper side of this triangle is transverse with respect to the body, and the other sides pass downwards and inwards. In each of the upper angles are the orifices of the fallopian tubes, which are of such size as to admit a hog’s bristle. The two lower lines of the triangle are slightly curved outwards at their upper extremities; so that the upper an- gles of the triangle project outwards, and the orifices of the fallopian tubes are nearer to the external surface than they otherwise would be. The lower angle of the cavity of the uterus is occupied by the orifice of the canal, which passes through the neck of the organ; this orifice is from three to four lines in di- ameter. The canal is about an inch in length, and is rather wider in the middle than at either end. On the anterior and posterior portions of its surface are many small ridges which have an arborescent arrangement, one large ridge passing internally from the commencement of the canal, 200 Structure of the Fallopian Tubes. from which a number of other ridges go off in a transverse direction. These ridges extend nearly the whole length of the canal. In the grooves, between the ridges, are the orifices of many mucous ducts. There are also on this surface a number of transparent bodies of a round form, equal in bulk to a middle sized grain of sand; the nature and use of which is unknown. They have been called Ovula JYabothi , after a physiologist, who published some speculations respecting their use, about the commence- ment of the last century. The canal of the neck of the uterus is very different from other ducts, for it seems to be a part of the cavity to which it leads, and when the cavity of the uterus be- comes enlarged in the progress of pregnancy, this canal . is gradually converted into a part of that cavity. The lower extremity of the neck of the uterus is irre- gularly convex and tumid. The orifice of the canal in it is oval, and so situated that it divides the convex surface of the neck into two portions, which are called the Lips. The anterior or upper portion is thicker than the other. This extremity of the uterus protrudes into the vagina, and is commonly called Os Tinea. As the anterior por- tion or lip is larger and more tumid than the posterior,, the vagina extends further beyond the os tincat on the posterior part than on the anterior. The Fallopian Tubes Are two canals, from four to five inches in length, which proceed between the laminae of the broad liga- ments, from the upper angles of the uterus, in a trans- verse direction, to some distance from the uterus, when they form an angle, and take a direction downwards to- wards the ovaries. They are formed, for a considerable part of their extent, by a substance which resembles that of which the uretus 201 Situation of the Ovaries . consists, and are lined by a membrane continued from the internal membrane of the uterus. Their extremities ap- pear to be composed of membrane, which is rendered flo- rid by the bloodvessels in its texture. At the commence- ment their diameters are extremely small; but they en- large in their progress. This enlargement is gradual for the first half, and afterwards sudden; the enlarged part is more membranous than the small part, and has a bright red colour. The large extremity is loose in the cavity of the pelvis, and is not invested by the laminae of the broad ligaments. Near the termination the diameter is often contracted; after which the membrane which forms the tube expands into an open mouth, the margin of which consists of fringed processes: this margin is also oblique, as respects the axis of the tube; and the different fringed processes are not all of the same length; but the longest are in the middle, and the other regularly diminish on each side of them: these processes constitute the Fimbria of the fallopian tubes. The internal surface of the large extremities of these tubes is extremely vascular; and there are some longitu- dinal fibres of a red colour to be seen on it. The Round Ligaments , Which have already been mentioned, are cords of a fibrous structure, with many bloodvessels in them. They arise from the uterus below the origin of the fallopian tubes, and proceed under the anterior lamina of the broad ligament to the abdominal rings, through which they pass; and then the fibres and vessels are expanded upon the contiguous cellular substance. The Ovaries Are two bodies of a flattened oval form; one of which is situated on each side of the uterus on the posterior sur- Vol. II. 2 C 202 Structure of the Ovaries. Corpora Lutea. face of the broad ligament, and invested completely by a process of the posterior lamina, which forms a coat, and also a ligament for it. The size of this organ varies indif- ferent subjects, but in a majority of those who are about the age of maturity it is between ten and twelve lines in length. It is connected to the uterus by a small ligament, or bundle of fibres of the same structure with the round ligaments, which is not more than two lines in diameter, and is included between the laminag of the broad liga- ment. The process of the broad ligament forms an external coat to the ovary; within this is the proper coat of the or- gan, which is a firm membrane. This membrane is so firmly connected to the substance of the ovary which it incloses, that it cannot be easily separated from it. The ovary is of a whitish colour and soft texture, and has many bloodvessels. In virgins of mature age it contains from ten to twenty vesicles, formed of a delicate mem- brane, filled with a transparent coagulable fluid. Some of these vesicles are situated so near to the surface of the ovary that they are prominent on its surface; others are near the center. They are very different in size; the largest being between two and three lines in diameter, and others not more than one third of that size. In women who have had children, or in whom concep- tion has taken place, some of these vesicles are removed; and in their place a cicatrix is found. It has been ascertained, that during the sexual inter- course with males, one of these vesicles, which was pro- tuberant on the surface, is often ruptured, and a cavity is found. A cicatrix is soon formed, where the membrane was ruptured; and in the place occupied by the vesicle there is a yellow substance denominated Corpus Luteum. This corpus luteum generally continues until the middle @f pregnancy: it often remains during that state, and for Arteries of the Uterus. 203 some time after delivery, but it gradually vanishes. The cicatrization continues during life. In many cases these cicatrices correspond with the number of conceptions which have taken place; but they often exceed the number of conceptions, and they have been found in cases where conception has not been known to have taken place. In very old subjects, where conception has never taken place, the vesicles are either entirely removed, or small dense tubercles only remain in their place. The Arteries Of the uterus are derived from two very different sources; viz. from the spermatic and from the hypogas- tric arteries. The spermatic arteries, instead of passing directly down to the abdominal ring, proceed between the laminae of the broad ligament, and send branches to the ovaries, which may sometimes be traced to the vesicles. They also send branches to the fallopian tubes and to the uterus. Those which are on the opposite sides of the uterus anastomose with each other, and also with the branches of the hypo- gastric arteries. There are also branches of these arteries in the round ligaments, which accompany them to their termination outside of the abdominal ring. The principal arteries of the uterus are those derived from the hypogastric, which sends to each side of it a considerable branch, called the Uterine . This vessel leaves the hypogastric very near the origin of the internal pudic, and proceeds to the cervix of the uterus: it passes between the lamina?, of the broad ligaments, and sends branches to the edge of the uterus, which penetrate its texture. The branches which are in the texture of the uterus are very small indeed, in young subjects. In wo- men who have bad children they are considerably larger; 204 Veins of the Uterus. Lymphatics. but during pregnancy they gradually enlarge with the growth of the uterus, and become very considerable. The se arteries observe a serpentine and peculiarly tor- tuous course. Those on the opposite sides anastomose with each other. The Veins Of the uterus, like the arteries, form spermatic and uterine trunks. The Spermatic Vein is much larger than the artery. It ramifies as in males, and forms a very large plexus, which constitutes the corpus pampiniforme. Many of the veins which form this body, originate near the ovary: a considerable number also come from the fal- lopian tubes and the uterus. The spermatic vein and its branches are greatly enlarged indeed during pregnancy; and it is said that they are enlarged the same way during the menstrual discharge. The most important veins of the uterus are the branches of the Uterine V ei ns. They are extremely numerous, and form a plexus on the side of the uterus; from which two or more uterine veins proceed in the course of the artery, and join the hypogastric. These veins also are greatly en- larged during pregnancy. The Lymphatic Vessels Of the uterus, and its appendages, are very numerous. In the unimpn gnated state they are small; but, during pregnancy, they increase greatly. They proceed from the uterus in very different directions. Some that accompany the round ligaments go to the lymphatic glands of the groin. Others which take the course of the uterine blood- vessels pass to glands in the pelvis, and a third set follow the spermatic arteries and veins to the glands on the loins. Bladder and Urethra. 205 The Nerves Of the ovaries are derived from the renal plexus, and those of the uterus and vagina from the hypogastric plexus, or the lower portions of the sympathetic, and the third and fourth sacral nerves. SECTION III. Of the Bladder and Urethra. The situation of the Bladder , as respects the symphy- sis pubis, is nearly alike in both sexes; but that part of it which is immediately behind the insertion of the ure- ters is rather lower in males than in females. The bottom of the bladder rests upon the upper part of the vagina, a thin stratum of cellular substance only intervening: when that viscus is distended it forms a tumor, which com- presses the vagina. The ureters are inserted, and the urethra commences in the same part of the bladder, in both sexes. The length of the Urethra is between one and two inches. When the body is in a direct position, it is nearly horizontal; but it is slightly curved, with its convexity downwards. It is immediately above the vagina, and it passes below the body of the clitoris. The external ori- fice of it is rather more than an inch within the glans or head of the clitoris. This orifice is somewhat prominent in the vagina. In the internal or lining membrane of the urethra there are many orifices of mucous follicles, and also longitudi- nal wrinkles, as in the urethra of males. The diameter of the female urethra and its orifice in the bladder are greater than they are in the male. For this reason it has been 206 Gradual Change in the Gravid Uterus . supposed, that women are less liable to calculus of the bladder than men.* The urethra is intimately connected with the external coat of the vagina, and between them there is a spongy cellular substance which makes the rough surface of the vagina prominent; so that the urethra has been supposed, although erroneously, to be invested with the prostate. It is capable of great artificial dilatation. Of the Changes induced in the Uterus in the progress of Pregnancy. The alteration which takes place in the size of the ute- rus during pregnancy is truly great. About the conclu- sion of that period, instead of the small body above de- scribed, which is almost solid, the uterus forms an im- mense sac, which extends from the termination of the vagina in the pelvis, into the epigastric region; and from one side of the abdomen to the other; preserving, how- ever, an ovoid figure. This change is so gradual at first, that the uterus does not extend beyond the cavity of the pelvis before the third month, although at the end of the seventh month it is very near the epigastric region. For the first six months the body of the uterus appears principally concerned in the enlargement: after this the cervix begins to change, and is gradually altered, so as to compose a portion of the sac, rather of less thickness than the rest of the uterus; the mouth being ultimately an aper- ture in a part which is much thinner than the other por- tions of the organ. _ The change which takes place in the texture of some of the appendages of the uterus is very important. The Broad Ligaments, which seem particularly calcu- lated to favor the extension of the uterus, are necessarily * It has however been asserted that they are also less liable to calculi in the kidneys. General Observations. 207 altered by the change in the size of that organ, but not en- tirely done away. The portion of peritoneum of which they are formed must be very much enlarged with the growth of the uterus, as it continues to cover it. The Round Ligaments are much elongated; and they observe a more straight course to the abdominal ring. The Fallo- pian Tubes are enlarged; and instead of passing off late- rally from the uterus, they now proceed downwards by the side of it. The Ovaries appear rather larger and more spongy: their relative situation is necessarily lower. The change in the Uterus itself is particularly interest- ing. The great increase of its size is not attended with any considerable diminution of thickness in its sub- stance; nor are the arteries much less convoluted than be- fore pregnancy, as might have been expected. They are greatly enlarged in diameter, and the orifices of the exha- lent vessels on the internal surface of the uterus are much more perceptible. The veins are much more enlarged than the arteries., and in some places appear more than half an inch in dia- meter. They are not regularly cylindrical, but rather flat. They anastomose so as to form an irregular net work. The uterus appears much more fibrous and muscular in the gravid than in the unimpregnated state. The con- tractile power of the gravid uterus is not only proved by the expulsion of its contents, but also by very vigorous contractions, which are occasionally observed by accou- cheurs. Although the general effects which result from the par- ticular conditions of the uterus in pregnancy, menstru- ation, &c. evince that the influence of this organ upon the whole system is very great, yet it seems probable that the sexual peculiarities of females are especially dependent upon the ovaria. This sentiment is confirmed by an account of a wo- man in whom the ovaria were deficient, which is pub- 208 Peculiarity of the Female Hottentots. lished in the London Philosophical Transactions for 1805, by Mr. C. Pears. The subject lived to the age of twenty nine years. She ceased to grow after the age of ten years, and therefore was not more than four feet six inches in height: her breadth across the hips was but nine inches, although the breadth of the shoulders was fourteen. Her breasts and nipples never enlarged more than they are in the male subject. There was no hair on the pubes, nor were there any indications of puberty in mind or body. She never menstruated. At the age of twenty-nine she died of a complaint in the breast, attended with convulsions. The uterus and os tincae were found not increased beyond their usual size during infancy. The cavity of the uterus was of the common shape, but its coats were membran us. The Fallopian Tubes were pervious. “ The Ovaria -were so indistinct that they rather showed the rudiments which ought to have formed them , than any part of the natural structured'’ Another case, which confirms the aforesaid sentiment, is related in one of the French periodical publications. It has been long known that a race of savages near the Cape of Good Hope were distinguished from the gene- rality of their species by a peculiarity about the puden- dum. An account of this structure has been given with some precision by Messrs. Peron and Lesueur, in a paper which was read to the National Institute of France. It is a flap or apron, four inches in length, which is united to the external labia near their upper angle, and hangs down before the clitoris and the external orifice of the parts of generation. It is divided below into two lobes, which cover the orifice. It is formed by a soft distensible skin, free from hair, which is occasionally corrugated like the scrotum, and is rather more florid than the ordinary cutis.* * This paper has not yet been published by the Institute, but it is referred to by M. Cuvier in his Le$ons d’Anatomie Comparee, vol. v. page 1 24. — Messrs. Peron and Lesueur were naturalists who accompanied captain Baudin in his voyage of discovery. Peculiarities in the Abdomen of the Foetus. 209 The Abdomen of the Foetus. The difference between the fetus and the adult, in the cavity of the abdomen, is very conspicuous at the first view. The Liver in the fetus is so large that it occupies a very considerable part of the abdomen. Its left lobe, which is larger in proportion than the right, extends far into the left hypochondriac region. The Bladder of urine, when filled, extends from tile cavity of the pelvis a considerable distance towards the umbilicus; so that the greatest part of it is in the cavity of the abdomen. A ligament of a conical figure extends from the center of the upper part of the bladder to the umbilicus; with an artery on each side of it, which is soon to be described. This ligament, which is in the situation of the urachus of the fetus of quadrupeds, is hollow, and thus frequently forms a canal, which has a very small diameter, that communicates with the bladder by an aper- ture still smaller, and continues a short distance from the bladder towards the umbilicus. In a few' rare instances this canal has extended to the umbilicus, so that urine has been discharged through it, but the ligament is commonly solid there. The Stomach appears to be more curved in the fetus than in the adult. The Great Intestine does not extend sufficiently far, be- yond the insertion of the ileon, to form the caecum com- pletely. The Glandules Renales are much larger in proportion in the foetus than in the adult. The colour of the fluid they contain is more florid. The Kidneys are lobulated. The Testicles in the fetus are found above the pelvis, in the lumbar region, behind the peritoneum, until two Voi. II. 2 D 210 Descent of the Testicle in the Foetus. months before birth. Thus situated, their bloodvessels and nerves proceed from sources which are near them; but the vas deferens, being connected to the vesiculae seminales by one extremity, is necessarily in a very different situa- tion from what it is in the adult: it proceeds from the tes- ticle downwards to the neck of the bladder. — While each testicle is in this situation, it is connected with a sub- stance or ligament, called Gubernaculum, of a conical or pyramidical form, attached to its lower end, and extends from it to the abdominal ring. This substance is vas- cular, and of a fibrous texture: its large extremity ad- heres to the testicle, its lower and small extremity- passes through the abdominal ring, and appears to ter- minate in the cellular substance exterior to that open- ing, like the round ligament in females. The Guber- naculum , as well as the testicle, is behind the peritoneum; and the peritoneum adheres to each of them more firmly than it does to any of the surrounding parts. It seems that, by the contraction of the Gubernaculum , the testicle is moved down from its original situation to the abdo- minal ring, and through the abdomipal ring into the scrotum. The peritoneum, which adheres firmly to the gubernaculum and testicle, and is loosely connected to the other parts, yields to this operation; and when the tes- ticle has arrived near the abdominal ring, a portion of the peritoneum is protruded a little way before it into the scrotum; forming a cavity like the finger of a glove. The testicle passes down behind this process of the peritoneum, and is covered by it as it was in the abdomen. Although it appears protruded into the cavity, it is exterior to it, and behind it; and the vessels, See. which belong to the testicle are also exterior to it. The cavity formed in the scrotum, by this process of the peritoneum, necessarily communicates with the cavity of the abdomen at its formation; but very soon after the testicle has descended into the scrotum, the upper part of Umbilical Vessels. 211 this cavity is closed up, while the lower part of the pro- cess continues unchanged, and constitutes the Tunica Vaginalis Testis. In some instances the upper part of this process does not close up, and the communication with the cavity of the abdomen continues. The descent of the intestine into the cavity thus circumstanced, constitutes that species of hernia which is denominated Congenital .* The most important peculiarities in the abdomen of the foetus are those connected with the circulation of the blood. The internal iliac or hypogastric arteries are larger than the external iliacs. Their main trunks are continued on each side of the bladder to its fundus; and proceed from it, with the ligament, to the umbilicus; when they pass out of the abdomen to go along the umbilical cord to the placenta. These arteries are now denominated the Umbili- cal , and are very considerable in size. After birth, as there is no circulation in them, they soon begin to change: the cavity of them is gradually obliterated, and they are converted into ligaments. They are exterior to the peri- toneum, and contained in a duplicature of it. A vein also called the Umbilical , which is much larger * These interesting circumstances respecting the original situa- tion of the testicle, and its descent into the scrotum, were disco- vered and elucidated by Haller, Hunter, Pott, Camper, and several other very respectable anatomists and surgeons. There is however a difference of opinion, between some of them, as to the time when the testicle leaves the abdomen. Haller thought the testicles were seldom in the scrotum at birth. Hunter and Camper found them so generally. It has been suggested that there are some national peculiarities in this respect; that amongst the Hungarians, for example, the testi- cles often remain above the abdominal ring until near the age of puberty. The student will find an interesting description of the situation of the testis, and its descent, in the foetus, in the lC Observations on certain parts of the Animal Economy,” by John Hunter. £12 Ductus Venosus . in diameter than both of the arteries, returns from the placenta along the cord, and enters the cavity of the ab* domen at the umbilicus. It proceeds thence, exterior to the peritoneum, but in a duplicature of it called the Fal- ciform Ligament , to the liver, and enters that viscus at the great fissure; along which it passes to the left branch of the sinus of the vena portarum, into which it opens and discharges the blood which flow's through it from the placenta. It opens oh the anterior side of the branch of the vena portarum, and from the posterior side of the branch, opposite to this opening, proceeds a duct or canal, which opens into the left hepatic vein near its junction with the vena cava. This communicating vessel is called the Duc- tus , or Canalis Venosus; to distinguish it from the duct which passes from the pulmonary artery to the aorta, and is calltd Ductus , or Canalis Arteriosus. This venous duct carries some of the blood of the umbilical vein directly to the vena cava; but it is much smaller than the umbilical vein, and of course a considerable quantity of the blood which passes through the umbilical vein must pass through the liver, by the vena portarum, before it can enter the Cava. In some foetal subjects, if a probe of sufficient length be introduced within the umbilical vein and pushed forwards, it will pass to the heart without much difficulty or oppo- sition, as if it proceeded along one continued tube, al- though it really passes from the umbilical vein across the branch of the vena portarum, and then through the ductus venosus, and through a portion of the left hepatic vein, into the inferior vena cava. If the umbilical vein be injected w'ith a composition, which will be firm when cool, it appears to terminate in a rounded end, which is situated in the transverse fissure of the liver: the sinus of the vena portarum, into which this vein enters, appears like two branches going off, one from each side of it, and the ductus venosus like Object of the Circulation in the Placenta. 21$ a branch continuing in the direction of the main trunk of the umbilical vein. The umbilical vein, in its progress through the fissure «of the liver, before it arrives at the sinus of the vena por- tarum, sends off a considerable number of branches to each of the lobes of that organ, but more to the left than to the right lobe. After birth, when blood ceases to flow through the um- bilical vein, it is gradually converted into a ligament; and the venous duct is also converted into a ligament in the same manner. The vena portarum, which before appeared very small, when compared with the umbilical vein, now brings all the blood which fills its great sinus, and increases considerably in size. It has been ascertained by anatomical investigation, that the umbilical arteries above mentioned, after ramify- ing minutely in the placenta, communicate with the mi- nute branches of the umbilical vein; and it is probable that the whole blood carried to the placenta by these arteries, returns by the umbilical vein to the foetus. It is clearly proved by the effects of pressure on the umbilical cord, in cases of delivery by the feet, as well as by other similar circumstances, that this circulation ctvi- not be suspended for any length of time without destroy- ing the life of the foetus. From these circumstances, and from the florid colour which the blood acquires by circu- lating in the placenta, it seems probable that the object of the circulation through that organ is somewhat analogous to the object of the pulmonary circulation through the lungs of adults. * * During the first four months of pregnancy a very small vesicle, which does not exceed the size of a pea, is found between the chorion and the amnios, near the insertion of the umbilical cord into the pla- centa. It is connected to the foetus by an artery and a vein, which pass from the abdomen through the umbilicus, and proceeding along the cord to the placenta, continue from it to the vesicle. The 214 Object of the Circulation in the Placenta. artery arises from the mesenteric, and the vein is united to the me- senteric branch of the vena portarum. It is probable that these ves- sels commonly exist no longer than the vesicle, viz. about four months; but they have been seen by Haller and Chaussier at the termination of pregnancy. They are called Omfihalo Mesenteric vessels. The vesicle is denominated the Umbilical Vesicle. This inexplicable structure is delineated in Hunter’s Anatomy of the Gravid Uterus, plate xxxiii. figures v. and vi.; in the Aca- demical Annotations of Albinus, first book, plate i. figure xii.j and also in the leones Embryonum Humanorum of Soemmering, figure ii. SYSTEM OF ANATOMY. PART IX. OP THE BLOODVESSELS. The Bloodvessels are flexible tubes, of a peculiar texture, through which blood passes from the heart to the different parts of the body, and returns again from these parts to the heart. They are to be found, in varying proportions, in almost every part of the body, and seem to enter into its texture. The tubes, which carry blood from the heart, are more substantial and more elastic than those through which it returns to the heart. They are generally found empty after death; and, therefore, were called Arteries by the ancient anatomists, who supposed that they carried air, and not blood. The tubes which return the blood to the heart are denominated Veins. They are less substantial and less elastic than arteries, and are generally full of blood in the dead subject. There are two great arteries, from which all the other arterial vessels of the body are derived. They are very justly compared to the trunks of trees, and the smaller vessels to their branches. One c r these great arteries, 216 The Bloodvessels in general. called the Aorta , carries blood to every part of the body. The other great vessel, called the Pulmonary Artery, carries blood exclusively to the lungs. The veins which correspond to the branches of the Aorta , unite to each other, so as to form two great trunks that proceed to the heart. One of these trunks, coming from the superior parts of the body, is called the Superior , or Descending Vena Cava. The other, which comes from the lower parts of the body, is called the Inferior, or Ascending Vena Cava. The veins which correspond with the branches of the Pulmonary Artery , and return to the heart the blood of the lungs, are four in number: two of them proceeding from each lung. They are called Pulmonary Veins. In many of the veins there are valves, which prevent the blood they contain from moving towards the surface and extremities of the body, but allow it to pass towards the heart without impediment. From the construction of the cavities of the heart, and the position of the valves which are in them; as well as the situation of the valves at the commencement of the great arteries , and the above mentioned valves of the veins, it is evident, that when the blood circulates, it must move from the heart, through the aorta and its branches, to the differ- ent parts of the body, and return from these parts through the venae cavas to the heart; that, when deposited in the heart by the venae cavae, it must proceed through the pul- monary artery to the lungs, and return from the lungs through the pulmonary veins to the heart, in order to pass again from that organ into the aorta. It is also certain, that the blood is forced from the heart into the arteries, by the contraction of the muscular fibres of which the heart is composed; and that the blood- vessels likewise perform a part in the circulation, they propelling the blood which is thus thrown into them: but their action appears to depend upon causes of a complex nature. CHAPTER I. OF THE GENERAL STRUCTURE AND ARRANGEMENT OF THE BLOODVESSELS. SECTION I. Of the Arteries. XHE arteries are so much concerned in the important function of the circulation of the blood, that every cir- cumstance connected with them is very interesting. They are composed of coats or tunics, which are very elastic and strong, and which arc also very thick. In con- sequence of the firmness of their coats, they continue open, after their contents are discharged, like hard tubes. They submit to great dilatation, and elongation, when fluids are forced into them, and return to their former dimensions when the distending cause is withdrawn. This elasticity is particularly subservient to the circulation of the blood. It admits the artery to distend readily, and receive the blood which is thrown into it by the contrac- tion of the heart. It also produces the contraction of the artery; which takes place as soon as the action of the heart ceases; and this contraction of the artery necessarily forces the blood forward, as the valves at its orifice pre- vent it from returning to the heart. The motion of the artery, which is so easily perceived by the touch, and in many instances also by the eye, is completely explained by the discharge of blood into the artery from the heart, and by the elasticity of the vessel, by which it reacts upon the blood. In some cases it is not Vol, II. 2 E 218 Structure of the Arteries. simply the diameter of the artery which is enlarged, but a portion of the vessel is elongated; and this elongation, by producing a curvature of it, renders its motion more visible. In the aorta, and probably in its large branches, Elasti- city seems to be the principal cause of the continuance of the motion which is originally given to the blood by the heart. But there are many circumstances connected with the smaller vessels, which evince that they exert a power which is very different indeed from elasticity. Thus the application of local stimulants or rubefacients, and of heat, is followed by an increase of motion in the arteries of the parts to which they are applied. Neither of these causes could produce their effect by the influence of elasticity: but the effect of these and other similar causes is uniformly produced; and a power of inde- pendent motion, or Irritability , is thus proved to exist in these vessels, and seems essentially necessary to the circulation of the blood. The Structure of the Arteries Is, therefore, a subject of importance, and has reeeived a considerable degree of attention from anatomists. They are composed of a dense elastic substance, of a whitish colour. Their external surface is rough, and intimately connected with the cellular membrane, which every where surrounds it in varying quantities. Inter- nally, they are lined with a thin membrane, which is very smooth and flexible, and is also very elastic. The sub- stance which composes the artery, and is situated between the cel 1 ar investment and the internal membrane, con- sists of fibres, which are nearly, though not completely, circular, but so arranged as to constitute a cylinder. These fibres may be separated from each other so as to form laminze, which have been considered as different coats of 219 Structure of the Arteries. the arteries; but there is no arrangement of them which composes regular distinct strata. The coats of arteries may, therefore, be separated into a greater or smaller number of laminae, according to the thickness of these lamina;. The fibres which compose these laminae appear to be united to each other in a way which readily allows of their separation, at the same time that they form a firm texture. Although arteries thus appear essentially different from muscles in their hardness and their elasticity, as well as in their general texture, they are considered, by a great majority of anatomists, as partaking more or less of a muscular structure. In the human subject their structure is very difficult of demonstration, and great differences exist in the accounts which are given of it, even by anatomists, who agree in the general sentiment that the arteries are muscular. Thus Haller believed that muscular fibres were most abundant in the large arteries, while J. Hunter thought the reverse. Hunter appears to have investigated this subject with great attention, and supposed the muscular substance, in the composition of arteries, to be interior, and the elastic matter exterior; that in large arteries this muscular sub- stance is very small in quantity, and gradually increases in proportion as the artery diminishes in size. He however observes, that he never could discover the direction of the muscular fibres .* When the great talents of Mr. Hunter, as an anatomist, are considered, this circumstance cannot fail to excite a belief that the existence of these fibres is not certain: and if to this be added the fact, that even the red coloured substance of the arteries is elastic, and in that respect dif- ferent from muscular substance, the reasons for doubt- ing must be increased. * Treatise on the Blood, &c. Vol. I. p. 1 1 J. Bradford’s edition. 220 Question respecting the muscularity of Arteries. Bichat appears to have entertained very strong doubts on the subject; but he stands almost alone; for a large number both of the preceding and cotemporary anato- mists, seem to have adopted the sentiment, that the arte- ries have a muscular structure. The student of anatomy can very easily examine this subject himself, by separating the coats of arteries into dif- ferent lamina; and by viewing the edges of the transverse and longitudinal sections of those vessels. While thus engaged with this question, he will read with great advan- tage what has been written upon it by Mr. Hunter, in his Treatise on the Blood, See. See chapter second, section 3. Bichat ought also to be read upon this subject, which he has discussed in his Anatomie Generale — System Vascu- laire a Sang Rouge , article Troisieme, See. and also in his Traite des Membranes , article Sixieme. The belief of the irritability of arteries does not, how- ever, rest upon the appearance of theii hbres. 1. It is asserted by very respectable authors,* that they have been made to contract by the application of mecha- nical and of chemical irritation, and also of the electric and galvanic power. 2. A partial or local action of arteries is often pro- duced by the local application of heat and rubefacients, as has been already observed. 3. Arterial action is often suspended in a particular part by the application of cold. It has also been observed that the arteries have for a short time ceased to pulsate in cases of extreme contusion and laceration of the limbs. t * See Soemmering on the structure of the Human Body, Vol. IV”. German edition. Dr. Jones on the Process employed by nature for suppressing Haemorrhage, &c. t This local suspension of arterial motion by cold, kc., applied locally, is very difficult to explain; as the action of the heart and the elasticity of the arteries appear sufficient to account for the pulsation of the large arteries. Proofs of the Irritability of the Arteries. 221 4. When arteries are divided transversely in living animals, they often contract so as to close completely the orifice made by the division. 5. In a horse bled to death, it was ascertained by Mr. Hunter, that the transverse diameter of the arteries was diminished to a degree that could not be explained by their elasticity. He also found that, after death, the arteries, especially those of the smaller size, are generally in a state of contraction, which is greater than can be explained by their elasticity: for if they are distended mechanically, they do not contract again to their former size, but continue of a larger diameter than they were before the distention; although their elasticity may act so as to restore a very considerable degree of the contraction observed at death. The contraction, which is thus done away by disten- tion, Mr. Hunter supposed to have been produced by muscular fibres: for, if it had been dependent on elastici- ty, it must have reappeared when the distending power was withdrawn. It therefore seems certain, that the arteries have a power of contraction different from that which depends upon elasticity: but whether this depends upon muscular fibres superadded to them, or upon an irritable quality in the ordinary elastic fibres of bloodvessels, is a question which is not perhaps completely decided. The motion of the blood in the arteries appears to depend, 1st, Upon the impulse given to it by the action of the heart. 2dly, Upon the elasticity of the arteries, in consequence of which they first give way to the blood impelled into them, and then react upon it; and 3dly, Upon the power of contraction in the arteries, or their irritability. In the larger arteries the blood seems to move as it 222 General Observations on the Arteries * Would through an inanimate elastic tube, in consequence of the impulse given by the heart, and kept up by the arteries themselves. In the smaller vessels it seems pro- bable that the motion of the blood depends in a consi- derable degree upon the contraction Which arises from their irritability. The obvious effect of the elasticity of the arteries is to resist distention and elongation, and to contract the artery to its natural state, when the distending or elongating cause ceases to act. But it must also resist the contraction induced by the muscular fibres, and restore the artery to its natural size when the muscular fibres cease to act after contracting it, as has been observed by Mr. Hunter. It seems probable that all the fibres of which the artery consists are nearly but not completely circular; for it is not certain that there are any longitudinal fibres in the structure of an artery. The internal coat of these vessels is very smooth, but extremely dense and firm; and seems to be rendered moist and flexible by an exudation on its surface. It adheres very closely to the contiguous fibres of the coat exterior to it, but may be very readily peeled off from them. It is of a whitish colour, and, like the fibrous structure of the artery, is very elastic. Like that sub- stance also it is easily torn or broken, and, when ligatures have been applied to arteries, it has been often observed that the fibrous structure and the internal coat have been separated, while this external cellular coat has remained entire. The arteries are supplied with their proper blood- vessels and lymphatics. It is to be observed, that the bloodvessels are not derived from the artery on which they run, but from the contiguous vessels. These vessels have nerves also, which are rather small in size, when compared with those which go to other parts. General Observations on the Arteries. 223 Arteries appear to have a cylindrical form, for no di- minution of diameter is observable in those portions of them which send off no ramifications. When an artery ramifies, the area of the different branches exceeds considerably that of the main trunk. Upon this principle the aorta and its branches have been compared to a cone, the basis of which is formed by the branches, and the apex of the trunk. The transverse section of an artery is circular. There are no valves in the arteries, except those of the orifices of the aorta and the pulmonary artery, at the heart. The valves of the pulmonary artery have been described in the 53d page of this volume, and those of the aorta have an exact resemblance to them, but are rather larger. The course of the arteries throughout the body is ob- viously calculated to prevent their exposure to pressure, or to great extension from the flexure of the articulations by which they pass. With this view they sometimes pro- ceed in a winding direction; and when they pass over parts which are subject to great distention or enlarge- ment, as the cheeks, they often meander; and, therefore, their length may be increased by straightening, without stretching them. Their course appears sometimes to have been calcula- ted to lessen the force of the blood, as is the case with the Internal Carotid and the Vertebral arteries. In the trunk of the body the branches of arteries gen- erally form obtuse angles with the trunks from which they proceed. In the limbs these angles are acute. The communication of arteries with each other is termed Anastomosis. In some instances, two branches which proceed in a course nearly similar, unite with an acute angle, and form one common trunk. Some- times, a transverse branch runs from one to the other, so as to form a right angle with each. In other cases, 224 General Observations on the Veins. the two anastamosing branches form an arch, or portion of a circle, from which many branches go off. By successive ramifications, arteries gradually dimi- nish in size, until they are finally extremely small. The smallest arteries do not carry red blood, their diameters being smaller than those of the red particles of that fluid: the serous or aqueous part of the blood can, therefore, only pass through them. Many of the arteries which carry red blood, and of the last mentioned serous arteries terminate in veins, which are, in some respects, a continuation of the tube reflected backwards. They likewise terminate in exhalent vessels, which open upon the external surface, and upon the various internal surfaces of the body. The secretory vessels of glands are likewise the termination of many atteries. SECTION II. Of the Veins. THESE tubes, which return to the heart the blood carried from it by the arteries, are more numerous than the arteries, and often are larger in diameter. They generally accompany the arteries, and very often two veins are found with one artery. In addition to these last mentioned veins, which may be called deep-seated , there are many subcutaneous veins which appear on almost every part of the surface of the body. The capacity of all the veins is therefore much greater than that of all the arteries. Those subcutaneous veins, which are of considerable 225 Coats of V eins. size, communicate very freely with each other, and also with the deep-seated veins. The trunks of the veins, in those places where no branches go off, are generally cylindrical. There are however some exceptions, in which these vessels are irre- gularly dilated, as sometimes happens in the case of the internal jugular vein. It is, however, not easy to determine from the appearance of veins injected after death, respect- ing their situation during life, as their coats are very yielding; and it is very probable that they are, therefore, preternaturally dilated by the injection. Veins , directly or indirectly, originate from the termi- nation of arteries: but they do not pulsate as the arteries do, because the impulse given to the blood by the heart is very much diminished in consequence of the great diminution of the size of the vessels through which the blood has passed. In some cases, however, when blood flows from an opened vein; the extent of its projection is alternately increased and diminished, in quick succession, as if it were influenced by the pulsation of the heart. The Coats of Veins differ considerably from those of Arteries , — for they are thinner, and so much less firm , that veins, unlike arteries, collapse when they are empty. They consist of a dense elastic substance, the fibres of which are much less distinct than those of arteries, but some of them are to be seen in a longitudinal direction. These fibres can be made to contract by loc\J irritation ; for if a vein be laid bare in a living animal, and then punctured, it will often contract so as to diminish its diameter very considerably, although no blood shall have escaped from the punctures. Nextto the elastic substance is the internal coat, which is smooth and polished. It is separated from the substance exterior to it with difficulty, although it may be taken from it very easily in the vena cava. Vol. II. 2 F 226 Colour of the Blood in the Veins. This internal coat is more distendible than the internal coat of arteries, and is not, like the latter, disposed to os- sification. It is frequently so arranged as to form valves, which are plaits or folds, of a semilunar form, that project from the surfaces into the cavities of these vessels. Two of these valves are generally placed opposite to each other; and, when raised up, they form a septum in the cylindrical cavity of the vessel. The septum, thus composed, is concave towards the heart. The valves have a great effect in preventing the contents of the veins from moving in a retrograde course: they, therefore, necessarily modify the effects of lateral pressure, in such a manner, that it propels the blood forward, or to the heart. These valves are generally found in the veins of the muscular parts of the body, especially in those of the extremities. They are not found in those veins which are in the cavities of the body, nor in the internal jugulars. — They are placed at unequal distances from each other. The coats of the veins are somewhat transparent; and, therefore, those veins which are subcutaneous have a bluish aspect, which is derived from the colour of the blood they contain. The colour of the blood in the Veins is different from that in the arteries, being of a darker red. The situation and arrangement of the large trunks of veins is much alike in different subjects; but the branches, especially those which are subcutaneous, are very variable in their situations. 227 CHAPTER II. A PARTICULAR ACCOUNT OF THE DISTRIBUTION OF THE ARTERIES. SECTION I. Of the AORTA, Or the Great Trunk of the Arterial System. When the heart is in its natural position, the right ventricle is nearly anterior to the left; and, therefore, the AORTA, where it originates from the left ventricle, is behind the pulmonary artery, and covered by it. Its first direction is so oblique towards the right side of the body, that it crosses the pulmonary artery behind, and appears on the right side of it. It has scarcely assumed this posi- tion before its course alters, for it then proceeds obliquely backwards, and to the left; so as to form a large curve or arch, which extends to the left of the spine. The position of this curve or arch is so oblique, with respect to the body, that the cord or diameter of it, if it were extended anteriorly and posteriorly, would strike the cartilage of the second or third right rib about the mid- dle of its length, and the lejt rib near the head. In conse- quence of this position of the curve, the AORTA crosses over the right branch of the pulmonary artery, and the left branch of the windpipe: and assumes a situation, in front, and to the left of the third dorsal vertebra: from this situation it proceeds downwards; in front, but rather on the left side of the spine, and in contact with that co- lumn. 228 Situation of the Aorta in the Thorax and Abdomen. The AORTA, as well as the Pulmonary Artery , for a small distance from the heart, is invested by the peri- cardium; and, when that sac is opened, appears to be contained in it. After crossing the right branch of the Pulmonary Artery , a ligament is inserted into it, which proceeds from the main trunk of the pulmonary artery at its divi- sion: this ligament was the Canalis Arteriosus in the foetus. As the AORTA proceeds down the spine, it is situa- ted between the two laminae of the mediastinum, and in contact with the left lamina, through which it may be seen. It descends between the crura of the diaphragm, in a vacuity which is sufficiently large to admit of its pas- sage without pressure from the surrounding parts, and is still in contact with the anterior surface of the spine, but rather to the left of the middle of it. It continues this course along the spine until it arrives at the cartilaginous substance between the fourth and fifth lumbar vertebrae, when it divides into two great branches of equal size, which form an acute angle with each other. These are de- nominated the COMMON, or PRIMITIVE ILIAC Arteries. From the AORTA in this course are sent off the ar- teries which are distributed to all the parts of the body for their nourishment and animation, From the curve proceed the great branches which sup- ply the heart, the head, the upper extremities, and part of the thorax. Between the curve and the great primitive iliac arteries, the AORTA sends off those branches which supply the viscera contained in the cavities of the thorax and abdomen,* and part of the trunk of the body. The great ILIAC branches of the AORTA are divided into * It ought to be observed here, that the viscera in the lower part of the pelvis receive some branches from the internal iliac arteries. Origin of the Subclavian and Carotid Arteries [. 229 smaller arteries, which supply the whole of the lower extremities and some of the viscera of the pelvis. SECTION II. Of the Branches which go off from the arch of the AORTA. THE proper arteries of the heart, denominated coro- nary arteries, proceed from the AORTA so near to the heart that their orifices are covered by the semilunar valves, when those valves are pressed against the sides of the artery. These arteries have been described in the account of the heart. — See p. 57. The arteries of the head and of the upper extremities proceed from the upper part of the curve in the following manner. A large trunk, called ARTERIA INNOMINATA, goes off first. This is more than sixteen lines in length, tvhen it divides into two branches: one of which supplies the right side of the head, and is denominated the RIGHT CAROTID: the other proceeds to the right arm, and from its course under the clavicle, is called, at first, the RIGHT SUBCLAVIAN. Almost in contact with the first trunk, another artery goes off, which proceeds to the left side of the head, and is called the LEFT CARO FID. Very near to this, arises the third artery, which proceeds to the left arm, and is denominated the LEFT SUBCLA- VIAN. From these great branches originate the blood- vessels, which are spent upon the head and neck and the upper extremities. As these arteries arise from the curve of the AORTA, they are situated obliquely with respect to each other. 230 Situation of the Common Carotid Arteries. *1 he ARTERIA INNOMINATA is not only to the right, but it is also anterior to the two others: and the LEF I’ SUBCLAVIAN is posterior, as well as to the left of the LEFT CAROTID and the ARTERIA IN- NOMINATA. THE CAROTID ARTERIES. The two carotid arteries above mentioned have been denominated COMMON CAROTIDS, to distinguish them from their first ramifications, which are called IN- TERNAL and EXTERNAL CAROTIDS. THE COMMON CAROTIDS Proceed towards the head on each side of the trachea: at first they diverge, but they soon become nearly parallel to each other, and continue so until they have ascended as high as the upper edge of the thyroid cartilage, when they divide into the INTERNAL and EXTERNAL CAROTIDS. These arteries are at first very near each other, and rather in front of the trachea; they gradually diverge and pass backwards and outwards on the sides of it, and of the oesophagus, until they have arrived at the larynx. In the lower part of the neck they are covered by the sterno mastoidei, the sterno hyoidei, and thyroidei, as well as by the platysma myoidei muscles. Above, their situation is more superficial; and they are immediately under the platysma myoides. On the inside, they are very near the trachea and la- rynx, and the oesophagus; on the outside, and rather ante- rior to them, are the internal jugular veins; and behind, on each side, are two important nerves called the inter- costal and the parvagum. These bloodvessels and nerves are surrounded by absorbent vessels. External Carotid Artery. 231 The COMMON CAROTID ARTERIES send off no branches from their origin to their bifurcation; and they appear to preserve the same diameter throughout their whole extent. In some few instances the right caro- tid has been found larger than the left. The external and internal branches into which they divide, are nearly equal in the adult; but it is supposed that the internal is the largest during infancy. The relative position of these branches is also different at the commencement from what it is afterwards. The INTERNAL CAROTID forms a curve which projects outwardly, so as to be exterior to the EXTERNAL CAROTID, while this last proceeds up- wards, and rather backwards. THE EXTERNAL CAROTID ARTERY May be considered as extending from its commence- ment, which is on a line with the superior margin of the thyroid cartilage, to the neck of the condyle of the lower jaw, or near it. At first it is superficial; but as it proceeds upwards it becomes deep-seated; and passing under the digastric and stylo hyoidei muscles, and the ninth pair of nerves, is co- vered by the Parotid Gland. After this, it again becomes superficial; for the temporal artery, which may be regard- ed as the continuation of the external carotid, passes over the zygomatic process of the temporal bone. As the external carotid supplies with blood the upper part of the neck and throat, the exterior of the head and face, and the inside of the mouth and nose; its branches must necessarily be numerous, and must pass in very va- rious directions. Thus, soon after its commencement, it sends off, in an anterior direction, three large branches; viz. to the upper part of the neck, to the parts within the lower jaw, and to the cheeks and lips. These are denominated, the stjpe- 232 External Carotid and its Branches. rior thyroid, the sublingual, and the facial. It then sends off to the back of the head one which is called the occipital; and, as it proceeds upwards near the con- dyle of the lower jaw, another which passes internally, be- hind the jaw, to the deep-seated parts in that direction. After this, it forms the temporal artery, which supplies the forehead and central parts of the cranium. Besides these larger branches, the external carotid sends off two which are smaller; one from near the origin of the sublin- gual artery, which is spent principally upon the pharynx and fauces, and is called the inferior pharyngeal: and another, while it is involved with the parotid gland, which goes to the ear; and is therefore called posterior auris. These arteries are distributed in the following manner. 1. The Superior thyroid branch Comes off very near the root of the external carotid, and sometimes from the common trunk; it runs obliquely downwards and forwards, in a meandering course, to the thyroid gland, where it is spent. During this course it sends off one branch to the parts contiguous to the os hyoides; another to the neighbourhood of the larynx: and a third branch, which may be termed Laryngeal , that passes with a small nerve derived from the laryngeal branch of the par vagum, either between the os hyoides and thyroid cartilage, or the thyroid and cricoid carti- lages, to the interior muscles of the larynx; and finally returns again to terminate externally. While in the thyroid gland this artery anastomoses with the inferior thyroid, and also with its fellow on the opposite side. Branches of the External Carotid. 233 2. The lingual, or sublingual branch, Goes off above the last mentioned arter}', and very near it; but in a very different direction, for it runs upwards and forwards, to the tongue. In this course it crosses obliquely the os hyoides, and is commonly within the hyoglossus muscle. It gives off branches to the middle constrictors of the pharynx, and to the muscles contigu- ous to the tongue. It also sends off a branch which pene- trates to the back of the tongue, which is called, from its situation, Dorsalis Lingiue. At the anterior margin of the hyoglossus muscle it divides into two branches, one of which passes to the sublingual gland and the adjacent parts, and is thence called Sublingual ; while the other branch, the Banina, passes by the side of the genio glos- sus muscle to the apex of the tongue. 3. The facial or external maxillary, Runs obliquely upwards and forwards under the ninth pair of nerves, the stylo hyoideus muscle and the tendon of the digastric, across the lower jaw and cheek, towards the inner corner of the eye, in a serpentine course. Be- fore it crosses the jaw it sends off several branches, viz: to the pharynx, the tonsils, the inferior maxillary gland and the parts contiguous to it. It also sends a branch towards the chin, which passes between the mylo-hyoi- deus, the anterior belly of the digastric, and the margin of the lower jaw: and some of its branches continue to the muscles of the under lip. This branch is called the Submental. This artery then passes round the basis or inferior edge of the lower jaw, very near the anterior margin of the masseter muscle, and is sp superficial that its pulsa- tions can be readily perceived. After this turn, its course VoL. II. 2 G "34 Branches of the External Carotid. is obliquely upwards, and forwards. Near the basis of the jaw it sends off a branch to the masseter, which anastomoses with small branches from the temporal; and another which passes superficially to the under lip and contiguous parts of the cheeks. This last is called the Inferior Labial. After the artery has passed as high as the teeth in the lower jaw, it divides into two branches; which go, one to the under, and the other to the upper lip: that to the upper lip is largest. These branches are called Coronary. The Coronary Artery of the lower lip passes under the muscles called Depressor Anguli Oris , and Orbicularis Oris , into the substance of the lip, and anastomoses with its fellow of the opposite side. The Coronary Artery of the upper lip passes under the zygcmaticus major and the orbicularis, and very near the margin of the upper lip internally. It also anasto- moses freely with its fellow on the opposite side. These anastomoses are frequently so considerable that the ar- teries on one side can be well filled by injecting those of the other. The coronary branches, as well as the main trunk of the facial artery, observe a serpentine or tor- tuous course; in consequence of which they admit of the motions of the cheeks and lips, which they would greatly impede if they w r ere straight. From the upper coronary artery a branch continues in the direction of the main trunk of the facial artery, by the side of the nose, which extends upwards, sending off small branches in its course, and finally terminates about the internal angle of the eye and the forehead. 4. The INFERIOR PHARYNGEAL Is a very small artery; it arises posteriorly from the ex- ternal carotid, opposite to the origin of the sublingual, and passes upwards to the basis of the cranium. In this Branches of the External Carotid. 235 course it sends several branches to the pharynx, and to the deep seated parts immediately contiguous. It also sends branches to the first ganglion of the inter- costal nerve, to the par vagum, and to the lymphatic glands of the neck; and finally it enters the cavity of the cranium by the posterior foramen lacerum. In some cases it also sends a small branch through the anterior foramen lacerum. 5. The occipital artery Arises from the posterior side of the external carotid, nearly opposite to the facial, but sometimes higher up; it ascends obliquely, and passes to the back part of the cranium, between the transverse process of the atlas and the mastoid process of the temporal bone. In this course it passes over the internal jugular vein and the eighth pair of nerves, and under the posterior part of the digastric muscle; it lies very near to the base of the mastoid process, and under the muscles -which are inserted into it. After emerging from these muscles, it runs superficially upon the occiput, dividing into branches which extend to those of the temporal artery. The occipital artery sends off branches to the muscles which are contiguous to it, and to the glands of the neck. It also gives off the following branches: One called the Meningeal , which passes through the posterior fora- men lacerum to the under and back part of the dura mater: one to the exterior parts of the ear: another tvhich passes downwards, and is spent upon the complexus, trachelo mastoideus, and other muscles of the neck: and several smaller arteries. The artery next to be described, is sometimes sent off by the occipital artery. 236 Branches of the External Carotid. 6. The POSTERIOR AURICULAR, Or STYLO MASTOID ARTERY, When it arises from the external carotid, comes off pos- teriorly from the artery, where it is involved with the parotid gland, and passes backwards between the meatus auditorius externus and the mastoid process. It then as- cends, in a curved direction, and terminates behind the ear. In this course it sends off small branches to the paro- tid gland, and to the digastric and sterno mastoid muscles. Sometimes a distinct branch, which is particularly visi- ble in children, passes through an aperture in the meatus auditorius externus, and is spent on its internal surface. It also sends off a branch which enters into the Stylo Mastoid Foramen , and supplies small vessels to the mem- brana tympani and the lining membrane of the cavity of the tympanum; to the mastoid cells; to the muscle of the stapes, and to the external semicircular canal. One of these vessels anastomoses, in the upper and posterior part of the cavity of the tympanum, with a small twig derived from the artery of the dura mater. When it has arrived behind the ear, the Posterior Auricular Artery termi- nates upon the external ear and the parts contiguous to it. 7. The INTERNAL MAXILLARY ARTERY* Arises from the external carotid under the parotid gland, at a little distance below the neck of the condyloid pro- “ The general situation of this artery, and the distribution of se- veral of its most important branches, cannot be understood without a knowledge of the bones through which they pass. The student of surgery will therefore derive benefit from a re-examination of these bpnes, and of the zygomatic fossa, &c. when he studies this artery. 'See Vol. J. page 61 .) — -He ought to be well acquainted with this 237 The Internal Maxillary Artery. cess of the lower jaw, and extends to the bottom of the zygomatic fossa; varying its direction in its course. It is rather larger than the temporal. a. It first sends off one or two small branches to the ear , and a twig which penetrates into the cavity of the tympanum by the glenoid fissure. b. It also sends off a small artery called the Lesser M&ningeal , which passes upwards, and after giving branches to the external pterygoid and the muscles of the palate, passes through the foramen ovale, and is spent upon the dura mater about the sella turcica. c. It then sends off one of its largest branches, the ' .Great or Middle Artery of the Dura Mater, which passes in a straight direction to the foramen spinale, by which it enters into the cavity of the cranium. This artery ramifies largely on the dura mater, and makes those arborescent impressions which are so visible hr the parietal bone. It generally divides into two great branches: the anterior, which is the largest, passes over the anterior and inferior angle of the parietal bone: the posterior branch soon divides into many ramifications, which are extended laterally and posteriorly. It furnishes the twig which passes to the ear by the hiatus of Fallopius, and anastomoses with the small branches of the stylo mastoid artery. It also supplies some other small vessels which pass to the cavity of the tympanum by small foramina near the junction of the squamous and petrous portions of the temporal bone. d. The next branch sent off by the internal maxillary leaves it about an inch from its origin, and is called the Inferior Maxillary. It passes between the internal ptery- subject, if he should undertake the management of necrosis of the jaw bones; or of those fungous tumours, which sometimes originate in the antrum maxillare; as well as of several other complaints. 238 The Internal Maxillary Artery. goid muscle and the bone, and after giving small branches to the contiguous muscles, enters the canal in the lower jaw, in company with the nerve. This canal has a very free communication with the cellular structure of the jaw, and the artery in its progress along it sends branches to the respective teeth and the bone. At the anterior maxillary foramen, this artery sends olf a considerable branch, which passes out and anastomoses with the ves- sels on the chin, while another branch passes forward and supplies the canine and incisor teeth and the bone contiguous to them. Sometimes the inferior maxillary artery divides into two branches before it has arrived at this foramen. In* this case, one of the arteries passes out of the foramen, while the other continues to the symphysis. e. Two branches pass off to the temporal muscle, which originate at a small distance from each other: one of them passes upwards on the tendon of the temporal muscle; the other arises near the tuberosity of the upper maxillary bone: they are called the exterior deep y and the interior deep temporal artery . They are both spent upon the temporal muscle; but the interior branch sends a small twig into the orbit of the eye. f. There are some small branches which pass to the Pterygoid Muscles and to the Masseter , which arise either from the internal maxillary artery, or from the an- terior deep temporal. They are generally small, and often irregular. c. An artery, particularly appropriated to the cheek, perforates the buccinator muscle from within outwards, and generally terminates on the buccinator, the zygoma- ticus major and the muscles of the lips. This Artery oj the Cheelc is very irregular in its origin, sometimes aris- ing from the internal maxillary, sometimes from the deep temporal, and sometimes from the suborbitary, or from the alveolar artery, to be immediately described. The Internal Maxillary Artery. 239 h. The Alveolar Artery , or the Artery of the Upper Jaw , arises generally from the internal maxillary, but sometimes from one of its branches. It winds round the tuberosity of the upper jaw, and sends branches to the buccinator muscle, to the bone and the gums, to the an- trum highmorianum, and some of the molar teeth: and also to the teeth generally, by means of a canal which is analogous to that of the lower jaw. i. The Infra- orhitar Artery arises from the internal maxillary in the zygomatic fossa, and soon enters the infra orbitary canal, through which it passes to the face, and emerges below the orbit of the eye, supplying the muscles in the vicinity, and anastomosing with the small ramifications of the two last described arteries, and also of the facial artery and the ophthalmic. This artery in its course sends off small twigs to the periosteum, the adipose membrane, and the muscles in the inferior part of the orbit, and also to the great maxillary sinus or antrum highmorianum, and to the ca- nine and incisor teeth. j. The Palato Maxillary , or Superior Palatine Artery, arises also in the zygomatic fossa, and, descending be- hind the upper maxillary bone, enters the posterior pala- tine canal. It generally forms two branches, the largest of which advances forward, supplying the palate and gums, and finally sends a twig through the foramen in- cisivum to the nose, while the posterior branch, which is much smaller, supplies the velum pendulum palati. ic. The Pterygo Palatine, or Superior Pharyngeal , is a small vessel, which sometimes arises from the artery- next to be mentioned. It is spent upon the upper part of the pharynx, and a branch passes through the pterygo palatine foramen, which is spent upon the arch of the palate and the contiguous parts. l. The internal maxillary at length terminates in the Spheno- Palatine, or Large Nasal Artery, which 240 Temporal Artery. passes through the spheno-palatine foramen to the back part of the nose. This artery sometimes separates into two branches before it enters the foramen; sometimes it enters singly, and divides into two branches soon after; one of them is spread upon the septum, and the other upon the external side of the nose; each of these branches ramifies very minutely upon the Schneiderian membrane and its process in the different sinuses, and also in the ethmoidal cells. 8. The TEMPORAL ARTERY Is considered as the continuation of the external carotid, because it preserves the direction of the main trunk, al- though the internal maxillary is larger. After parting with the internal maxillary it projects out- wards; and passing between the Meatus Auditorius Ex- ternus and the condyle of the lower jaw, continues up- wards, behind the root of the zygomatic process of the temporal bone, to the aponeurosis of the temporal muscle: on the outside of which, immediately under the integu- ments, it divides into two large branches denominated anterior and posterior. Before this division the temporal artery sends off seve- ral branches of very different sizes. One, which is considerable in size, and called the Transverse Facial Branch , advances forwards across the neck of the condyle of the lower jaw, and giving small branches to the masseter, runs parallel to the parotid duct, and below it. This branch is spent upon the muscles of the face, and anastomoses with the other vessels of that part. The temporal gives off small branches to the parotid gland and to the articulation of the jaw. From the last mentioned branch small twigs pass to the ear, one of Temporal Artery. Internal Carotid. 241 which enters the cavity of the tympanum by the glenoid fissure. While this artery is on a line with the zygoma, it sends off a branch called the middle temporal artery , which penetrates the aponeurosis of the temporal muscle, and ramifies under it upon the muscle in an anterior direc- tion. The two great branches of the temporal artery are dis- tributed in the following manner. The Anterior passes up in a serpentine direction on the anterior part of the tem- ple, and supplies the front side of the head, and the upper part of the forehead. The Posterior extends upwards and backwards, and supplies the scalp on the lateral and middle part of the cranium, and also the bone. Ramifications from each of these branches anastomose on the upper part of the cranium with those of its fellow of the opposite side. The anterior branch also anastomo- ses on the forehead with the facial and ophthalmic artery; and the posterior branch with the occipital artery on the back part of the head. THE INTERNAL CAROTID ARTERY Is sometimes called the Artery of the Brain , as it is almost entirely appropriated to that viscus. From its origin to the commencement of its ramifica- tions the course of this bloodvessel is peculiarly tortuous. In consequence of which, the force of the blood in it is greatly diminished before it arrives at the brain. An instance of this curvature occurs immediately after its separation from the external carotid, when it pro- trudes outwards so much as to be exterior to that vessel; after this, it ascends to the carotid canal, and in its course is in contact, or very near the par vagum and intercos- tal nerves. Vol. IL 2H 242 Curvatures of the Internal Carotid. The carotid canal in the os petrosum is by no means straight; it forms a semicircular curve, forwards and in- wards; and its upper portion, which is nearly horizontal, opens obliquely against the body of the sphenoidal bone at a small distance from it. Therefore, after the artery has passed through the canal, it must turn upwards to get fairly into the cavity of the cranium; and of course, its direction while in the canal, forms almost a right angle with its direction before it enters, and after it emerges from it. In consequence of this curvature, much of the mo- mentum of the blood must be impressed upon the cra- nium. After the artery has arrived at the end of the carotid canal, and has turned upwards to get within the cavity of the cranium, it bends forwards, and passes nearly in a horizontal direction, through the cavernous sinus on the side of the sella turcica, to the anterior clinoid process; here it again forms a considerable curve, which is directly upwards, and then it perforates the dura mater. These curvatures must also deprive the blood of the carotid of a portion of the momentum which it has re- tained after leaving the bone. The object of these various flexures of the internal ca- rotid appears to be analogous to that of the Pete Mira- bile in certain quadrupeds, which is formed by the divi- sion of this artery into many small branches, that reunite again, without producing any other effect than the dimi- nution of the momentum of the blood. During its course from the place of bifurcation to its entrance into the carotid canal, the internal carotid arte- rv very rarely sends off any branches. In the canal it gives off a small twig which enters the cavity of the tym- panum; and sometimes a second which unites with the Pterygoid branch of the internal'maxillary. As it goes by the sella turcica, it passes through the 243 Ophthalmic Artery. cavernous sinuses, and gives off two branches which are called the Posterior and Anterior arteries of the Caver - nous Sinus or Receptacle. The posterior branch goes to that part of the dura ma- ter which is connected with the posterior clinoid process, and the cuneiform process of the occipital bone. It like- wise gives branches to several of the nerves which are contiguous, and to the pituitary gland. The anterior artery also gives branches to the conti- guous nerves, to the dura mater, and the pituitary gland. When the internal carotid turns upwards at the anterior clinoid process, it sends off the OPHTHALMIC ARTERY, Which passes under the optic nerve through the foramen opticum into the orbit of the eye, and is about two lines in diameter. Although this artery enters the orbit under the optic nerve, it soon takes a position on the outside of it; but afterwards gradually proceeds to the inner side of the orbit, crossing over this nerve in an oblique direction, and finally passes out of the orbit near the internal angle. In this spiral course it sends off numerous branches, viz. a. To those parts which are auxiliary to the eye. b. To the ball of the eye. c. To the cavity of the nose, through small foramina in the ethmoid bone, and d. To the forehead and external side of the nose. These branches generally go off in the following order. The Lachrymal artery arises soon after the ophthal- mic arrives within the orbit, and passes above the abduc- tor muscle to the lachrymal gland, where it terminates, sending off many small branches in its course. The Central artery of the retina also leaves the ophthal- mic soon after its arrival in the orbit: it is a small vessel 244 Branches of the Ophthalmic Artery . which penetrates into the center of the optic nerve, and passing with it into the eye is spread upon the internal surface of the retina. Here it appears to terminate in the adult; but in the foetus it is continued through the vitreous humour to the capsule of the crystalline lens. While the ophthalmic is passing over the optic nerve the branches which enter the ball of the eye leave it. Their number varies, but they form three classes, viz. The Long Ciliary , the Short Ciliary , and the Anterior Ciliary arteries. (See description of the eye, vol. i. p. 341.) The supra orbitary and muscular branches leave it also near the same places. The Supra Orbitary Branch often gives off several muscular twigs: but it passes out of the orbit through the supra orbitar foramen, and generally divides into two branches, one of which is spent upon the periosteum, and the other upon the-skin and muscles of the forehead. There are sometimes two muscular branches , a Superior and an Inferior. The superior branch is often deficient: when it exists it supplies the levator palpebrse, the levator oculi, obliquus superior, See.; but these parts are often supplied by the branches above mentioned. The supra orbitar so frequently gives off branches to the muscles that it has been called the Superior Muscular Branch. The inferior muscular branch is more constant. It commonly supplies the rectus inferior, the adductor, and the inferior oblique muscles, and also the lachrymal sac, and the low- er eyelid, &c. When the artery is on the inside of the nerve it sends off 'he two branches to the cavity of the nose, viz. The Ethmoidal Arteries; and also, branches to the eyelids. The Posterior Ethmoidal branch is first. It passes be- tween the levator and adductor muscles, and above the obli juus superior; and penetrates the cavity of the crani- um by the posterior orbitary foramen: after giving some twigs to the dura mater, it passes to the posterior cells Branches of the Ophthalmic Artery . 245 of the ethmoid by the foramina of the cribriform plate of that bone, and sends a small branch to the Schneide- rian membrane on the back part of the septum of the nose. The Anterior Ethmoidal artery arises from the ophthal- mic nearly opposite to the anterior orbitary foramen, through which it passes: and after entering the cranium is distributed like the other through some of the foramina of the cribriform plate to the anterior cells of the ethmoid bone, and to the anterior part of the Schneiderian mem- brane on the septum of the nose, to which it sends a considerable branch. In its course it sends twigs to the frontal sinuses, and to the dura mater and its falciform process. The arteries of the Palpebrce are called Superior and Inferior; they leave the ophthalmic near the loop or pully of the superior oblique muscle. The inferior comes off first; it sends branches to the ligaments of the tarsus, the caruncula lachrymalis, and the parts connected with the cartilage of the under eyelid, and unites with the lachry- mal artery near the external canthus, forming an arch called the Inferior Tarsal Arch. The Superior Artery supplies the superior part of the orbicularis muscle, the ligament and caruncula also: and it likewise unites with a twig of the lachrymal, and forms the superior tarsal arch. Soon after sending off the palpebral branches, the Ophthalmic Artery arrives at the internal canthus, and then finally divides into two branches, the nasal and the frontal. The Nasal Branch passes above the superior part of the lachrymal sac and the ligament of the eyelid to the nose; after sending a twig to the frontal muscle and the lachrymal sac, it passes down the side of the nose and anastomoses with the facial artery. The Frontal Artery is not so large as the nasal; it gene- rally divides into three parts. A superciliary branch which 246 Internal Carotid. Middle Artery of the Brain. is principally spent upon the eyebrows; a superficial branch which is spent upon the forehead; and a branch which is distributed to the pericranium. The INTERNAL CAROTID , soon after parting with the ophthalmic, sends off, in a posterior direction, a branch to join one from the vertebral artery. From its destination this vessel is called the arteria communicans. After this it sends off another branch, which is so large that it may be considered as a continuation of the main trunk: this is called the middle artery of the brain, or the arteria sylviana. It runs outwards nearly in the direction of the fossa Sylvii, which separates the an- terior from the middle lobes of the cerebrum. In its course it divides and subdivides into numerous branches which are spread upon the Pia Mater , and finally enter the surface of the brain in a very minute state. The internal carotid then terminates in a branch which is smaller than the last mentioned, and from its situation is called the anterior artery of the brain, or ar- teria callosa. This vessel first inclines towards its fellow on the opposite side, and after approaching within half an inch of it, forms another curve, and runs forward to the anterior part of the brain, dividing itself gradually into branches which pass in several directions. When these anterior arteries are nearest to each other, a small Transverse branch, which passes at right angles, connects them together. This branch completes the ante- rior part of the Circle of Willis. It crosses immediately before the sella turcica and pituitary gland, and sends off branches which pass to the third ventricle, to the fornix and septum lucidum, and also to the pia mater. The anterior arteries of the brain also send off branches to the optic and olfactory nerves; to the opposite surfaces of the two hemispheres on each side of the falx; to their inferior surfaces, and to the corpus callosum. They have likewise some branches which anastomose 247 Right and Left Subclavian Arteries. with those of the middle artery of the brain, and of the vertebral artery. The SUBCLAVIAN Arteries. The RIGHT SUBCLAVIAN may be considered as the continuation of the arteria innominata. This last mentioned artery, after leaving the aorta, forms a curve or arch, which extends obliquely backwards and out- wards, over the first rib to the axilla, crossing the trachea in its course. At the distance of an inch and a quarter, or an inch and a half from its origin, it sends off the right carotid, and then, assuming the name of Right Subclavian , continues in the above stated direction. The cord of the curve of this artery, and the cord of the curve of the aorta, are not in the same direction, but form an angle with each other. The position of the LEFT SUBCLAVIAN is some- what different from that of the right. Its origin is poste- rior, and, therefore, the direction of the cord of its curve is more immediately lateral. The curve or arch is also smal- ler. The situation of the two subclavians as relative to the contiguous parts, is, therefore, somewhat different; but each of them proceeds between the anterior and the middle scaleni muscles, and when they have arrived at these muscles, their respective positions are very similar. The anterior and middle scaleni muscles arise from the transverse processes of several of the cervical vertebras, and are inserted into the first rib, one before the other, so as to leave a considerable space between them. The sub- clavian arteries pass through this space, and before they arrive at it, but when they are very near the above men- tioned muscles, they send off several very important branches in various directions, viz. to the cavity of the cranium, to the parietes of the thorax, to the thyroid gland, and to the lower part of the neck. 248 Course and Distribution of the Inferior They proceed near to the scaleni muscles before they send off any branches; and it is to be observed, that the subclavian veins which correspond with these arteries, are anterior to them, for they pass before the scaleni muscles, and not between them. The internal mammary Artery Goes downwards, from the lower and anterior part of the subclavian, along the inner side of the anterior scalenus muscle. It proceeds, exterior to the pleura, across the car- tilages of the true ribs, and near their middle; and, con- tinuing between the cartilages and the diaphragm, exterior to the peritoneum, terminates on the rectus abdominis muscle, in branches which anastomose with those of the epigastric artery. In this course it gives branches to al- most all the parts to which it is contiguous, viz. to the muscles and glands at the lower part of the neck; to the thymus gland; to the parts in the intercostal spaces; to the sternum; to the mediastinum and pericardium; to the diaphragm and to the muscles of the abdomen. From some of its ramifications upon the parts between the ribs, small branches go off to the mamma, and thereby give a name to the artery. There is also a small vessel which is sent off by the mammary artery, or by one of its upper branches, which accompanies the phrenic nerve to the diaphragm. The inferior thyroid Artery Arises from the upper side of the subclavian nearly op- posite to the origin of the internal mammary. It passes upwards and inwards, between the carotid artery and the spine, to the thyroid gland: then it anastomoses with the Thyroid and the Vertebral Arteries. 249 branches of the superior thyroid on the same side, and with those of its fellow on the opposite side. This vessel sometimes sends off large branches to the muscles at the lower part of the neck. The vertebral Artery Arises from the upper and posterior part of the subclavian. It goes upwards and backwards between the muscles which lie on the front of the spine, and passing under the trans- verse process of the sixth or seventh cervical vertebra, enters into the canal formed in the transverse processes of the vertebrae. In this course, as it proceeds from the third to the second cervical vertebra, it inclines outwards laterally, and, in its passage from the transverse process of the second to that of the first vertebra, it forms a con- siderable curve, the convexity of which has a lateral and external aspect. After passing the transverse process of the Atlas , it is turned suddenly backwards, in a groove, and finally passes through the great occipital foramen into the cavity of the cranium. It then proceeds upon the cu- neiform process of the occipital bone, under the Medulla Oblongata , and joins its fellow so as to form an acute angle with it near the union of the medulla oblongata with the pons Varolii. From each of the vertebral arteries, before their union, there generally goes off a small branch called the Posterior Meningeal , which is spent upon the posterior part of the dura mater. The trunk formed by the union of the vertebral arteries is called The BASILAR Artery. It extends forward near to the anterior part of the pons Varolii, where it bifurcates; but previously sends off se- veral branches on each side. The first pair go off in a Vol. II. 2 I 250 Basilar Artery. lateral direction, soon after its commencement, near the back part of the pons Varolii, and are spent upon the me- dulla oblongata, the pons Varolii. and 'he other contigu- ous parts, and also upon the fourth ventricle and the Plex- us Choroides of that cavity. They are called the Posterior or Inferior Arteries of the Cerebellum. Two other lateral branches, which are called the Su - perior Arteries of the Cerebellum , go oft' from the basilar artery, near its anterior extremity. These are principally spent upon the crura of the cerebellum and cerebrum; upon the cerebellum itself, and the contiguous parts. Soon after sending oft’ the last mentioned arteries, the basilar artery divides into two branches, which also take a lateral direction, and are of considerable size. In their course outward, these branches are curved with their convexity forward. About ten or twelve lines from its commencement, each of them sends off a branch called the arteria communicans, which passes directly for- ward, and communicates with the internal carotid, thus forming the arrangement, which is called the Circle of Willis .* After sending off these arteries, they continue their lateral direction, and are distributed principally to the posterior parts of the cerebrum. These terminating branches of the basilar artery are called the Poste- rior Arteries of the Cerebrum. * The arteria communicans is also considered as a branch of the Internal Carotid. The arrangement here alluded to is very remark- able. As the branches which pass off laterally from the single trunk of the Basilar Artery unite to the Internal Carotids, and the Internal Carotids are united to each other, there is an uninterrupted conti- nuation of artery, which incloses a portion of space of a determined form; but this form resembles an oblong square more than a circle. By this connexion blood will pass from any one of the four arteries of the brain to all the others. Arteries of the lower part of the Neck. 251 The superior intercostal Artery Arises from the upper part of the Subclavian , after the Vertebral and Thyroid arteries, and very near them. It de- scends by the side of the spine across the first and second ribs, near their heads, and exterior to the great intercostal nerve . It generally forms two branches, which are ap- propriated to the muscles, & c., in the first and second intercostal spaces, and sometimes a small branch is con- tinued to the third intercostal space. From each of these branches a small vessel proceeds backwards, and is spent upon the contiguous muscles, &c., on the back of the thorax. The intercostal artery also sends a branch upwards to the deep seated parts of the neck. In addition to the arteries above mentioned, there are several others of considerable size, which originate either directly or indirectly from the SUBCLAVIAN ’ and are spent upon the lower portion of the neck, and the conti- guous parts. These arteries are very different in different subjects, especially as to their origin. Two of them, which have been called the anterior and posterior cervi- CALS,are generally distributed to the muscles and other parts which lie on the lower portion of the neck anteriorly and posteriorly. A third, which passes transversely on the lower part of the neck, is called the superior scapular. In some cases the two cervical arteries arise from the subclavian, after the mammary and the thyroid, in a common trunk, which soon divides. Very frequently they go off from the Inferior Thyroid. Sometimes one of them goes off from the Inferior Thyroid , and the other from one of the branches of the Subclavian .* * Haller paid great attention to the arterial system, and made many dissections, with a view to engravings of it, which he publish- ed with descriptions, in folio fasciculi. These 25 2 Branches that go off in the Axilla . The Superior Scapular most commonly arises with some other artery, and very often from the Inferior Thyroid. It runs transversely outwards, within and above the clavicle, and passing through the notch in the upper costa of the scapula, divides into branches which are dis- tributed to the parts on the dorsum of that bone. The SUBCLAVIAN ARTERY , in its progress from the aorta to the axilla, forms an arch or curve, over the first rib, as has been already observed. The anterior scalenus muscle is before it, and the great nerves of the upper extremity are above it. After passing between the scaleni it descends upon the first and second rib into the axilla. The nerves which were above, descend with it: at first they are necessarily exterior to it, but they form a plexus which the artery enters into, so as to be partly surrounded by them. This course of the artery is ob- liquely under the clavicle, and behind the pectoral muscle. In the axilla, the vessel and nerves which surround it are placed between the tendons of the pectoralis and the latissimus dorsi muscles. Here the artery takes the name of AXILLARY, and sends off several important branches. The principal branches that go off from the axillary artery are distributed 1st. Anteriorly, to the pectoral muscle, and the parts on the anterior surface of the thorax. 2d. Posteriorly, to the muscles which are on the sca- pula and contiguous to it; and 3d. To the parts which are near the upper extremity of the os humeri. These fasciculi have been collected, and, with some other engrav- ings, form a large volume, entitled ICONES ANATOMICJL, which is truly valuable. There are some very interesting observations on this work of Hal- ler’s, and also on these arteries, in a DESCRIPTION OF THE ARTERIES, by Dr. Barclay of Edinburgh, which I have read with advantage, as well as a work on the muscles by the same author. Branches that go off in the Axilla. 253 Anterior Branches. The arteries which go to the pectoral muscle, &c., are very various in different subjects, both as to their number, origin, and size. They have also been called by different names, as THORACIC AL, MAMMARI® EXTERNAL, be. There are almost always three of them, and very often more; one of them, which is called by several authors the Acromialis, proceeds towards the end of the clavicle, and generally passes out at the interval between the deltoid and the pectoral muscle, sending various branches to the contiguous parts; the largest of its branches often passing in the direction of the interstice between those muscles. Another of these arteries, which is called Superior Thoracic , is generally very small: it often is a branch of the above mentioned Acromialis. There is very often to be found here an artery called the Inferior Thoracic , or the External Mammary , which is of considerable length, although its diameter is not very great. This artery originates near the two last men- tioned, and sometimes from the Acromialis. It often ex- tends downwards as low as the sixth rib, and send branch- es to the anterior part of the thorax, to the mamma, and the other contiguous parts. Many of the small branches of this artery anastomose very freely with those of the in- ternal mammary. There are always small arterial branches in the axilla, which ramify upon the glands and adipose matter always existing there. They often arise by one common trunk, which is called the Axillary Thoracic. Posterior Branch. One large artery is commonly sent to the muscles on the scapula, which is called the scapular, the common 254 Branches that go off in the Axilla. scapular, or the internal scapular. It commonly passes off from the axillary after the thoracic arteries, and supplies the muscles on both surfaces of the scapula. This large vessel passes downwards a short distance in the direction of the inferior costa of the scapula, and soon sends off a branch that winds round to the dorsum of the bone, to be distributed to the infra spinatus and the con- tiguous muscles, which is called the Dorsalis Scapula. The main trunk then inclines to the subscapularis mus- cle, and generally divides into two branches, which are distributed to the subscapularis, teres major, latissimus dorsi, &c. Sometimes the scapular artery divides into two branches before it sends off the dorsal. In this case the last mentioned artery goes off from one of those branches. Branches near the Os Humeri. The arteries which are near the body of the os humeri at its upper end, are generally two in number, and deno- minated the Anterior and Posterior Circumjlexce. Some- times they arise separately, and sometimes in a common trunk from the AXILLARY artery. Frequently one of them arises from the scapular. The Anterior Circumflex passes between the united heads of the biceps and coraco brachialis muscles and the body of the os humeri, at a small distance below its head. It sends branches to the capsular ligament, the pe- riosteum of the os humeri, the membranes of the groove for the long head of the biceps, the upper portions of the biceps and coraco brachialis, and some contiguous mus- cles. The Posterior Circumflex proceeds between the sub- scapularis and teres major muscles, and continues be- tween the os humeri and the head of the triceps and the Situation of the Humeral Artery. 25 S deltoides. It is distributed to the muscles and parts about the joint, especially the deltoides. These arteries surround the Os humeri, and the small branches anastomose with each other. The Posterior Cir- cumflex is much larger than the Anterior. The great artery of the arm proceeds from the axilla to the elbow; and, during this course, is generally deno- minated The HUMERAL Artery .* ~ Its direction is influenced by the position of the os hu- meri. When the arm hangs down, with the palm of the hand presenting forward, this direction is somewhat spiral. The situation of the artery is on the inside of the biceps muscle, and between that muscle and the triceps extensor. It also continues very near and on the inside - of the tendon of the biceps, and under the Aponeurosis which proceeds from that tendon. In consequence of the spiral or oblique course of the artery, its direction would be from the inside of the tendon of the biceps to the ra- dial side of the fore arm, but soon after it passes across the joint of the elbow, it divides into two branches: one which preserves, for some distance, the direction of the Main Trunk , is called the radial artery: the other, which inclines obliquely downwards and towards the ulna, is the common trunk of the ulnar and in- terosseal arteries. During this course, the HUMERAL artery sends off several branches to the muscles and other parts on the os humeri. The largest of them is denominated the Pro- * funda Humeri , or Spiralis. This artery very often arises as high as the insertion of the latissimus dorsi, and pass- ing between the heads of the triceps extensor muscle, * It is also called Brachial Artery by several writers. 256 Branches of the Humeral Artery. proceeds downwards under that muscle, in a spiral di- rection, towards the external or radial condy le. If sends several branches to the triceps and ;he contiguous mus- cles, and one considerable branch, which is generally • called the Profunda Minor , to the pai fs contiguous to the internal condyle. The ramifications of these branches near the condyle frequently anastomose with small branches of the radial and ulnar arteries.,* A small branch frequently arises from he humeral artery, at a short distance from the Profunda Humeri , which sends a ramification to the medullary foramen of the os humeri. This vessel is, therefore, denominated Arteria Nutritia. There are very often several anastomoses between the branches of the HUMERAL artery, which originate above the elbow, and certain branches of the radial and ulnar arteries, Which are called from their direc- tion recurrents. Among these arteries there is generally one of considerable size, which proceeds across the elbow joint near the internal condyle. Sometimes this is the ulnar recurrent, which goes up to anastomose with the branches of the profunda; but more frequently it is a separate branch of the HUMERAL artery, which goes off a little above the elbow, and passes across the articu- lation, near the internal condyle, to anastomose with the branches of the ulnar artery. This artery is denominated the Anastomotica. There are often other branches sent off by the HU- MERAL artery; but they are commonly small, and very irregular. The two great ramifications of the HUMERAL artery on the fore arm have very different directions. The ra- * The Profunda sometimes originates from the scapular, or one of the circumflex. The profunda minor sometime* has a distinct and separate origin, lower down than the other. Course ana Ramifications of the Radial Artery. 257 dial artery preserving the course of the main trunk, while the common trunk of the ulnar and interos- seal projects from it in a direction downwards and to- wards the ulna, passing under the pronator teres, &c. The radial Artery , Passing over the pronator teres muscle, proceeds be- tween the supinator radii longus and the flexor carpi ra- dialis, very near to the lower end of the radius, without changing its direction materially, being deep seated above and superficial below; it then alters its course, and, passing under the tendons of the extensors of the thumb, to the back part of the radius, it continues be- tween the metacarpal bones of the thumb and of the index finger, when it divides into three branches. In this course it gives off but few branches. The first is the Radial Recurrent , which passes upwards and to- wards the external condyle, and frequently anastomoses with the ramifications of the profunda humeri. The branches which it sends off between the origin of the recurrent and the lower end of the radius are gene- rally very small, and distributed to the parts immediately contiguous to the artery. Before it turns under the ten- dons of the extensors of the thumb, it sends a branch over the waist towards the root of the thumb, from which proceeds a branch to anastomose with the volar branch of the ulnar; and another, not so large, which is frequently continued on the radial or external side of the thumb, very near to its extremity. While the radial ar- tery is under the aforesaid tendons, it sends off small branches to the back of the wrist and back of the hand, and often to the back of the thumb. Those which are distributed to the wrist and back of the hand, generally anas omose with the small branches of the ulnar and interosseal arteries. Vol. II. 2 K 258 Origin of the Ulnar and Interosseal Arteries. The three branches into which the radial artery divides between the metacarpal bones of the thumb and index are, 1st. a branch to the external side of the index; 2dly, a branch to the thumb , that sometimes divides into two which pass up on the anterior or volar surface, and sometimes continues, without much diminution, on the internal side of the thumb, near to the end of the last phalanx; and, 3dly, a branch, called Palmaris Profunda , which dips down into the palm of the hand, and, pro- ceeding in contact with the metacarpal bones, under the flexor tendons, &c., forms an arch which extends across the hand, and often terminates by anastomosis with ano- ther arch, soon to be described, which is formed by the ulnar artery. This flexure, which is denominated Arcus Profundus , sends off branches of a very small size, which are distri- buted to the bones, ligaments, muscles, See., contiguous to it. The common trunk o/ the ulnar and interosseal Arteries Passes under several of the muscles which originate from the internal condyle, and between the flexor sub- limis and the flexor profundus. Before the Ulnar Recur- rent goes off from this vessel, the interosseal artery often leaves it. This recurrent artery passes upwards be- tween the muscles of the internal condyle, and distributes branches among them. It then passes up in the groove behind the internal condyle, and anastomoses with the branches of the Anastomotica or Profunda Humeri. The ulnar and interosseal arteries separate from each other at the distance of fifteen or twenty lines from the origin of the radial artery, very near the commence- ment of the interosseal ligament. Interosseal and Ulnar Arteries. 259 The interosseal Artery , In a majority of cases arises in a single branch from the common trunk of the ulnar and interosseal. When it does so, the single branch soon sends off the Posterior Inter- osseal artery, which perforates the interosseous ligament, and passes down on its posterior surface, while the main branch continues on the anterior surface of the ligament, and is denominated the Anterior Interosseal Artery . In some cases the main branch proceeds on the anterior surface as low as the upper edge of the pronator qua- dratus muscle, before it sends off the posterior branch. Sometimes the anterior and posterior interosseals arise separately. In this case the posterior soon perforates the ligament. The Anterior Interosseal passes down almost in com tact with the ligament, and gives branches to the con- tiguous parts in its course. It generally perforates the in- teroseous ligament near the wrist, and sends off many small branches to the back of the wrist and hand, which anastomose with the small branches of the radial and the posterior interosseal arteries. The Posterior Interosseal soon gives off a recurrent or anastomosing branch, and then proceeds downwards to- wards the wrist, sending branches in its course to the extensor muscles and tendons. This vessel sometimes divides into two branches. The ulnar Artery. The ulnar artery proceeds among the muscles ob- liquely downwards, and is not superficial until it has ar- rived within three or four inches of the carpus: it then continues towards the hand, sending off very small branches in its progress. It passes over the annular liga- 260 Course of the Ulnar Artery , and ment at the wrist, and winds round the pisiform bone: here it is supported by a delicate ligament, which seems to lie upon it: from this it passes upon the palm of the hand, under the aponeurosis palmaris, and over the ten- dons of the flexors of the fingers. When thus situated, it forms, in perhaps a majority of subjects, an arch or bow, called arcus sublimis, which extends across the palm of the hand, from the ulnar towards the radial edge, and, after sending branches to the fingers, &c., from its con- vex side, terminates near the root of the thumb, by an- astomosis with that important branch of the radial ar- tery, which passes up on the inside of the thumb. The arcus sublimis almost always sends off small branches to the integuments, &c., on the palm of the hand. It often sends off, near the root of the metacarpal bone of the little finger, a branch which passes between the flexor tendons and the metacarpal bones, and anasto- moses with the Arcus Profundus. It then generally sends off a branch to the inner or ulnar side of the little finger; and afterwards three branches in succession, which pass from its convex side towards the angles formed by the fingers. These are called The Digital Arteries. When they have arrived near to the heads of the first phalanges of the fingers, each of these arteries divides into two branches, one of which passes along the side of one of the fingers to its extremity, and the other on the opposite side of the next finger: and in this way they pass on the sides of all the fingers, except the inside of the little finger and the outside of the index. These branr hes of the digital arteries are called Digito Radial and Digito Ulnar arteries, according to the sides of the fingers on which they are placed. They are situa- ted on the angle, if it may be so termed, which is formed Its Ramifications on the Hand and the Fingers. 261 by the anterior and lateral surfaces of each finger. In their course from the basis to the extremity of the finger, they send off" very small transverse branches, which an- astomose with each other, especially near the other. Some transverse branches are observable on the posterior as well as the anterior surfaces. Near the extremity of each finger, beyond the insertion of the flexor tendon, the ex- tremities of these arteries ramify minutely. Some of these small branches go to the skin, and others anasto- mose with their fellows of the opposite side. Some also go to the back of the fingers.* * The distribution of the radial and ulnar arteries in the hand, is very different in different subjects. Upon examining a large number of injected preparations in Phi- ladelphia, it was found that, is a very small majority of them, the ulnar artery formed an arcus sublimis, whose branches extended as far as the ulnar side of the index, and sometimes beyond it. That, in near a third of the preparations, the ulnar artery ramified without forming an arcus, and supplied only two of the digital branches, viz. the first two on the ulnar side. In such cases the radial artery generally made up the deficiency of the ulnar, but in a few in- stances the interosseal was extended on the palm of the hand, and supplied the radial side of the middle finger and the corresponding side of the index. In a few instances also the ulnar artery was still more deficient, and the radial was proportionally extended. 262 Bronchial Artery . SECTION III. Of the Branches which go off between the arch and the great bifurcation of the AORTA. PART I. In the Cavity of the Thorax. THE aorta sends branches to the Lungs , to the oeso- phagus, and to the parietes of the thorax. The bronchial Arteries Are the vessels which go from the aorta to the ramifica- tions of the trachea, and the substance of the lungs. They are not large, and are very irregular as to number and ori- gin. In a majority of cases the right lung is supplied, in part, by a branch from the first aortic intercostal of that side; while the left lung receives two or three branches from the aorta directly. In some cases a large vessel arises from the aorta, which divides into two branches, one of which goes to each lung. The bronchial arteries frequently send small branch- es to the posterior mediastinum, the pericardium, &c. Injections have shown, that there is a direct communi- cation between these vessels and the branches of the pulmonary artery. The Oesophageal Arteries Are very small vessels, which generally arise from the aorta, but sometimes are branches of the bronchials or intercostals that are spent upon the oesophagus. They occur in succession, and sometimes are five or six in intercostal Arteries, 263 number. They also send twigs to the contiguous parts, and the lowermost often descend to the stomach. The Inferior Intercostals Are the arteries which proceed directly from the aorta . to the parietes of the thorax. Their name is derived from their position between the ribs. They are ramified on the intercostal muscles and ribs, and on the pleura and some of the contiguous parts. They are called Inferior or Aortic Intercostals , to distinguish them from the superior intercostals, which are derived from the subclavian artery. Their number varies from ten to eight, according as the superior intercostals are more or less numerous. They originate in pairs on the posterior surface of the aorta.- The uppermost of them pass obliquely upwards, and the lowermost nearly in a horizontal direction, to the lower edges of those ribs to which they are appro- priated. They meet the rib near its tubercle, or place of junction with the transverse process of the vertebra, and then proceed forward, between the internal and external intercostal muscles, in a superficial but large groove, which is generally to be found on the interior margin of the low r er surface of the rib.* There is necessarily a differ- ence in the length of the right and left intercostals, owing to the position of the aorta, which is rather on the left of the spine. In consequence of this circumstance, the oeso- phagus is anterior to, and also in contact with those of the right side. They generally send off an important branch, called the Dorsal , which arises near their origin, and, passing backwards, sends ramifications to the muscles of the back. From this dorsal branch also proceeds a ramifica- tion, which enters the spinal cavity, and is spent upon its membrane and upon the medulla spinalis. * See Vol. I. page. 83. 264 General Account of the After the intercostals, in their progress forward, have passed beyond the middle of the ribs, they send off a branch, which generally proceeds very near to the upper side of the lower rib. The main trunk generally leaves the lower edge of the rib when it has arrived within one third of the length of the bone from its anterior extre- mity. It then generally divides into several branches, some of which are spent upon the pleura, and others on the intercostal and the contiguous muscles. According to the situation of the different intercostals, some of their ramifications communicate with those of the internal and external mammaries, of the phrenic, the lumbar, or the epigastric arteries. PART II. In the Cavity of the Abdomen . The AORTA passes into the cavity of the abdomen between the crura of the diaphragm, as has been already mentioned. In its course from the crura to its great bi- furcation, it sends off one pair of small arteries, called Phrenic , to the diaphragm. Three single arteries, the C CELIAC, the SUPERIOR, and the INFERIOR mesenteric, to the viscera of the abdomen. A pair of large arteries, the EMULGENTS, to the kidneys, with several that are very small to their appendages; as the Spermatics, Capsular , the Ureteric , and the Adipose . In addition to these, there is one pair of small arteries that go to the testicles, or to the ovaria and the uterus, and four or five pair, called lumbar arteries, that go off laterally, like the intercostals, to the parietes of the abdo- men, and to the muscles, &c., on the back, which are contiguous to them. Arteries of the Abdomen . 265 The phrenic Arteries Are ramified on the concave surface of the diaphragm, and are almost always two in number; they are denomi- nated right and left from their position. They commonly originate separately from the aorta, but sometimes they arise in a common trunk which soon divides. In some instances they are derived from the coeliac. In a few cases the aorta furnishes one, and the cceliac the other. Each of the phrenic arteries commonly crosses the crus of the diaphragm on its respective side, and proceeding laterally, in a circular direction, often ramifies so as to form an internal and external branch. Each of them generally sends branches to the cardia or oesophagus, to the glandulse renales, and other contiguous parts. The CCELIAC Artery Is the first great branch given off by the aorta in the abdomen, and is distributed almost entirely to the sto- mach, the liver, and the spleen. It projects from the ante- rior part of the aorta so as to form a right angle with it, and is of course nearly horizontal when the body is erect. The main trunk of this great artery is so remarkably short, that it has been compared to the stump of a tree: for at the distance of half an inch from its origin, it ge- nerally divides into three branches, which pass to the stomach, the liver, and the spleen, and are, therefore, de- nominated the gastric or coronary, the HEPATIC and the SP LENIC arteries. The first mentioned branch may be called 2 L VOL. II. 266 Distribution of The SUPERIOR CORONARY Or GASTRIC ARTERY, To distinguish it from other branches, soon to be describ- ed. It is commonly in the center of the three great rami- fications of the cceliac, and is also the smallest of them. It proceeds from its origin to the upper orifice of the stomach or cardia, and continues thence along the lesser curvature of that viscus, until it approaches near to the pylorus. In this course it sends branches to the oesophagus, which frequently inosculate with the oesophageal arteries. It also furnishes branches to the cardia, which partially surround it; and on this account, the artery has been called Co- ronary. Some of these last mentioned branches are often continued on the great extremity of the stomach, and anastomose with those ramifications of the splenic artery, called Vasa Brevia. It continues on the lesser curvature between the laminae of the small omentum, and sends off successively branch- es which pass between the peritoneal and muscular coats, and are distributed to the anterior and posterior surfaces of the stomach, communicating with the branches of the inferior gastric arteries, soon to be described.* The HEPATIC Artery Proceeds from the great ramification of the coeliac to the transverse fissure of the liver called the Porta , in which it generally divides into two branches. In this course it very frequently sends off an artery to the pylorus, which ramifies about the small extremity of the stomach, and often inosculates with some of the branches of the supe- rior coronary. This branch is called the Pylorica , and sometimes it arises from the artery' next to be mentioned. * This artery sometimes sends a branch to the liver. When this is the case, it is always very large. the Cceliac Artery. 267 The GASTRICA INFERIOR, DEXTRA, Which also generally originates from the main trunk of the hepatic, but sometimes from one of its branches. It is an artery of considerable size, which proceeds along the great curvature of the stomach, from the pylorus towards the great extremity, between the laminae of the anterior portion of the omentum, and distributes its ramifications to both sides of the stomach, and also to the Omentum. In its progress from the hepatic artery to the stomach, it sends off branches to the Duodenum , and to the right end of the Pancreas. The two great branches into which the HEPATIC . arterv divides are denominated right and left, from the lobes of the viscus, to which they are respectively appropriated. The right branch is the largest. Before it penetrates the substance of the liver, it sends off a branch to the gall bladder, called the Cystic Artery. The branches of the hepatic artery ramify very minutely in the liver, as has been stated in the account of that organ. The last great branch of the cceliac is The SPLENIC Artery , Which is generally supposed to be larger than the hepatic in adults, although it is less in children. It proceeds in a transverse direction from its origin to the spleen: its course is not straight, but meandering or serpentine. It is situated behind and above the pancreas, and passes along the groove in the upper edge of that viscus. In its progress, it sends off’ many small branches, and one that is of considerable size, to the Pancreas. It also sends one branch to the left extremity of the stomach, which arises commonly from the main trunk, but sometimes from the ramifications, which are soon to be mentioned. This branch, which is called 268 Distribution of the Splenic The CASTRICA INFERIOR SINISTRA, Is sometimes, but not often, very large: Its course is from left to right. It is situated between the laminae of the anterior portion of the omentum. It sends some small branches to the omentum, and others which are larger and more numerous, to both sides of the stomach. Some of these last mentioned anastomose with the ramifications of the gastrica dextra, which come from the hepatic. When the SPLENIC artery approaches near to the spleen, it divides into four, five, or six branches, each of which penetrates into that viscus by a distinct foramen, and then ramifies in the manner described in the account of the structure of the spleen.* Either from the splenic artery, or from these ramifica- tions, four or five branches pass to the large extremity of the stomach, and ramify there, communicating with the vessels already described. — These arteries have received great attention from physiologists, and are denominated Vasa Brevia, The SUPERIOR MESENTERIC, Which is the second great branch given off in the abdo- men by the aorta, is not very different in size from the coeliac, and originates about half an inch below it. It is distributed to the small intestines; to that portion of the great intestine, which is situated on the right side of the abdomen; and to the arch of the colon. From its origin it proceeds downwards, under the pancreas, and over the- lower portion of the duodenum, to the commencement of the mesentery. When it has arrived between the la- * It frequently happens that the splenic artery divides only into two or three branches, and they subdivide so as to form five or six, which penetrate the spleen, and the Superior Mesenteric Arteries. 269 minae of that membrane, it descends in a direction which corresponds with that of the root of the mesentery,* and forms a gentle curve, with its convexity directed towards the intestines. It necessarily diminishes as it descends, and generally terminates by anastomosing with one of its own branches.-— This great artery sends off some very small ramifications to the pancreas and the duodenum, while it is in their vicinity. It also sends two or three branches to the transverse part of the colon, to the right portion of the colon, to the beginning of the great intes- tine, and the contiguous portion of the ileon. These branches are commonly termed the colica media, co- l i c a dextea, and ileo conic a. From the convex side of the curve, the SUPERIOR MESENTERIC sends off the important branches which pass between the laminae of the mesentery, and supply the Small Intestines. These branches are numerous, and many of their ramifications anastomose with each other so as to form arches. From these arches go off other branches, which anastomose again with some of similar origin; and this process is re- peated successively several times, so that a net-work of bloodvessels seems to be formed on the mesentery. From the mesentery the small ramifications are continued in great numbers to the intestines. Some of them anasto- mose with each other on the coats of the intestine; but an immense number of minute arteries are continued to the villous coat, so that, when they are successfully in- jected, the surface of that coat appears uniformly co- loured by the injection. j- * See Vol. II. page 1 14. t See the account of the termination of these arteries, at page 104 of this volume. 270 Distribution of the Inferior Mesenteric. The INFERIOR MESENTERIC Artery Does not go off from the aorta next in order after the superior mesenteric, but succeeds it immediately on the intestines, and continues the arterial ramifications to the left portion of the colon , to which the branches of the superior mesenteric do not extend. This artery arises between the origin of the emul- gents, and the great bifurcation of the aorta, and pro- ceeds downwards, inclining to the left, but keeping near to the aorta. There are generally three branches distri- buted to the left portion of the colon, which arise from this artery, either separately, or by a common trunk which soon divides. It frequently happens, that one of these arteries arises separately, and two by a common trunk. These are called the left colic arteries; and are also sometimes denominated, from their position, SUPERIOR, MIDDLE, and INFERIOR. The SUPERIOR generally anastomoses with that branch of the superior mesenteric, which is called colica media, and forms a remarkable arch, called the Great Mesocolic Arch. The ramifications of the other branches frequently anas- tomose with each other, and are finally spent upon the left portion of the colon. The main trunk, diminished by sending off these branches, but still of considerable size, runs downwards on the posterior part of the intestine rectum, between that intestine and the sacrum, where it often divides into two branches, which continue near to the termina- tion of the rectum. From them proceed many ramifica- tions that are spent upon the rectum. Some of these ra- mifications anastomose with each other, and others with the ramifications of the hemorrhoidal artery, soon to be mentioned. Arteries of the Kidneys and Renal Glands. 271 The EMULGENT or RENAL Arteries Are the large vessels which pass from the aorta to the kidneys. They arise between the superior and inferior mesenteries, one on each side; and proceed in a direc- tion which is nearly rectangular to the aorta. The right emulgent artery is necessarily longer than the left, and it generally passes behind the vena cava. When they ap- proach near the concave edges of the kidneys, each emulgent commonly divides into three or four branches, which pass into the fissure of that organ, and ramify in the manner described in the account of it. Sometimes two arteries proceed from the aorta to the kidney: but this is not a frequent occurrence. The Capsular Arteries Are the small vessels which pass to the glandular re- nales. There are almost always several of them appro- priated to each gland. They often arise on each side from the coeliac artery, the aorta, and the emulgent. The Adipose Arteries Supply the adipose substance surrounding the kidneys.—* There are several of them on each side, and, like the last mentioned arteries, they are very small, and arise from several sources as well as the aorta. The testicles and ovaria are supplied by the Spermatic Arteries , Which are very remarkable for their great length and small diameter. In a majority of cases these vessels arise from the anterior surface of the aorta, a little below the 272 Spermatic Arteries. emulgents: but it often happens that the left spermatic arises from the emulgent on that side. They also some- times arise from other neighbouring arteries. It has been observed when they arise from the aorta, that the origin of one of them is generally higher than that of the other. They pass downwards, so as to form an acute angle with the aorta, and proceed behind the peritoneum, and before the psoas muscle and ureter. While this artery is in contact with the psoas muscle, it meets with the rami- fications of the spermatic vein , and, in its progress to the abdominal ring, also joins the spermatic cord. In this course it sends off some very small twigs to the conti- guous parts, and others that anastomose with similar ramifications from the mesenteric, epigastric, &c. Before it arrives at the testicle, it divides into several branches, two of which generally go to the epididymis, and the others penetrate the upper and back part of the tunica albuginea. The Spermatic Arteries in the Female , Instead of passing to the abdominal ring, proceed between the laminae of the broad ligaments, and send branches to the ovaria, which, in some cases, may be traced to the vesicles. They also send branches to the fallopian tubes and uterus, and to the round ligaments. Those which are on the opposite sides of the uterus, anastomose with each other and with the branches of the hypogastric arteries. The lumbar regions are supplied with arteries, which originate, like the intercostals, from the posterior part of the aorta between the thorax and pelvis. There are four or five of these vessels on each side, and they are deno minated Arteries above and at the bifurcation of the Aorta . 273 The Lumbar Arteries: They pass between the spine and the psoas muscles, and send branches to the spinal cavity, to the muscles of the lumbar regions, and the abdominal muscles. They anasto- mose with the internal mammary, the epigastric, the cir- cumflex of the ileum, &c. A small artery passes off singly from the posterior part of the aorta at its bifurcation, which is called The Middle Sacral Artery. It proceeds down the middle of the sacrum to the os coccygis, and sends off lateral branches, which are spent upon the contiguous parts, and inosculate with the arterise sacrse laterales. SECTION IV. Of the Arteries which originate at and below the Great Bifurcation of the Aorta. The PRIMITIVE ILIACS Form an acute angle with each other. They proceed downwards behind the peritoneum, very near the margin of the pelvis, without sending off any branch of impor- tance. At the junction of the sacrum with the ossa ilea, they divide into two great branches: the INTERNAL ILIAC , or HYPOGASTRIC , which descends into the pelvis; and the EXTERNAL ILIAC , which passes under the qrural arch to the lower extremity. Vol. If. 2 M 274 General Account of the Internal Iliac. The INTERNAL ILIAC , or HYPOGASTRIC , Is distributed, in part, to the viscera of the pelvis and the organs of generation, and also to the large muscles ex- terior to the pelvis: it is, therefore, very large, although not quite equal to the EXTERNAL ILIAC. It has already been mentioned, that in the foetal state, this vessel appeared to continue in a curved direction from its origin to the lower part of the side of the bladder, and from thence to the umbilicus, under the denomination of the Umbilical Artery. From the convex side of this curve the different branches of the internal iliac go off. In the foetal state they are very small in proportion to the umbilical artery; but as the artery becomes ligamentous, these branches increase in size. In the adult, the arrangement of these vessels is very different. The INTERNAL ILIAC generally divides into two great branches: the gluteal, which passes through the sacro sciatic notch, and ramifies on the ex- terior and upper part of the os ileum; and the ischiatic, which passes downwards on the outside of the tuberosity of the ischium. The first of these large ramifications passes out of the pelvis above the pyriform muscle, and the last of them below it. Several smaller arteries arise from these branches near their origin, or from the main trunk of the internal iliac, which are distributed to the different parts of the pelvis; and one important branch of the ischiatic, called the pudic, proceeds downward on the inside of the tu- berosity of the ischium. The first of the smaller branches which the internal iliac commonly sends off, is called the Smaller Branches of the Internal Iliac. 275 Ileo Lumbalis: It sometimes arises from the gluteal artery, and some- times from the main trunk of the internal iliac. It passes outwards under the psoas muscle, and suddenly divides into two branches. One of them proceeds upwards, and is distributed in the lumbar region, while the other rami- fies on the iliacus internus muscle, and is spent on the contiguous parts. There are also two or three small arteries called Arteries Sacra Later ales, Which sometimes arise singly, and sometimes in com- mon, from the great trunk. They also occasionally origi- nate from the gluteal artery. These vessels enter the an- terior foramina of the os sacrum, to be distributed on the cauda equina and the membranes which invest it. Some of their ramifications anastomose with branches of the sacra media and other contiguous arteries. On the anterior side of the internal iliac, near the origin of the above mentioned vessels, a ligament which was originally the umbilical artery, goes off to the side of the bladder, and continues from thence to the umbilicus. Sometimes it continues pervious for a short distance, and then small branches pass from it to the bladder. In the female it also sends small branches to the uterus and vagina. In addition to these Vesical Arteries derived from the umbilicals, there are other branches distributed to the bladder, which arise very differently, in different subjects, from branches which are soon to be described, as the he- morrhoidal, pudic, &c. From the anterior side of the internal iliac, or from one of its great branches, an artery often arises which passes 276 Smaller Branches of the Internal Iliac . out of the pelvis through the aperture in the margin of the ligamentous membrane which closes the foramen 'thyroideum of the os innominatum; this is called the Obturator Artery. * This vessel, while it is in the pelvis, often sends small branches to the bladder and its appendages, and to the obturator internus muscle. After it passes out of the pelvis, it frequently divides into branches; some of which are spent on the obturator externus, and the contiguous muscles, and others go to the hip joint. The origin of this artery is variable. Most commonly it arises from the internal iliac, but often from the ischiatic, and sometimes from the gluteal. In some instances it originates in a way that is particularly interesting when the operation for crural hernia is to be performed, viz. from the epigastric artery, soon to be described: for in this case the obturator artery sometimes nearly surrounds the neck of the hernial sac.* A small artery passes from the internal iliac or one of its branches, to the rectum, which is called the Middle Hemorrhoidal, From its situation between the branches which are sent to that intestine from the inferior mesenteric, and those which go to it from the pudic. This artery is spent upon that part of the rectum, which is above and in contact with the sphincter. It sends branches to the prostate and vesiculae seminales in males, and the vagina and bladder in females. In females there is a peculiar artery, * See Astley Cooper’s great work on Hernia, Vol. I. There is reason to believe that this position of the artery occurs more frequently than has been supposed. Larger Branches of the Internal Iliac. 277 The Uterine , Which originates either from the internal iliac, near the origin of the ischiatic, or from one of its branches. It passes between the laminae of the broad ligaments to the cervix uteri, and penetrates the texture of that organ. The size of this vessel varies with the varying size of the uterus. The gluteal or posterior iliac Artery , ’ One of the two great branches of the internal iliac, pro- ceeds exteriorly through the sciatic notch above the pyri- form muscle, very near the edge of the bone. On the out- side of the ilium it generally divides into two branches, one of which ramifies between the gluteus inedius and minimus, and the other between the medius and maximus. It is principally spent upon these muscles, and sends branches to the contiguous parts. The ischiatic Artery , The other great branch of the internal iliac, passes through the sciatic notch below the pyriform muscle, and proceeds downwards, between the great trochanter of the os femoris and the tuberosity of the ischium, under the gluteus maximus muscle. Soon after its origin, it commonly sends off a considerable branch, the Arteria Pudica, which also passes downwards: it then continues its course as above mentioned, and its principal branches are distributed to the gluteus maximus and the muscles of the upper and back part of the thigh, while its smaller branches go to the os sacrum and coccyx, and the contiguous small muscles. 278 Pudic Artery. The PUDICA INTERNA, » As has been just mentioned, is often a branch of the ischiatin artery, but sometimes originates immediately from the internal iliac. It proceeds downwards and in- wards, diverging from the ischiatic, and passing between the two sacro sciatic ligaments to the interior side of the tuberosity of the ischium, whence it continues on the inside of the crus of the os ischium and pubis until it approaches the symphysis, when it generally divides into three branches, which are spent upon the organs of gene- ration, from which circumstance the name of this artery » is derived. One or more branches from it also pass to the lower part of the rectum and sphincter ani, and are called the Lower Hcemorrhoidal Arteries. In its course it sends off many small branches to the contiguous parts; one of which, called the Perineal , leaves it near the transversus perinei muscle, and passes between that muscle and the skin, and between the bulb of the urethra and the crus of the penis, to the scrotum. When the pudic has arrived near the bulb of the urethra it sends a branch into it, which is continued into the corpus spongiosum urethrae, and ramifies there mi- nutely. At the symphysis of the pubis, it sends off a second branch, which passes to the back of each crus, and, pro- ceeding along it, parallel to its fellow, terminates in the glans penis: in this course it sends branches to the elastic coat, to the integuments, and to the prepuce. This vessel is called the Arteria Dorsalis. The main trunk of the pudic artery then penetrates the corpus cavernosum, and proceeds through it in a straight direction. Its ramifications appear to be distributed through the internal structure of the corpus cavernosut?!, External Iliac. Branches of the External Iliac. 279 and some of them extend through the septum to the other side, while others pass to the corpus spongiosum urethras. The EXTERNAL ILIAC, The great artery of the lower extremity, appears soon after birth, like a continuation of the primitive iliac, and proceeds along the brim of the pelvis behind the peri- toneum, to Poupart’s ligament or the crural arch, under which it passes. The psoas muscle is at first in contact with it on the outside, and the internal iliac vein on the inside. As it passes under Poupart’s ligament, it is immediately ante- rior to the psoas and iliacus internus muscles where they are united, and the crural nerve is exterior to it. Before it arrives at the lower edge of Poupart’s ligament, it sends off The Epigastric Artery , Which arises on its internal side, and proceeds down- wards and inwards about half an inch, then it turns up- wards and inwards, and continues in that direction for a small distance, after which its course is less oblique. It passes between the peritoneum and the abdominal mus- cles, behind the spermatic cord, and the round ligament in females. It generally changes its oblique direction after passing about two inches, and then proceeds in contact with the rectus, and very near its external edge. Its ramifications are expended upon the anterior parietes of the abdomen; and, after it has arrived as high as the umbilicus, it com- . monly divides into branches, which often inosculate with the ramifications of the internal mammary.* * Several respectable surgeons have been taught by experience, that when the abdomen is distended by ascites, the position of the 280 General Account of the Femoral Artery. An artery, which is rather smaller than the epigastric, arises nearly opposite to it, but rather lower, from the external side of the external iliac. It is called The Circumflex Artery of the Os Ilium, And proceeds upwards and outwards to the upper margin of the os ilium, along which it continues very near to the spine. It is distributed principally to the abdominal mus- cles, to the iliacus internus and the psoas, and the parts contiguous. The artery of the lower extremity, after passing under Poupart’s ligament, takes the name of FEMORAL Artery , And proceeds downwards in a direction so spiral, that although it is in front at the upper part of the thigh, it is completely behind at the lower part. It sends branches to the muscles of the thigh, as the aorta does to the viscera of the abdomen, viz. by a few large vessels which extend and ramify to a great distance among them. The situation of the adductor muscles, and their attach- ment to the os femoris, is such, that the artery in this course must necessarily perforate their common tendon, which it does at the distance of one third of the length of the bone from its lower end. The aperture in this tendon corresponds precisely with the general course of the artery; and before the artery enters this perforation, it is on the internal side of the bone; after it has passed the perforation, it is on the posterior side of it. After passing through the tendon of the adductors, it is denominated epigastric artery is so much altered, that it will sometimes be found in the middle of the oblique line, which extends from the umbilicus to the superior anterior spine of the ileum. Profunda and Circumflex branches of the Femoral. 281 The Popliteal Artery , and it retains this name until it divides. It then proceeds downwards, being very near the bone, and between the tendons of the flexors of the leg, covered by the great nerve of the lower extremity, and very often also by the vein. After crossing the articulation of the knee, when it is between the heads of the gastroc nemii muscles, at the lower edge of the popliteus muscle, it divides into the anterior tibial and the common trunk of the peroneal and posterior tibial arteries. The FEMORAL artery, soon after emerging from Poupart’s ligament, sends off very small branches to the inguinal glands, and other contiguous parts. It also sends off - the External Pudics, Which are two or three small arteries that are generally spent upon the Scrotum in males and the Labia Pudendi in females. About two inches below Poupart’s ligament, the great branch which has been called the muscular artery of the thigh, leaves it. This vessel is commonly denominated ARTERIA PROFUNDA. It arises from the back part of the trunk of the femoral, and passes downwards and backwards, in a way that has been compared to the separation of the internal iliac from the external. Very soon after its origin, it sends off two branches, which proceed, one on the internal, and the other on the external side of the thigh, and are called the circumflexa interna and externa. It then passes down- wards behind the trunk of the femoral, and sometimes Vol. II. 2 N 282 Branches of the Profunda and the Femoral. very near it, on the adductor muscles, and finally divides into branches, which are called the Perforating. The External Circumflex Sometimes arises from the femoral, but most commonly is a branch of the profunda, as above stated. It passes under the rectus and tensor vaginae femoris towards the great trochanter, and generally divides into two branches, one of which continues in the transverse direction, and sends branches to the upper and back part of the thigh, and the parts contiguous to the joint; while the other de- scends in the course of the rectus femoris muscle, and some of its ramifications extend near to the outside of the knee. The Internal Circumflex Is often smaller than the other. It generally passes be- tween the psoas and the pectineus muscles, and continues round the thigh towards the lesser trochanter. Its ramifi- cations are expended on the upper portions of the adduc- tor muscles and the muscular parts contiguous to the lesser trochanter. It also sends branches to the articulation. The Perforating Arteries Are two or three ramifications of the profunda, which pass through the adductor muscles, and are expended upon the flexor muscles on the back of the thigh. Some of the terminating branches of the profunda itself are also called perforating arteries. The next branch of importance which is sent off" by the FEMORAL artery, leaves it before it enters the aperture in the tendon of the adductors, and is called Branches about the Ham. 283 The Anastomotic Artery. This vessel soon inclines downwards. Its ramifications extend into the vastus interims muscle; some of them follow the tendon of the adductors, and ramify about the internal condyle. Several small branches go off from the great artery soon after it passes through the tendon of the adductors, which are distributed to the contiguous muscles. Some of them are also called Perforating Arteries. Among them is the principal medullary artery of the os femoris. In the ham, the great vessel there called POPLITEAL , generally sends off several small branches. Two of them go off on the inside, one above and the other below the knee; and two on the outside in the same manner. They are named, from their situation, The Superior and Infe- rior Internal, and The Superior and Inferior External Articulary Arteries. The Superior Internal artery perforates the tendon of the adductors above the internal condyle, and ramifies minutely on the inner side of the joint. The Superior External artery passes through the lower portion of the biceps above the external condyle, and ra- mifies minutely on the outer side of the joint. Its superior ramifications anastomose with those of the descending branch of the external circumflex, while its inferior rami- fications communicate with those of the corresponding artery below. 284 Arteries of the Leg. The two inferior arteries originate nearly opposite to the middle of the joint, and pass downwards. The Inferior Internal artery passes under the internal head of the gastroc nemius muscle, on the posterior and internal side of the head of the tibia. Its ramifications communicate with those of the corresponding artery above and of the tibialis antica. Below they also extend to the interior of the joint. The Inferior External artery passes under the external head of the gastroc nemius and the plantaris muscle, and continues under the external lateral, and the capsular liga- ment. It is distributed on the external and inferior part of the articulation, and sends also some branches to the interior of the joint. There is frequently an azygous vessel, called the Middle Articular artery, which arises from the back of the popli- teal, and is distributed to the posterior parts of the arti- culation. The POPLITEAL artery, after this, sends off a few small branches to the heads of the muscles of the leg, and among them one of considerable length, to each of the heads of the gastroc nemii. At the under edge of the popiiteus muscle, it sends off horizontally a large branch which passes directly forward between the tibia and fibula, above the commencement of the interosseous ligament. After this it continues to descend, nearly in the same di- rection, under the soleus muscle, behind the tibia; but before it has proceeded further than twelve or fifteen lines, it sends off a branch which forms an acute angle with it, and approaches near the fibula, along which it descends. The branch sent off anteriorly, is called the anterior tisial artery. The main trunk, which continues downwards, is called the posterior tibial artery; 285 Anterior Artery of the Leg. And the branch which descends near the fibula is called the Peroneal or Fibular artery. The anterior tibi al Artery, After its arrival on the anterior part of the leg, passes down close to the interosseous ligament, with the tibialis anticus muscle on the inside, and the extensor communis on the outside, in the first part of its course; and after- wards, with the extensor pollicis pedis on the outside of it. It gradually inclines internally as it descends, so that a little above the ankle it is upon the front part of the tibia. It proceeds thence with the tendons of the extensor digitorum pedis, under the annular ligament, to the upper surface of the foot, on which it continues to the interstice of the first and second metatarsal bones, where it descends to anastomose in the way presently to be mentioned. In this course it sends off, soon after it has arrived at its anterior situation, a recurrent branch , which is distri- buted to the heads of the muscles and the ligaments of the articulation, and which anastomoses with the branches of the inferior articular arteries. It also sends off, on each side, many arterial twigs to the contiguous muscles, and very frequently one branch of considerable size, which passes down near the fibula. When it has arrived near the end of the tibia, it sends a branch on each side, called the Internal and External Malleolar. On the top of the foot, among several smaller arteries, it sends off a branch under the extensor brevis digitorum pedis, which passes outwards and forwards, and supplies the muscles, &c., on the upper part of the foot. This vessel is called Arteria Tarsea. There is also another branch, called Metatarsea , which generally arises about the middle of the foot, and passes obliquely out- ward and forward, supplying the contiguous parts. The anterior tibiae artery, having arrived at the 286 Posterior Tibial and Peroneal Arteries. space between the metatarsal bones of the first and second toes, bends down to the sole of the foot, but previously sends off a branch which passes near the external edge of the metatarsal bone of the great toe, and divides into two branches, one of which goes to the outside of the great toe, and the other to the opposite side of the toe next to it. The posterior tibial Artery , After sending off the anterior tibial, parts with the Pero- neal or Fibular, as has been already stated, and then con- tinues on the back of the tibia, behind the internal ankle, to the sole of the foot. The Peroneal or Fibular Artery Is not commonly so large as either of the two other arteries of the leg, nor is it so constant. It passes down very near the internal edge of the fibula. If is in contact, for some distance, with the tibialis posticus muscle, and is anterior to the soleus and the flexor pollicis longus; it sends branches to the contiguous muscles. After it has passed along two thirds of the length of the fibula, it frequently, but not always, divides into an anterior and a posterior branch. The anterior peroneal soon perforates the interosseous ligament, and passing down some distance on its anterior surface, continues to the ankle and upper surface of the foot. It gives ramifications to all the contiguous parts in its progress, and anastomoses with some of the small ra- mifications of the tibialis antica. The posterior peroneal branch is the continuation of the main trunk. It passes behind the external malleolus, and ramifies upon the external side of the foot. The posterior tibial artery passes down, inclining 287 Arteries of the Foot. rather obliquely inwards, between the gastroc nemius internus, which is posterior to it, and the tibialis posticus and flexor digitorum, which are anterior to it. Upon the leg it gives off many small branches, one of which, termed the Arteria Nutritia Tibia, comes off high up,* and, after ramifying as it descends, sends a branch to the medullary foramen of the tibia. At the lower part of the leg the posterior tibial is situated rather superficially 'between the tendo Achillis and the tibia. It proceeds thence behind the internal ankle in a deep situation, covered by an annular ligament, and passes between the abductor muscle of the great toe and the bones of the tarsus. It then divides into two branches — the internal and the external plantar arteries. The Internal Plantar Artery Is commonly much smaller than the other ramification. It passes in the direction of the internal edge of the foot, but at some distance from it, and often lies between the aponeurosis plantaris and the abductor pollicis. It fre- quently terminates by anastomosing with one of the arte- ries of the great toe, and in its course sends off several branches to the contiguous parts on each side of it. The External Plantar Artery Is the continuation of the main trunk. It proceeds out- wards and forwards between the short flexor of the toes and the flexor accessorius; and continues afterwards be- tween the first of these muscles and the abductor of the little toe. At the metatarsal bone of the little toe it begins to curve, and continues its curvature across the other metatarsal bones to the interstice between the great toe * This artery sometimes comes off from the popliteal. 288 Arteries of the Foot. and the one next to it, passing between the tendons of the long extensor and the metatarsal bones. At the interstice above mentioned, it anastomoses with the tibialis antica. The curvature, thus formed, is called the Arcus Plantaris. In this course, the External Plantar sends off several branches to the heel and the parts of the foot, especially on the external side; the deep seated parts of the foot be- ing supplied from the curve. Digital branches go off from the curve, as they do in the hand, from the curve of the ulnar. There is first a small branch to the outside of the little toe; and then three regular branches, which pass to the junction of the roots of the four small toes, and divide, like the digital arteries of the hand, so as to send a branch to the side of each toe. These digital arteries pass between the muscle called Transversalis Pedis and the metatarsal bones. Near the heads of these bones, each of them generally sends off two arteries that pass upwards between the interossei muscles and the bones, and anastomose with the ramifica- tions from the top of the foot. 1 he External Plantar , soon after sending off the third digital artery, anastomoses with the anterior tibial, and then continues to the junction of the root of the great toe with the one next to it, when it divides into two branches, which go to the opposite sides of those toes. In its course it also sends a branch to the internal side of the great toe. CHAPTER III. OF THE PARTICULAR DISTRIBUTION OF THE VEINS. ANATOMISTS of great respectability have very dif- ferent sentiments lespecting the best method of describing the veins. Some of them, in order to follow the course of the circulation, commence with the small veins, and pro- ceed to the large trunks which are formed by their union. Others begin with the great veins that empty into the heart, and proceed from them to the small ramifications of the venous system, in a direction the reverse of the circulation. As the last method is the easiest for the student of anatomy, it will be adopted here; but it must always be kept in mind, that the blood flows from the small veins into the larger, and not from the latter into the former, as the mode of description seems to imply. The great trunk of the venous system differs consi- derably from that of the arterial with respect to its con- nexion with the heart; for it communicates with that organ in such a manner that, when viewed from before, it ap- pears like two vessels; one opening into the upper, and the other into the lower part of the right auricle. When viewed from behind, it appears like a continued tube, three fourths of which are deficient anteriorly; and to the margin of this deficiency the right sinus or pouch of the heart is connected. In some preparations of the heart, where all the great vessels connected with it are much distended by the in- jection, and the pulmonary vessels are injected first; the right auricle is so much pressed upon from behind, by Vol. II. 2 0 290 V sins of the Heart. the vessels which go to the right lung, that the direction of the superior and inferior portions of the vena cava, which thus communicate with it, is altered. Each of them is turned obliquely forwards, so that it forms an angle with the other. This occasions them to appear more like distinct vessels than they otherwise would do. The above mentioned portions of the great veins are denominated the Superior or Descending , and the Inferior or Ascending Vena Cava; as if they were perfectly distinct and unconnected with each other. The coronary Veins , Which are exclusively appropriated to the heart, may be considered here, as they are not included in the general arrangement of the veins. The great vein of the heart begins at the lower part of the right auricle, very near to the septum, which divides the two auricles. It soon proceeds to the left, in a circular direction, surrounded with adipose matter, in the deep groove which exists between the left auricle and the left ventricle. It continues between 1:116 auricle and ven- tricle, until it is immediately over the septum, which divides the two ventricles. Here its direction changes, and it proceeds to the apex of the heart, where its small ramifications anastomose with others soon to be described. In its course round the basis of the left ventricle, it sends off several branches, one of which is considerable, that pro- ceed from the basis towards the apex of the heart, rami- fying on the surface of the left ventricle. A second vein, much less than the first, appears to pro- ceed from the great vessel at its commencement,* and continues on the lower flat surface of the heart, between the two ventricles, to the apex, accompanied by a branch * It often opens into the auricle by a separate orifice. Superior Vena Cava and its Great Branches. 291 of the right coronary artery. This has been called the Middle vein of the heart. In addition to these there are several veins. which begin at the right auricle, and extend on the surface of the right ventricle towards the apex of the heart. These have been called the Anterior Veins. SECTION I. Of the SUPERIOR or DESCENDING VENA CAVA, and the Veins which communicate with it. THIS great vessel proceeds upwards from the superior and posterior part of the right sinus or pouch of the heart;* and a portion of it is so involved by the pericardium, that it seems to be included in that sac, as the heart is in this situation. It is somewhat anterior as W'ell as to the right of the aorta. It continues above the pericardium, adhering to the right lamina of the mediastinum, and rather inclining forward. When it is as high as the lower margin of the upper rib, it sends off a very large branch, which conveys the venous blood of the left arm and the left side of the head and neck. This large vein, which is very important, both on account of its size and its situation, proceeds in a transverse direction within the sternum, almost in contact with and but little below the upper and internal margin of that bone. Immediately behind or within the origin of the left sterno-mastoid muscle, it divides into the left sub- clavian, which preserves a transverse course, and the left internal jugular, which proceeds to the cavity of the cranium by the foramen lacerum. *See the description of the heart, in page 50 , of this volume. 292 Vena Azygos. After sending off this transverse branch to the left, the great vein continues upwards and behind the right sterno- mastoid muscle, and there sends off, nearly at right angles, the right subclavian vein. After it has parted with this vein, it takes the name of Internal Jugular , and continues to the right foramen lacerum, in the basis of the cranium. —The superior vena cava is, therefore, principally formed by the union of the subclavians and internal jugulars from each side of the body. Immediately after the superior cava rises above the pericardium, before it divides as above stated, it sends off, from its posterior part, a large vein which is single, and therefore called VENA AZYGOS. This vessel projects backward above the right pulmo- nary artery and right branchof the trachea, and then curves downwards behind them. It proceeds down the spine to the right of the aorta and at a small distance from it, into the abdomen, between the crura of the diaphragm, and sometimes between some of the portions of that muscle, which are attached to the dorsal vertebras. In the abdomen it often anastomoses either with the lumbar veins or the vena cava. The azygos frequently sends off several small veins from its curvature to the contiguous parts, and also the right Bronchial Vein , which passes along the ramifications of the trachea into the substance of the lungs.* In its course downwards it gives off branches to the oesophagus, some of which are considerable. The Inferior Intercostal Veins originate directly or in- directly from the azygos. In seme cases there is no Su- perior Intercostal on the right side; and then the two or This bronchial vein sometimes arises from the superior cava. 293 Inferior Intercostal Veins . three uppermost of the right intercostals are also derived from the azygos; and often originate from it by a common trunk, which soon divides. Most commonly the ten inferior intercostals on the right side proceed directly from the azygos, and accom- pany the intercostal arteries. Their posterior branches pass into the vertebral cavity, and communicate with the veins which are there. About the sixth or seventh rib, the vena azygos fre- quently sends off a branch to the left which descends on the left side of the vertebrae, and sends off those Lejt in- tercostal veins which are below its origin. It passes through the diaphragm with the aorta, or to the left of it, and anastomoses either with the azygos itself, or in a way which is analogous to the anastomosis of that vessel. The vena azygos may be regarded as the great trunk of the veins of the parietes of the thorax, which are thus collected, because they could not with convenience pass singly to the vena cava, as the arteries do to the aorta. Soon after sending off the vena azygos, the Superior Cava sends off the great transverse branch above mention- ed. From this it continues upwards but a short distance, when it divides, behind the right sterno mastoid muscle, into the right subclavian and right internal jugular. The branches of the superior cava, which thus inter- vene between the great trunk and the subdivisions behind the sterno- mastoid muscles, are often called the Subclavian Feins; but they do not appear to be accurately named. For, 1st, they are not situated under the clavicle, and, 2dly, they are the common trunks of the subclavians and internal jugulars united. There is a difference in the places where some of the smaller veins originate on each side. The internal mam- mary and the inferior thyroid, on the right side, arise from the superior cava, or from the subclavian at its origin. On the left side they arise from the subclavian. 294 Superior Intercostal Veins. The superior intercostal Veins Are somewhat different on the two sides. That on the right is often the smallest and the least extensive. It com- monly originates from the posterior and inferior part of the subclavian opposite to the origin of the vertebral, and is generally distributed. to the first and second intercostal spaces, but rarely to the third. The Left Intercostal frequently originates near the left internal mammary, and sometimes in common with it. It descends behind the aorta, on the left of the spine, and commonly sends off the six upper intercostal veins, of which the two or three superior pass upwards from a part of the vein which is opposite to the third dorsal vertebra. Its extent is very different in different subjects. In some instances it passes so low as to supply the seventh or eighth intercostal space. This vein also gives off the Left Bronchial Vein , which sends branches to the oesophagus and bronchial glands. The vertebral Veins Arise from the subclavians, but sometimes they proceed differently in different subjects: the right passing behind, and the left before, the subclavian artery of its respective side. Each of them, however, becomes contiguous to its corresponding artery. When it has arrived at the place in the transverse processes, where the artery enters the ver- tebral canal, it sends off an external branch, which passes up, before and nearly in contact with, those processes, and gives ramifications to the contiguous muscles, and also to the cavity of the spine. These last mentioned ramifications enter by the lateral apertures between the transverse processes, and anastomose with the veins and sinuses of the cavity. The branch often finally terminates Vertebral Veins . 295 in the lateral sinus of the dura mater, by passing through the foramen near the mastoid process of the temporal bone. The Main Trunk of the vertebral vein generally sends off another external branch to the muscles near the basis of the neck, and afterwards enters the canal with the vertebral artery. While in this canal, it generally sends off two branches through each of the lateral apertures be- tween the vertebras. One of these branches passes back- wards to the muscles of the neck; and the other proceeds into the great spinal cavity, and communicates with the venous sinuses. When it has arrived at the atlas, the vertebral vein sends branches to the contiguous muscles of the neck. It also frequently sends a branch through the posterior con- dyloid foramen of the occipital bone to the lateral sinus. It is evident, from these circumstances, that the verte- bral vein carries a portion of blood from the sinuses of the brain and of the spinal marrow, as well as from the muscles of the neck, into the subclavian veins. The veins of the head are frequently very different in different subjects. The INTERNAL JUGULAR , , Already mentioned, is often almost exclusively appro- priated to the cavity of the cranium: and all the exterior veins of the head are ramifications of one or more smaller vessels, which pass up superficially on the neck, and are denominated External Jugulars. In some instances almost all the exterior veins of the head are united to the internal jugular at the upper part of the neck, and it of course conveys the blood of the exterior as well as of the interior parts of the head. Frequently these veins are divided be- tween the internal and external jugulars, but they are divided very differently in different subjects. The Internal Jugular , however, almost always passes 296 The Internal Jugular. in the same direction from the inside of the origin of the sterno-mastoid muscle to the posterior foramen lacerum of the cranium. It is deeply seated on the external side of the common carotid artery, and under the sterno-mastoid muscle. Between the upper margin of the thyroid car- tilage and the angle of the lower jaw, it often sends off branches which are very different in different subjects, but commonly pass to the anterior parts of the neck and face: above these it generally sends another to commu- nicate with the external jugular. One of the branches which often go off from the internal jugular is that which corresponds with the superior thyroid or laryngeal artery. This vein, which has sometimes been called the Gut- tural, sends many ramifications to the thyroid gland. The Ranular veins, which are so conspicuous under the tongue, are also derived from it; and it likewise sends branches to the larynx and pharynx. Before the internal jugular enters the foramen lacerum, it suffers a partial dilatation, which is generally larger on one side than the other.* This dilatation occupies the fossa at the foramen lacerum. After passing through the aforesaid foramen, the internal jugular terminates in the lateral sinuses of the dura mater. f These and the other sinuses within the cavity of the cranium are important portions of the venous system, which are interposed be- tween the smaller branches spread upon the pia mater * When the veins of the neck are injected it very often appears that a considerable portion of the internal jugular is much larger on one side than the other, as if it were affected with varicose disten- tion. It also often appears that the general arrangement of the exterior vein is different on the two sides of the head and neck. f It is asserted that the internal coat, or lining membrane of the internal jugulars, is continued into the lateral sinuses, and extends throughout all the sinuses of the dura mater; so that the blood, during its passage through the sinuses, does not come in contact with any membrane different from that of the veins. 297 The External Jugular. and the great trunks of the neck. They are described in the account of the brain, (Vol. I. p. 308). Into these sinuses the very numerous veins of the pia mater open, proceeding to the sinuses* in a direction the reverse of that in which the blood flows in those channels. These veins are divided very minutely on the pia mater before they enter the substance of the brain. Into one of these sinuses, denominated the Cavernous , the ophthalmic vein discharges its contents. This vein proceeds from the anterior part of the sinus into the orbit of the eye through the sphenoid fissure.* Its ramifications correspond generally with those of the ophthalmic arteryf and some of them pass out of the orbit to anastomose with the branches of the facial vein. The superficial veins of the neck are variously arranged in different persons. There is often one considerable vein, The EXTERNAL JUGULAR , , Which is sent off by the subclavian, very near its union with the internal jugular; but sometimes it goes off from that vein much nearer the shoulder. There are sometimes two external jugulars, an anterior and a posterior, nearly of equal size. More frequently one of them is much smaller than the other. In a majority of cases, the princi- pal external jugular goes off" near the junction of the internal jugular and subclavian, as above stated, and proceeds up- wards towards the angle of the lower jaw, passing between the platysma myoides and the sterno- mastoid muscle. It often sends off, at the basis of the neck, one or more branches to the contiguous muscles, and then proceeds upwards. Near the angle of the jaw, it often communi- * See the account of this fissure in Vol. I. p. 53. t The Vasa Vorticosa of the choroides are one of the exceptions to this. See Vol. I. p. 342. Vol. II. 2 P 298 General Account of the Great Vein of the Arm « cates with the internal jugular: it then continues upwards, covered with the parotid gland, near the temporal artery, and finally divides into superficial and deep-seated tem- poral branches. The External Jugular, near the angle of the jaw, often sends olf the facial vein, which crosses the basis of the lower jaw, near the facial artery, and distributes branches to the side of the face and to the forehead. It also very often sends off, near this place, the internal maxillary vein, which generally ramifies in such a manner that its branches correspond with those of the internal maxillary artery. Veins which correspond to some of the other branches of the external carotid artery, the lingual, occi- pital, &c., are often sent off near this place by the external jugular. They take the names of the arteries to which they correspond, and commonly accompany them. The SUBCLAVIAN Vein , Although it originates differently on the two sides of the neck, is situated alike on each of them. After parting with the internal jugular, it proceeds over the first rib, under the clavicle, and does not pass between the scaleni muscles, as is the case with the arteries, but before the anterior muscle. It soon joins the great artery of the arm, and proceeds before or below it to the axilla. In this situation it gives off branches to the contiguous parts, which correspond with those given off by the artery. In this course it also often gives off a large branch, called the CEPHALIC, Which soon becomes superficial, and proceeds down- wards between the margins of the deltoid and pectoral muscles: it continues superficial on the external side of the biceps muscle, sending off many subcutaneous General Account of the Great Vein of the Arm. 299 branches. Near the external condyle of the os humeri, it generally sends off a branch towards the middle of the an- terior part of the fore arm, which is called the Median Cephalic , and also some other superficial branches. It then continues over the radius, and inclining to the back of the fore arm, until it arrives at the back of the hand, where it divides into branches, some of which go to the thumb. In the axilla, the great vein, there called The AXILLARY Vein Generally divides into two or three branches. One, which is commonly the largest, and appears like the continuation of the main trunk, is called The basilic Vein . * This vessel passes down, deeply seated, to the bend of the elbow. It becomes superficial near the internal condyle, and divides into several branches. One of these generally proceeds to join the median branch of the cephalic, and from the union of the two branches is formed the median vein, which passes down near the middle of the anterior part of the fore arm. This vein generally sends off a branch which proceeds internally, and anastomoses with the deep- seated veins of the fore-arm. There are frequently two other branches of the basi- lic vein. One, which is small, passes down on the ulnar side of the anterior part of the fore-arm, but does not ex- tend to the wrist. The other passes down on the ulna, and gradually proceeds to the back of the hand, when it di- vides into several branches, one of which is generally ap- propriated to the little finger. The AXILLARY vein, after the basilic leaves it, sometimes divides into two branches, and sometimes con- 300 Situation of the Inferior Vena Cava . tinues undivided. In either case it accompanies the hu- meral artery, and takes the name of HUMERAL Vein or Veins. It sends oft' branches which correspond to those of the artery, and continues to the bend of the elbow: here it is so divided, that two of its ramifications accom- pany each of the three arteries of the fore-arm. These ramifications sometimes communicate with each other by anastomosing branches near the elbow, and they com- municate also with the superficial veins. The superficial veins of the arm are so different in different subjects, that a general description will rarely apply ac- curately to an individual case. It may, however, be ob- served, that a Cephalic vein will generally be found, which very frequently arises from the subclavian instead of the axillary, and commonly continues to the hand on the ra- dial side of the arm. The superficial veins, on the ulnar side of the fore-arm, very frequently are branches of a large vein which accompanies the humeral artery to the elbow, viz., the basilic; but the median vein, formed by branches of the cephalic and basilic veins, is very often not to be found. SECTION II. Of the INFERIOR VENA CAVA, and the Veins xvhich are connected with it. THIS great vessel exceeds the Superior Cava in di- ameter. It proceeds from the lower part of the right auricle, and verv soon perforates the diaphragm, at a small distance in front of the spine, and rather to the right of the center. As the pericardium adheres to the diaphragm at this place, the vessel appear i to leave it abruptly. Immediately after leaving the diaphragm, it proceeds along a groove in the posterior edge of the liver, formed by the great lobe and 301 Situation of the Inferior Vena Cava. the lo.bulus Spigelii.* After leaving the liver, it continues downwards, inclining backward and to the left, and is soon in contact with the aorta, which is on the left of it. It ac- companies the aorta to its great bifurcation, and divides in the same manner. It sends olf, during this course, branches to the Diaphragm, Liver, Right Renal Gland, the Kidneys, and the Testicles; and also the Lumbar and Middle Sacral veins. The Inferior Phrenic V eins Are thus denominated to distinguish them from other veins, which are derived from the internal mammary, &c. They generally accompany the phrenic arteries, and are distributed in the same manner. The HEPATIC Veins Pass off from the vena cava, nearly at right angles, into the substance of the liver, while it is in the groove of that viscus, and before it has proceeded more than eight or ten lines from the heart. They arise from the anterior part of the vena cava, and are generally three in number. Sometimes there are two only, but then one of them divides immediately after it enters the substance of the gland. The distribution of these vessels in the liver has been detailed in the account of that organ, and, therefore, need not be stated here; but the veins which unite to form the vena portarum, and the trunk of that great vein also, be- fore it is connected with the liver, may be regarded as a portion of the regular venous system, and ought now to be considered. * Sometimes it is completely surrounded by the liver. 302 Superior Mesenteric Vein • The VENA PORT ARUM Passes downwards from die great sinus of the liver behind the pancreas, and inclining to the left. In this course it sends branches to die gall bladder, the stomach and pylo- rus, and the duodenum. At the upper and posterior edge of the pancreas, it sends off a very large branch to the spleen, which often passes, with slight meanders, along a groove in the pancreas. The SPLENIC Vein Often ^ends off the inferior mesenteric vein, which proceeds downwards between the aorta and the left por- tion of the colon. It also sends off some of the coronary veins and the left gastro epiploic vein to the stomach; many small branches to the pancreas; and, finally, either from the main trunk or its branches before they enter the spleen, the venae breves, which pass to the great extremity of the stomach. Before it enters the spleen, it forms several ramifications, which accompany the branches of the splenic artery. After sending off the splenic, the Vena Portarum takes the name of The SUPERIOR MESENTERIC Vein; f Which is larger than the splenic, and passes from behind the pancreas , before the transverse portion of the duodenum , into the mesentery; where it accompanies the superior mesenteric artery. It is evident that the above described portion of the vena portarum simply performs the functions of a great vein; but when it takes on the arrangements for entering the liver, it no longer acts like a vein, but an artery. 303 Emulgent Veins . The lower portion of the trunk of this vein and its ramifications is denominated Vena Porta Ventralis. The part which ramifies in the liver, Vena Porta Hepatica. The Capsular Veins Are small vessels, one on each side. That on the right passes from the vena cava to the right glandula renalis. That on the left arises from the left emulgent vein. The EMULGENT, or RENAL, Veins Are very large vessels; and, like the arteries, go off nearly at right angles, one to each kidney. The right emulgent vein is not so long as the left, and it is rather anterior to its corresponding artery. The left emulgent, in its course to the kidney, crosses the aorta, and is anterior to it. These veins pass to the sinus of each kidney, and ramify before they enter it. The ramifications follow those of the arteries. The Spermatic Veins Arise one on each side: the right from the vena cava, and the left from the emulgent vein. They proceed down- wards behind the peritoneum, and on the psoas muscle generally divide into many branches, which communicate with each other as they progress downwards, and form a plexus denominated Corpus Pampiniforme. These branches proceed in the spermatic cord to the back of the testis. The principal part enters the body of that gland; but some of the branches go to the epididymis. In females the spermatic vein, like the artery, passes to the ovary, the uterus and its appendages, See. 304 Internal Iliac and its Ramifications. The Lumbar V eins Correspond to the arteries of the same name. They arise from the posterior and lateral parts of the inferior cava, and those on the left side pass under the aorta. The Middle Sacral V ein Resembles the artery of the same name in its origin and distribution. The INFERIOR VENA CAVA accompanies the aorta to the space between the fourth and fifth lumbar vertebras, and there it also divides into the two PRIMITIVE ILIAC VEINS. The left vein crosses behind the artery of the right side, and rather behind the left primitive iliac artery, which it accompanies until they are opposite to the junction of the sacrum and ilium, when it divides again, like the artery, into the internal and external iliac veins. The INTERNAL ILIAC or HYPOGASTRIC Vein Descends into the pelvis behind the artery, which it ac- companies. Its ramifications correspond in general with those of the artery, and, therefore, need not be particu- larly described. The VEIfiE VESICALES Have such peculiarities that their ramifications require particular attention. They arise from the hypogastric, very near the origin of the obturator, and are large as well as numerous. They are somewhat different in the two sexes. Ia men Ramifications of the External Iliac. 305 they form a remarkable plexus on the lateral and inferior portions of the bladder, and on the vesiculas seminules. This plexus extends more or less to the prostate: from it a number of veins proceed to the symphysis of the os pubis, which communicate in their course with the pudic vein. From thence arises the great vein of the penis, which proceeds in the groove between the corpora cavernosa, and terminates in the glans penis. This vein often divides, near the root of the penis, into two: one of which is in the groove, and the other more superficial.* In females, the venae vesicales form a considerable plexus on each side of the bladder and vagina. Many veins pass from these to the upper portions of the bladder and the contiguous parts, and form plexuses. The clitoris has a dorsal vein like the penis, and it originates in a manner analogous to the dorsal vein of the male. The EXTERXAL ILIAC Fein. The great trunk of the veins of the lower extremity pro- ceeds on the inside of the artery, under the crural arch or Poupart’s ligament. Before it passes from under the arch, it sends off two branches which answer to the circumflex artery of the ilium and to the epigastric artery. The Circumflex Fein Arises from the external side of the iliac vein, and passes towards the anterior end of the spine of the ilium. It di- vides into branches which accompany those of the artery of the same name. * The pudic veins accompany the arteries of that name. They com- municate with the plexus, as above mentioned, and continue into this" penis. Vol. II. 2 Q 306 Veins of the Leg. The Epigastric Fein Arises from the external iliac, and accompanies the epk gastric artery. — After passing a small distance inward and downward, it turns up on the inside of the abdominal muscles. In the first part of its course it sends off some small branches to the spermatic cord. After passing beyond Poupart’s ligament, the name of the great vessel is changed from external iliac to FEMORAL VEIN. It proceeds downwards at first on the inside of the femo- ral artery, but gradually changes its relative situation, so that in the thigh and in the ham it is behind or on the out- side of that vessel. At a short distance below Poupart’s ligament, after giving off some small branches to the external organs of generation, and to the glands of the groin, it sends off on the internal side of the thigh a very large vein which is called the 1 ' SAPHENA MAJOR. This vein immediately becomes superficial, and passes down on the internal side of the thigh, somewhat ante- riorly; giving off' some small branches to the contiguous parts, soon after it originates; and many superficial veins afterwards. It continues along the inside of the knee and leg to the internal ankle, the anterior part of which it passes over. It then proceeds along the internal part of the upper surface of the foot to the middle, when it curves towards the external edge, and joins the lesser saphena. On the leg and foot it also sends off many branches, which anastomose with each other, and with those of the afore- said vein. Instances of peculiar arrangement of the V eins. 307 The femoral vein, after parting with the saphena, soon sends off the vena profunda, and the circumflexae also, when they do not arise from the profunda. These veins are generally larger than the arteries to which they correspond, and their branches are more numerous; but they observe the same course. The great vein accompanies the artery down the thigh >and through the perforation in the biceps; but it changes its relative position, so that it is placed behind or on the exterior side of the artery at the lower part of the thigh. It is very often behind it in the ham, where, like the artery, it takes the name of POPLITEAL. In the ham it sends off another superficial vein, which seems very analogous to the basilar vein of the arm. This is called The Lesser or External Saphena. It proceeds from the ham over the external head of the gastroc nemius, and down the outside of the leg, sending off many branches in its course. It passes behind the ex- ternal ankle and near the exterior edge of the upper sur- face of the foot, about the middle of which it inclines to- wards the great saphena, and forms with it the anastomosis already mentioned. The popliteal vein, after passing across the articulation, ramifies like the artery, but sends two veins, which ac- company each of the three arteries of the leg. In a few instances some of the larger veins have been found to be arranged in a manner very different from that which is commonly observed. One case of this kind has already been mentioned in the account of the liver, * where the Vena Port arum terminated * See note to p. 135, of this volume. 308 Pulmonary Vessels . in the Vena Cava , below the liver, without entering into it. Another very remarkable instance of peculiar arrange- ment is to be seen in a preparation now in the University of Pennsylvania, in which the Inferior Cava , instead of opening into the lower part of the right auricle, passes behind it, in the tract of the Vena Azygos, and opens into the Superior Cava, in the place where the Vena Azygos usually communicates with that vessel, receiving the In- tercostal Veins in its course. In this preparation, the Hepatic Veins communicate directly with the right auricle, at its lower part; the middle and left hepatic veins forming one trunk before they enter, and the right vein passing in singly. Of the PULMONARY Artery and Veins . Those portions of the pulmonary artery and veins which are distinct from the lungs may be described very briefly. It has been already observed,* that the pulmonary artery arises from the left and most anterior part of the basis of the right ventricle, and proceeds thence obliquely backwards, inclining gradually to the left side for about eighteen or twenty lines, when it divides into two branches, which pass to the two lungs. This course places it under the curve of the aorta: for that great vessel passes over the right branch of the pulmonary artery, and the right side of the main trunk of it, in such a manner that it proceeds downwards between the two branches and behind the angle formed by their bifurcation. From this place of bifurcation a short ligament proceeds to the lower part of the curve of the aorta, which is almost in contact with it. This ligament was originally the canal that formed * See page 59 of this volume. Pulmonary Vessels . 309 the communication between the pulmonary artery and the aorta of the foetus.* Each of the great branches of the pulmonary artery takes a direction backwards, and to its respective side. It soons joins the corresponding branch of the trachea and the two pulmonary veins, being ante- rior to the branch of the trachea, and above the pulmonary veins. It is also invested, in common with them, by that portion of the pleura which forms the mediastinum, and thus enters into the composition of the root of the lungs. The pulmonary veins are four in number — two on each side. In conformity to the mode of description which we have adopted, it may be said that they arise from the sides of the Left Auricle , and proceed nearly in a trans- verse direction, two of them to each lung; where they ac- company the branches of the artery and of the trachea, being invested by the mediastinum in common with these branches. It has been observed, that they differ from veins in general, by preserving a diameter nearly similar to that of the arteries which they accompany. * See page 68. SYSTEM OF ANATOMY. PART X. OF THE NERVES. The nerves are those whitish cords which pass from the brain and spinal marrow to the various parts of the body. A general account of their origin is contained in the description of the basis of the brain and of the spinal marrow,* which may be considered as introductory to the present subject. The nerves, in general, appear to be bundles or fasci- culi of small cords, each of which is composed of a series of fibres that are still smaller. These fibres consist of me- dullary matter, which is derived from the brain and spinal marrow, and is inclosed in a membranous sheath that ap- pears to arise from the pia mater. The smaller the fibre, the more delicate is the membrane which invests it. As the nerves proceed from the brain and spinal mar- row, through the foramina of the cranium and the spine, they are inclosed in a sheath formed by the dura mater; but when they arrive at the exterior extremity of the fo- ramina in those bones, this coat, derived from the dura mater, appears to separate into two laminae. The exterior lamina combines with the periosteum, and the interior *See volume I. page 321. 311 General Structure of the Nerves. continues to invest the nerve, but seems to change im- mediately into cellular substance; so that the exterior coat of the nerves may be regarded as composed of cellular membrane, which is continued from the sheath derived from the dura mater. It has been supposed that the membrane which forms the sheaths for the medullary fibrils, of which the nerves are composed, is of a peculiar nature; but it appears to be derived from the pia mater, investing the brain and the spinal marrow. It is very vascular.* The ramification of a nerve is simply the separation of some fibres from the general fasciculus. The branch com- monly forms an acute angle with the main trunk. The course of these branches, from their origin to their termination, is generally as straight as possible. When the nervous cords are examined in an animal recently dead, there is an appearance of white lines ar- ranged in a transverse or spiral direction. The cause of this appearance is not well understood. In various parts of the body networks are formed by the combination of different nerves, or the branches of nerves. In those instances the branches of one nerve unite with those of another, and form new branches. These new branches again divide, and their ramifications unite with other new ramifications to form other new trunks. These new trunks divide again, and form new combinations in the same way. The trunks last formed proceed to the different parts of * Several authors have written professedly on the structure of the nerves, viz. Monro, in his “ Observations on the Structure and Func- tions of the Nervous System.” — Bichat, “ Anatomie Generale.” — Fontana, “ Treatise on the Poison of the Viper.” — Reil, “ Exercita- - liones Anatomicae.” — Scarpa, “ Annotationes Academicae.” — Pro- chaska, “ De Structura Nervorum.” I regret that it has not been in my power to procure Reil, Pro- chaska, or Scarpa. 312 Plexuses . — Ganglions. the body, as other nerves do which arise immediately from the brain. These combinations are denominated Plexuses. There are several of them in the cavities of the abdomen and thorax, formed by the ramifications of the par vagum and the sympathetic nerves. The four lower cervical and the first dorsal nerve form a very remarkable plexus of this kind, which extends from the side of the neck to the axilla, and forms the nerves of the arm. The lumbar nerves form a similar plexus, although not so complex, from which the crural nerve arises. The anterior nerves of the sacrum also unite for the formation of the great sciatic nerve. It appears to be clearly ascertained, that the great object of this peculiar arrangement is the combination of nervous fibres from many different sources, in each of the nerves, which are distributed to any organ. Thus, the smaller nerves of the arm that are distributed to the dif- ferent parts, are not to be regarded simply as branches of any one of the five nerves which are appropriated to the upper extremity, but as composed of fibres which are derived from each of them. Many of the nerves are enlarged in particular places, so as to form small circumscribed tumours, which are denominated Ganglions. These Ganglions are generally of a reddish colour. By very dextrous management, they can be shown. to consist of a texture of fibres. The larger cords, which compose the nerve, seem suddenly to be resolved into the small fibres, of which they consist. These small fibres, after proceeding separately a greater or lesser distance, accord- ing to the. size of the ganglion, and changing their relative situation, are again combined in cords which recompose the nerve. These fibres appear to be surrounded by a fine cellular substance, which is vascular, moist and soft. It is assert. Structure of Ganglions. 313 ed that, in fat subjects, an oily substance, resembling fat; and in hydropic subjects, a serous fluid has been found in this texture. Ganglions are often connected with but one nerve, which seems to enter at one extremity and go out at the other. But they frequently receive additional branches from other nerves, and send off additional branches to parts different from those to which their principal nerves are directed. When connected with but one nerve, they have been called simple ganglions: when they receive and give off additional branches, they are denominated com- pound ganglions . — It does not appear that there is any im- portant difference in their structure in these cases. The simple ganglions occur in the nerves of the spinal marrow — the posterior fasciculus of the nerves having always formed a ganglion before it is joined by the ante- rior fasciculus. The sympathetic nerve, throughout its whole extent, forms compound ganglions. The use of this particular structure does not appear to be perfectly known. It seems, however, certain, that the different fibres — (of which the nerves forming ganglions are composed) — are blended together and arranged in a manner different from that in which they were arranged before the nerve entered the ganglion. It ought to be observed, that the combination of nervous fibrillae, so as to bring together those fibrils which originally belonged to different cords, seems to have been kept in view throughout the whole arrangement of the ner- vous system. It is not only in the plexus and the ganglion that this appears, but also in some of the larger nerves; for in them, the fibres which form the cords that compose the nerve, instead of running parallel to each other, along the whole extent of the nerve, form a species of plexus in their course; separating from the fibres with which they Vol. II. 2 K 314 Reproduction of Nerves. were originally combined, and uniting with the fibres of other cords; as in other cases of plexus.* There have been doubts respecting the possibility of a reproduction of the substance of the nerves when it has been destroyed; but it appears to have been clearly proved by the experiments of Mr. Haighton, that a reproduction does really take place. f Nine pair of nerves proceed from the brain through the foramina of the cranium. They are called Nerves of the Brain , or Cerebral Nerves. One pair pass off between the cranium and the spine, which are called Sub ■ Occipital . Twenty-nine or thirty pair pass through the foramina of the spine: they are denominated Cervical , Dorsal , Lumbai' and Sacral , from the bones with which they are respec- tively connected. There are seven pair of Cervical nerves, twelve Dorsal, five Lumbar, and five or six Sacral — amounting, with the nerves of the brain, to thirty- nine or forty pair. NERVES OF THE BRAIN. The nerves which go off from the brain and medulla oblongata are named numerically, according to the order in which they occur; beginning with the anterior. They also have other names, which generally are expressive of the functions of the different parts to which they are dis- tributed. Those which go to the nose are anterior to all the others, and are therefore denominated * See Monro’s Observations on the Structure and Functions of the Nervous System. Plate xviii. t See London Philosophical Transactions, for 1795, Part I. Olfactory Nerves. 315 THE FIRST PAIR, OR THE OLFACTORY NERVES. They arise by three delicate white fibres from the under and posterior part of the anterior lobes of the brain, being derived from the Corpora Striata. They proceed forward to the depression on the cribriform plate of the ethmoid bone, on each side of the crista galli. The upper surface occupies a small sulcus formed by the convolutions of the lower surface of the brain, and, therefore, has a lon- gitudinal ridge on it. The lower surface is flat. Their texture is like that of the medullary part of the brain. On each side of the crista galli each of them forms a pulpy enlargement of a brownish colour, which is called the bulb, and has been considered as a ganglion. From this bulb many fine and delicate cords go off, which proceed through the dura mater and the foramina of the cribriform plate to the Schneiderian membrane. — These ramifications of the olfactory nerve seem to receive a coat from the dura mater, as they are much more firm after they have passed through it. They appear to be arranged in two rows as they proceed from the ethmoid bone — one running near to the septum, and the other to the opposite surface of the ethmoid bone.* THE SECOND PAIR, OR THE OPTIC NERVES, Originate from the Thalami Nervorum Opticorum , and appear on the external and lower surface of the brain, on each side of the sella turcica. Each of them seems like a cord of medullary matter, inclosed in a coat derived from the pia mater, and has not the fasciculated appearance of the other nerves. The medullary matter, however, appears to be divided by * See Vol. II. Page 6. 316 Second and Third Pair of Nerves. processes that pass through it, which are derived from the coat of the nerve. They proceed obliquely forward and inward, on each side of the sella turcica, in contact with the brownish cineritious substance, in which the infundibulum and the corpora albicantia of Willis are situated.* Anterior to this substance they come in contact with each other, and again separate, in such a way, that it is an undecided question whether they decussate each other, or whether each forms an angle, and is in contact with the other at the angle. From this place of contact, each nerve proceeds to its respective foramen opticum, where it receives a coat from the dura mater, which extends with it to the eye, as has been described in the account of that organ. THE THIRD PAIR OF NERVES Are sometimes called Motores Oculorum , in consequence of their distribution to several muscles of the eye. They arise at the inside of the crura cerebri, and make their ap- pearance on the basis of the brain, at the anterior part of the pons Varolii. They originate by numerous threads, which soon unite so as to form a cord that passes through the dura mater, on each side of the posterior clinoid process, and continues through the cavernous sinus, and the foramen Iacerum, to the orbit of the eye. Before this nerve enters the orbit it generally divides into two branches, which are situated one above the other. The Uppermost Branch'is spent principally upon the rectus superior muscle of the eye, but sends a twig to the levator palpebras. The Inferior Branch is distributed to two of the recti muscles, viz. the internus and the inferior, and also * See Vol. I. p. 323. 317 Fourth and Fifth Pair of Nerves. to the inferior oblique. It likewise sends a twig to a small ganglion in the orbit, called the Lenticular or Ophthalmic Ganglion * from which proceed the fine nerv- ous fibres that perforate the sclerotica eoat.f THE FOURTH PAIR OF NERVES Are called the Pathetic , in consequence of the expression of the countenance produced by the action of the muscle on which they are spent. They arise from the side of the valve of the brain, below and behind the Tubercula Qua- drigeminal and are so small that they appear like sewing thread. They proceed round the crura of the cerebrum, and appear on the surface between the pons Varolii and the middle lobes of the brain. They proceed along the edge of the tentorium which they perforate, and passing through the upper part of the cavernous sinus, enter the orbit by the foramina lacera. They are exclusively appro- priated to the Superior Oblique or Trochlearis muscle. THE FIFTH PAIR OF NERVES Are called Trigemina , because each nerve divides into three great branches. These nerves arise from the crura of the cerebellum where they unite to the pons Varolii, by distinct fibres, which are connected so as to form a cord or nerve, that i$ larger than any other nerve of the brain. In many subjects this cord seems partially divided into two portions, the anterior of which is much smaller than the posterior, and appears softer at its origin. •This ganglion, which is considered as the smallest in the body, lies on the outside of the optic nerve, near its entrance into the orbit, and is generally surrounded by soft adipose matter t See Volume I. page 342. 4 Ibid. Page 324 318 First Branch of the Fifth Pair. It passes into a short canal formed by the dura mater, near the anterior extremity of the petrous portion of the temporal bone, at a small distance below the edge of the tentorium. It is perfectly loose and free from adhesion to the surface of this canal; but it soon passes out of it under the dura mater, and then adheres to that membrane. After leaving the canal it expands like a fan, but still consists of fine fibres which have some firmness. It is said that there are seventy or eighty of these fibres in the expansion, but they appear to be more numerous. Round the circumference of the expansion is a substance of a brownish colour, into which the fibres enter. This is the Semilunar Ganglion , or the Glangion of Gasser, and from it the three nerves go off. These nerves pass off from the convex side of the Ganglion, and are denominated the Ophthalmic , the Su- perior Maxillary, and the Inferior Maxillary. The Ophthalmic Nerve Passes into the orbit of the eye through the foramen lacerum: it there divides into several branches, which are called, from their distribution, the Frontal or Supra- Orbitar, the Nasal and the Lachrymal. The Frontal or Supra- Orbitar branch proceeds forward in the upper part of the orbit, exterior to the membrane which lines it, and divides into two ramifications. One of these is small, and passes out of the orbit near the pulley of the superior oblique, to be spent upon the orbicularis muscle and the contiguous parts. The other ramification passes through the Supra-Qrbi- tary Foramen, or through the notch, which is in the place of that foramen, and divides into a number of twigs, some of which pass transversely towards the side of the head, and communicate with twigs from the portio dura. Most of the others extend upwards on the head. Some are dis- .319 Second Branch of the Fifth Pair. • tributed to the anterior part of the occipito frontalis mus- cle, and the integuments of the forehead; others are spent upon the upper portion of the scalp. Some of the extreme parts of these ramifications also communicate with the portio dura. The Nasal Branch proceeds obliquely forward towards the inner side of the orbit, and sends a twig in its course to the lenticular ganglion. It also sends off some small twigs, to join the ciliary nerves which go from the gang- lion. On the inside of the orbit a branch leaves it, which proceeds through the Foramen Orbitare Internum Anterius to the cavity of the cranium, and passes a small distance upon the cribriform plate of the ethmoid bone, under the dura mater, to a fissure in the said plate near the crista galli, through which it proceeds into the cavity of the nose. Here it divides into twigs, some of which pass on the septum near its anterior edge, and terminate on the integuments at the end of the nose, while others pass down on the inferior turbinated bone. After parting with the ramification to the nose, the remainder of the nasal branch continues to the internal canthus of the eye, and sends twigs to the lachrymal sac, the caruncula lachrymalis, the eye-lids, and the exterior surface of the upper part of the nose. The Lachrymal Branch proceeds obliquely forward and outwards, towards the lachrymal gland. In its course it sends off a twig which passes through the spheno maxillary fissure, and communicates with a twig of the upper maxilLary nerve, and one or more twigs that pass to foramina in the molar bone. The main branch passes to the lachrymal gland, and some twigs Continue beyond it to the contiguous parts. The Superior Maxillary Nerve. The second branch of the fifth pair is examined with great difficulty^ on account of its peculiar situation. It 320 Second Branch of the Fifth Pair: or proceeds from the semilunar ganglion, and passes through the foramen rotundum of the sphenoid bone into the upper part of the zygomatic fossa. In this situation it sends a twig to the orbit by the spheno maxillary fissure, and a branch, called the Infra Orbitar , which appears like the main nerve, as it preserves a similar direction, to the infra orbitar canal. At the same place it sends downwards two branches which unite together almost immediately after their origin, and, as soon as they have united, enlarge into a ganglion.* This glangion is called the Spheno- Palatine. It is rather of a triangular figure, and lies very near the spheno-palatine foramen. It gives off a posterior branch, which passes through the pterygoid foramen to the cavity of the cranium: some branches which proceed through the spheno-palatine foramen to the nose, and are called the Spheno- Palatine or, Lateral Nasal Nerves: and an inferior branch, that proceeds through the posterior palatine canal, and is called the Palatine Nerve. The small branch, which was first mentioned, as going to the orbit by the spheno maxillary fissure, divides into two ramifications. One of them unites with a twig of the lachrymal branch above mentioned, and passes out of the orbit, through a foramen in the molar bone, to the face; , where it is distributed. The other passes also through a foramen of the molar bone, into the temporal fossa, and, after uniting with twigs from the Inferior Maxillary A r erve, proceeds backwards and perforates the aponeurosis of the temporal muscle, to terminate on the integuments of the temporal region. Before the Infra Orbitar branch enters the canal of that name, it sends off two twigs, called Posterior Dental Nerves , which pass downwards on the tuberosity of the upper maxillary bone, and enter into small canals in that bone, that are situated behind the Antrum Maxillare. * Sometimes a single branch passes downwards instead ol two; but it forms a ganglioo in the same place. 321 Superior Maxillary Nerve. They subdivide into fine twigs that proceed forward to the alveoli of three or four of the last molar teeth; and pene- trate each of the roots by a cavity at its extremity. Twigs also proceed from these nerves to the posterior part of the gums and the buccinator muscle. After the posterior dental nerves have left it, the Infra Orbitar nerve proceeds forwards in the canal of that name; and near the extremity of it, gives off the anterior dental nerve, which accompanies it for some distance, and then proceeds downwards in a canal in the bone anterior to the antrum maxillare. In its course this nerve divides into many fibres, which pass to the roots of the incisor, canine, and small molar teeth, each in its proper canal. These dental branches sometimes pass in the antrum maxillare between the lining membrane and the bones. The Infra Orbitar nerve passes out of the foramen upon the cheek, and divides intb several branches of considera- ble size, which are distributed on the face from the side of the nose to the back of the cheek, and also upon the under eye-lid and the upper lip. The Pterygoid Nerve, or posterior branch, passes backwards, from the ganglion to a canal in the base of the pterygoid process of the Os Sphenoides, and proceeds through it. After leaving this canal, it passes through a substance almost as firm as cartilage, which closes the an- terior foramen lacerum, at the basis of the cranium; and divides into two branches. The smallest of them, called the Vidian Nerve , proceeds with a small artery to the small foramen, or Hiatus Fallopii, on the anterior side of the petrous portion of the temporal bone, and continues, through a small canal, to join the Portio Dura of the seventh pair in the larger canal, called the Aqueduct of Fallopius , at the first turn in that canal.* The other branch * The late Mr. John Hunter believed that this nerve parts from the portio dura at the lower end of the aqueduct, and is the corda tympani. Vol. II. 2 S 322 Superior Maxillary Nerve. of the pterygoid nerve proceeds to the Foramen Caro- ticum, and passes through it, with a twig of the sixth pair, to join the first cervical ganglion of the Intercostal Nerve. The Spheno- Palatine, or Lateral Nasal Nerves, consist of several branches which pass from the spheno-palatine ganglion, through the spheno-palatine foramen, into the nose. Some of them are distributed to that part of the pituitary membrane, which is above the upper meatus, and others to the part which is immediately below it. Some of the branches which thus enter the nose are spread upon the septum: one among them extends upon it, down- wards and forwards, to the anterior part of the palatine process of the upper maxillary bone, where it enters into the foramen incisivum, and terminates in a papilla in the roof the mouth.* The Palatine Branch proceeds, through the canal form- ed by the upper maxillary and palate bones, to the roof of the mouth and the soft palate. Soon after its origin, it sends off a twig which proceeds down a small canal that is behind it. It also sends off, as it proceeds downwards, several twigs to that part of the membrane of the nose which covers the inferior turbinated bone. When it ar- rives at the roof of the mouth, it divides into several branches which run forwards, and are distributed to the membrane which lines the roof of the mouth. Some of its branches pass to the soft palate, the uvula, and the tonsils; small filaments pass into the back part of the upper jaw. *The curious distribution of this nerve appears to have been known to the late John Hunter, and also to Cotunnius; but it is mi- nutely described by Scarpa, and is delineated by Soemmering in his plate of the nose. — See “ Observations on certain parts of the Animal Economy,” by J. Hunter, page 219, — and also Scarpa “ De Organo Olfactus.” in this last are some interesting observations relative to the ducts of Stcno. Third Branch of the Fifth Pair . 323 The Inferior Maxillary Nerve, or the Third Branch of the Fifth Pair , Passes through the foramen ovale into the zygomatic fossa, and divides into two branches , one of which sends ramifications to many of the contiguous muscles, as the Temporal, the Masseter, the Buccinator, the Pterygoid; and also to the anterior part of the ear and the side of the head. The other branch passes between the pterygoid muscles, and divides into two ramifications, one of which proceeds to the tongue, and is called the Lingual ox Gus- tatory, while the other passes into the canal of the lower jaw. The Lingual Nerve proceeds between the pterygoid muscles, and in its course is joined by the chorda tym- pani. It continues forward between the maxillary gland and the lining membrane of the mouth; and passes near the excretory duct of that gland, above the mylo-hyoideus and the sublingual gland, to the under side of the tongue, near the point: it then divides into a number of branches which enter into that body between the genio hyoideus and lingualis muscles. — This nerve has been supposed to be particularly concerned in the function of taste, because many of its branches continue to the upper surface of the tongue, especially near the point. In its course it has a communication with the ninth pair of nerves, and it sends twigs to the membrane of the mouth and gums, and the contiguous parts. After parting with the lingual nerve, the inferior max- illary continues to the upper and posterior orifice of the canal in the lower jaw. Before it enters this canal it sends a branch to the sub-maxillary gland, and to the muscles under the jaw. It then enters the canal, attended by blood- vessels, and proceeds along it to the anterior maxillary foramen, on the side of the chin, through which it passes 324 Sixth and Seventh Pair of Nerves. out. In this course it sends twigs to the sockets of the teeth, and generally supplies all the large and one of tlie small grinders. Before it leaves the jaw it sends a branch forwards, which supplies the Remaining teeth on the side to which it belongs. After passing out, through the ante- rior foramen, it is spent upon the muscles and integuments of the front of the cheek, the chin, and the under lip. THE SIXTH FAIR OF NERVES Are called Motores Externi. They arise from the com- mencement of the medulla oblongata, and proceed for- ward under the pons Varolii. They proceed through the dura mater on the inside of the fifth pair, and appear to pass through the cavernous sinuses, but are inclosed in sheaths of cellular membrane while they are in those sinuses. When in this situation they are near the carotid arteries, and each nerve sends off one or more very fine twigs, which being joined by a twig from the pterygoid branch of the fifth pair, accompany the carotid artery through the carotid canal, and then unite themselves to the upper extremity of the upper cervical ganglion of the intercostal nerve. The sixth pair afterwards pass into the orbit of the eye, each through the foramen lacerum of its respective side, and is spent upon the Rectus Externus or Abductor mus. cle of the eye. THE SEVENTH FAIR OF NERVES Comprises two distinct cords which have very different destinations; and have, therefore, been considered as dif- ferent nerves, by several anatomists. One of these cords is appropriated to the interior of the ear, and is the proper Auditory Nerve. The other is principally spent upon the face, and, therefore, has been called the Facial. They have, however, more frequently been denominated the Seventh Pair , and distinguished from each other, in con- t Composition of the Seventh Pair. — Portio Dura. 325 sequence of a great difference in their texture, by the appellations of Portio Dura and Portio Mollis. These two cords pass off nearly in contact with each other, from the side of the upper part of the Medulla Ob- longata , where it is in contact with the pons Varolii; but the Portio Mollis can be traced to the fourth ventricle, while the Portio Dura is seen to arise from the union of the pons Varolii with the medulla oblongata and the crura Cerebelli. The Portia Dura , at its origin, is on the inside of the Portio Mollis. — Between these cords are one or more small fibres, called Portio Media, which seem to originate very near them, and finally unite with the Portio Dura. Each of the seventh pair of nerves, thus composed, proceeds from its origin, to the Meatus Auditorius In- ternus of the temporal bone; and the Portio Mollis divides into fasciculi, which proceed to the different parts of the organ of hearing, in the manner described in the account of the ear.* The Portia Dura enters an orifice at the upper and anterior part of the end or bottom of the Meatus Audito- rius Internus. This orifice is the commencement of a Canal, which has been called the Aqueduct of Fallopius , and proceeds from the Meatus Auditorius Internus to the external foramen, between the mastoid and stiloid pro- cesses at the basis of the cranium. This canal first curves backwards and outwards, near to the upper surface of the petrous bone, then forms an acute angle, and proceeds (backwards and downwards) to the stilo-mastoid fora- men, passing very near the cavity of the tympanum in its course. The Portio Dura, as it passes into the canal from the meatus internus, seems to receive an investment from the dura mater. It fills up the canal, but does not appear to be * See Volume I, page 380. 326 Chorda Tympani. — Pcs Atiserinus. compressed. Near the angle it is joined by the twig of the vidian nerve, which proceeds from the pterygoid branch of the fifth pair, and enters the petrous bone by the small foramen innominatum on its anterior surface. In its course through the canal it sends oflf some very small twigs to the muscles and appurtenances of the small bones of the ear, and to the mastoid cells; and, when it has arrived almost at the end of the canal, it sends off, in a retrograde direction, a smallbranch which proceeds into the cavity of the tympanum, (entering it by a foramen at the base of the pyramid,) and crosses the upper part of it, near the membrana tympani, between the long pro- cesses of the Malleus and Incus. This twig is the Chorda Tympani: it proceeds from the cavity, by a fissure on the outside of the Eustachian tube, to join the lingual branch of the fifth pair, as has been already mentioned.* The Portio Dura , after passing out of the Foramen Stylo- Mas toideum, is situated behind and within the pa- rotid gland. Here it gives small twigs to the back of the ear and head, and to the digastric and stylo-hvoideus muscles. It perforates the gland after sending filaments to it, and then divides into branches which arc arranged in such a manner that they constitute what has been called the Pes Anserinus. To describe the various branches in this expansion would be more laborious than useful. Some of them are spread upon the temple and the upper part of the side of the head, and unite with the supra-orbitar branches of the ophthalmic nerve. Some pass above and below the eye, and are distributed to the orbicularis muscle, and communicate with nervous twigs that pass through fora- * The lateJohn Hunter believed that the chorda tympani is mere- ly a continuation of the twig of the pterygoid branch which joins the portio dura above. — See Observations on certain parts of the Ani- mal Economy, page 220. Composition of the Eighth Pair of Nerves. 327 mina in the malar bone, &c. Some large branches pass transversely. They cross the masseter muscle, and divide into ramifications which are spent upon the cheek and the side of the nose and lips, and communicate with the small branches of the superior maxillary nerve. A large number of branches pass downwards. Many of them incline forwards, and are spent on the soft parts about the under jaw; while others proceed below the jaw to the superficial muscles and integuments of the upper part of the neck, communicating with the branches of the contiguous nerves.* THE EIGHTH PAIR OF NERVES Are very frequently denominated the Par Fagum, on account of their very extensive distribution. They arise from those portions of the medulla oblon- gata which are denominated the Corpora Olivaria. Each nerve consists of a cord, which is anterior, and called the Glosso- Pharyngeal ; and of a considerable number of small filaments, which arise separately, but unite and form another cord, the proper Par Vagum. Associated with these is a third cord, called the Spinal, or Accessory Nerve of Willis, which originates in the great canal of the spine, and, passing up into the cavity of the cranium, goes out of it with these nerves through the foramen lacerum. The two first mentioned nerves proceed from their origin to the posterior foramen lacerum, and passthrough it with the Internal Jugular vein, — being separated from the vein by a small process of bone. They are also separa- * A most minute and laborious description of the nerves of the face was published by the celebrated Meclde, in the seventh volume of Memoirs ot the Royal Academy of Sciences of Berlin, for the year 1751, accompanied with a plate, exhibiting the side of the head, of three times the natural size. This is republished in the Collection Academique: Partie Etrangere.— Tom. viii. 323 Glosso * Pharyngeal Nerve. — Par Vagum. ted from each other by a small process of the dura mater. In the foramen they are very close to each other; but soon after they have passed through it, they separate and pro- ceed towards their different destinations. The Glosso- Pharyngeal proceeds towards the tongue, between the stylo-pharyngeus and the stylo-glossus mus- cles, following the course of the last mentioned muscle to the posterior part of the tongue. At the commencement of its course it receives a twig from the Portio Dura and one also from the Par Vagum. It soon gives off a branch which passes down on the inside of the common carotid to the lower part of the neck, where it joins some twigs of the intercostal to form the cardiac nerves. Afterwards it sends off several twigs to the muscles of the pharynx and its internal membrane, and also some twigs which unite with others from the upper cervical ganglion of the Sympathetic , and form a network that lies over the anterior branches of the external carotid. The Glosso- Pharyngeal finally enters the tongue, at the termination of the hyo- glossus muscle; and after sending branches to the lingu- alis, and the various muscles inserted into the tongue, terminates in small ramifications that are spent upon the sides and middle of the root of the tongue, and upon the large papillae. THE PAR VAGUM Are slightly enlarged after passing through the foramen lacerum. As they descend, they adhere to the superior ganglion of the intercostal, and also to the ninth pair. They proceed behind and on the outside of the carotid, and are contained in the same sheath of cellular membrane which incloses that artery and the internal jugular vein. Each of these nerves, soon after it leaves the cranium, gives a twig to the glosso-pharyngeal; that soon after it sends oft' a branch called the Pharyngeal , which unites Superior Laryngeal Branch of the Par Vagum. 329 to one from the accessory nerve, and to one or more from the glosso-pharyngeal, and proceeds to the middle constrictor of the pharynx, when it expands into ramifica- tions that form a plexus from which proceed a number of small twigs that go to the larynx, and some that pass down on the common carotid artery. It then sends off, downward and forward, the Superior Laryngeal nerve, which continues in that direction behind the carotid artery, and divides into an external and inter- nal branch. The Internal Branch , which is the largest, proceeds between the os hyoides and the thyroid cartilage; and divides into numerous ramifications which are distributed to the arytenoid muscles and to the membrane which lines the larynx and covers the epiglottis. It is said, that fine twigs can be traced into the foramina, which are to be seen in the cartilage of the epiglottis; — some ramifications can be traced to the pharynx; — others communicate with the branches of the recurrent nerve. The External Branch sends twigs to the pharynx, to the lower and inner part cf the larynx, and to the thyroid gland. In its course downwards, the great nerve sometimes sends off a twig, which unites with one from the ninth pair that passes to the sterno-hyoidei and sterno-thyroidei muscles. It uniformly sends off one or more twigs, which pass into the thorax and combine with small branches from the sympathetic or intercostal nerve, to form the Cardiac Plexus, which sends nerves to the heart. After entering the thorax, the right trunk of the Par Vagum passes before the subclavian artery; and the left trunk before the arch of the aorta; and immediately after passing these arteries, each of the nerves divides into an anterior and posterior branch. — The anterior is the con- tinuation of the Par Vagum; the posterior is a nerve of Vol. II. 2 T 330 Recurrent Branch of the Par Vagum . the Larynx; which, form its retrograde course, is called the Recurrent Nerve. On the leh side the Recurrent Nerve winds backwards round the aorta, and on the right side round the subclavian artery, and proceeds upwards, deeply seated, on the side of the trachea, to the Larynx. Soon after its origin it sends filaments to a ganglion of the sympathetic, to the cardiac plexus, and to a pulmonary plexus soon to be mentioned. In its course upwards it sends twigs to the trachea and the oesophagus. It proceeds behind the thyroid gland, and sends twigs to that organ. At the lower part of the larynx it sends of a branch which communicates with branches of the superior laryngeal nerve. It also divides into branches which are spread upon the posterior crico- arytenoid, and the arytenoid muscles; and also upon the lateral crico -arytenoid and the thyro-arytenoid muscles, as well as upon the membrane which lines the back part of the larynx and the contiguous surface of the pharynx. There is a difference in the arrangement of the recur- rents on the different sides, in consequence of one winding round the aorta, while the other winds round the subcla- vian artery. After sending off the recurrents, each trunk of the Par Vaguin proceeds behind the ramifications of the trachea; but previously detaches some small branches, which are joined by twigs from the intercostal and from the recurrent, and form a plexus upon the anterior part of the vessels going to the lungs. This Anterior Plexus , after sending off some minute branches to the cardiac nerves and the pericardium, transmits its branches, with the bronchia^ and the bloodvessels, into the substance of the lungs. Some of the branches which proceed from the par vagum, pass down on the posterior part of the trachea, and enter into the membrane which forms it, and the 33 1 Par Fagum. — Pulmonary Plexuses . mucous glands which are upon it; and some pass to the oesophagus. When the par vagum is behind the great vessels of the lungs, a number of branches go off transversely, and are also joined by some fibres from the sympathetic. These form the Posterior Pulmonary Plexus; the ramifications from which proceed into the substance of the lungs, and are principally spent upon the ramifications of the bron- chise. It has been said,* that the small twigs, into which they divide, very generally penetrate into the small rami- fications of the bronchias, and are spent upon their internal membrane. Soon after sending off the nerves of the pulmonary plexus, the Par Vagum proceed downwards upon the oesophagus; the left nerve being situated anteriorly, and the right posteriorly. Each of these nerves forms a plexus so as nearly to surround the oesophagus, as they descend on it; but the network is thickest on the posterior side. They pass through the diaphragm with the oesophagus, and unite again so as to form considerable trunks. The Anterior , which is the smallest, proceeds along the lesser curvature of the stomach to the pylorus. Some of its fibres are spread upon the anterior side of the stomach and the lesser omentum. Others of them extend to the left hepatic, and also to the solar plexus. The Posterior trunk sends branches to surround the cardiac orifice of the stomach. Many branches are spread upon the under side of the great curvature of the stomach. Some of them pass in the course of the coronary artery to the coeliac, and unite to the hepatic and splenic plexuses; and one trunk, which is thick although short, proceeds to the solar plexus. * See Buisson, in the continuation of the Descriptive Anatomy of Bichat. 332 Different Functions of the Laryngeal , The Accessory Nerve of Willis , YV Inch has been mentioned as associated with the eighth pair of nerves, within the cranium, has a very peculiar origin. It arises by small filaments, which come off from the spinal marrow, between the anterior and posterior fasciculi of the cervical nerves, and proceeds upwards to the great occipital foramen, between these fasciculi. It commences sometimes at the sixth or seventh cervical vertebra, and sometimes about the fourth. It enters the cavity of the cranium through the foramen magnum, and proceeds up- wards and outwards, so as to join the eighth pair of nerves at some distance from its origin, and in this course it re- ceives filaments from the medulla oblongata. After approaching very near to the eighth pair of nerves, it accompanies it to the foramen lacerum, and passes out in its own separate sheath. It then leaves the eighth pair and descends towards the shoulder, proceeding through the sterno-mastoid muscle. Soon after it emerges from the cranium, it sends a ramification to the pharyngeal branch of the Par Vagum , and another to the Par Vagum itself. After passing through the upper and back part of the sterno-mastoid muscle, it terminates in the trapezius. It adheres to the ninth pair of nerves as it passes by it, and sends a twig to the sub-occipital and some of the cervical nerves. It also gives ramifications to the sterno-mastoid muscle as it passes through it. It has already been stated that the Laryngeal and Recur- rent Nerves appear to answer different purposes in their distribution to the Larynx. — When both of the recurrent nerves are divided in a living animal, the voice seems to be lost. When the laryngeal nerves only are divided, the strength of the voice remains, but it is flatter. The re- current nerves, therefore, seem essential to the formation 333 Ninth Pair of Nerves. of the voice. The laryngeal nerves are necessary to its modulation. The history of the investigation of this subject is con- tained in Mr. Haighton’s paper in the third volume of Memoirs of the Medical Society of London. THE NINTH PAIR OF NERVES. Each of these nerves arises from the groove in the medulla oblongata, between the corpora pyramidalia and the corpora olivaria. Three or four fasciculi, of distinct filaments, unite to form it. Thus composed, it proceeds to the anterior condyloid foramen of the occipital bone, and passes through the dura mater. It seems firmly united, by the cellular membrane, to the eighth pair, and to the first ganglion of the sympathetic, soon after it passes from the occipital bone. It is either connected to the sub-occipital nerve by a small ramification, or it joins a branch which proceeds from the sub-occipital to the cervical, and bends round the transverse process of the atlas. It passes be- tween the internal carotid artery and the internal jugular vein, and crosses the external carotid at the origin of the occipital artery. At this place it generally sends down- wards a large branch which is called the Descendens Noni . Passing forwards, it is on the outside of the posterior portion of the digastric muscle, and inclines downwards; but near the tendon of the muscle it turns upwards, and proceeds on the inside of the mylo-hyoideus, where it di- vides into ramifications, which, at the anterior edge of the hyo-glossus muscle, begin to enter in the substance of the tongue, between the genio-glossus and the lingualis muscles. Some of the branches of this nerve unite with those of the lingual branch of the fifth pair. Others are distributed to almost all the muscles connected with the tongue. The branch called Descendens Noni passes down in the 334 Sub-Occipital , or Tenth Pair of Nerves. course of the common carotid artery, and sends branches in its progress to the upper portions of the coraco-hyoidei and sterno- thyroidei muscles; it unites with ramifications of various sizes from the first, second and third cervical nerves, which form a bow under the sterno- mastoid mus- cle, from which ramifications go to the lower portions of the sterno hyoidei and thyroidei muscles and of the coraco-hyoidei. OF THE CERVICAL NERVES. The tenth or last pair of the head, commonly called the Sub -occipital, may be arranged with these nerves, because they arise, like them, from the medulla spinalis, and are distributed to the nerves on the neck. The sub-occipital Nerves Arise on each side of the spinal marrow, nearly opposite to the interval between the great foramen of the os occi- pitis and the atlas. Each of these nerves consists of an anterior and pos- terior fasciculus, or bundle of fibres, which pass out- wards immediately under the vertebral arteries, and form a ganglion, from which proceeds an anterior and a pos- terior branch. The anterior branch is united to the second cervical nerve below, and to the ninth nerve, or the hypoglossal, above. It also sends filaments to the upper ganglion of the great sympathetic nerve. The posterior branch is spent upon the Recti, the Obliqui , and some other muscles of the head. The proper Cervical Nerves consist of Seven Pair; of which the first six go off between the vertebras of the neck, and the seventh between the last of the neck and the first of the back. First and Second Cervical Nerves. 335 The first cervical Nerve Passes out between the atlas and the V ertebra Dentata. It originates from two fasciculi, which are connected to each other at a ganglion, and then separate into an ante- rior and a posterior branch.* The anterior branch is connected by filaments with the accessory nerve, with the ninth pair of the head, and with the upper ganglion of the sympathetic. It is also connect- ed with the second cervical nerve; and sends some branches to the muscles on the anterior part of the spine. The posterior branch, after communicating with the posterior branches of the sub- occipital and the second nerves of the neck, perforates the complexus muscle, and ascending upon the back of the head, is distributed with the occipital artery. THE SECOND CERVICAL NERVE Sends off, from its Anterior Branch , a twig which de- scends to the lower cervical ganglion of the sympathetic, and a considerable ramification to the third cervical nerve. It also sends off some twigs to the sterno- mastoid muscle, and others to join the accessory nerve. Some of its small ramifications pass down upon the external jugular vein, and others unite with the descending branch of the ninth pair of the head. A small branch is also concerned in the formation of the phrenic nerve. Two larger branches of this nerve wind found the posterior edge of the sterno- mastoid, and are spread under the integuments of the an- terior, lateral and posterior parts of the neck and lower parts of the head; they have a communication with the portio dura of the seventh pair.f — The posterior branch * This arrangement is common to the nerves of the spine. The ganglion is formed by the posterior fasciculus. t These superficial branches have sometimes been described as 336 Third Cervical , and Phrenic Nerves. of this nerve is spent upon the extensor muscles of the head and neck. THE THIRD CERVICAL NERVE Sends down, from its Anterior Branch, the principal trunk of the phrenic nerve. It also sends twigs to the fourth cervical, to the lower cervical ganglion of the intercostal, and to the descending branch of the ninth of the head. Some of its branches unite with twigs of the accessory- nerve, and others are spent upon the muscles and integu- ments of the shoulder and lower part of the neck. A small Posterior Branch is spent upon the muscles of the back of the neck. THE NERVES OF THE DIAPHRAGM Are generally denominated the Phrenic. The principal root of each of them is commonly derived from the third cervical nerve, but frequently the second and the fourth cervical nerves contribute to their formation; and they are sometimes joined by a twig which is derived from the ninth pair. Each nerve proceeds down the neck, between the rectus capitis major and the scalenus anticus, and continues along the fore part of the scalenus anticus; it descends into the thorax within the anterior end of the first rib, between the subclavian vein and the artery. It sometimes receives a twig from the fifth cervical nerve, and a twig passes be- tween it and the great sympathetic. After entering the thorax, they descend, attached to the mediastinum, before the root of the lungs. In consequence of the projection of the point of the heart to the left, the course of the left is a little different from that of the right; that of the right coming from a plexus; but they often arise directly from the Second Cervical nerve. Remaining Cervical Nerves. — Brachial Plexus. 337 proceeding in a more perpendicular direction. When they arrive at the diaphragm, they divide into many ramifica- tions, which have a radiated arrangement, and terminate on the fibres of that muscle, both on the upper and lower surface. Some fibres from each nerve are continued downward, and communicate in the abdomen with fibres from the intercostal. THE FOURTH, FIFTH, SIXTH, AND SEVENTH CERVICAL NERVES, May be comprised in one description. They pass off suc- cessively from the Medulla Spinalis, between the ver- tebras, like the other nerves. Their Posterior Branches are generally distributed to the back of the neck, and are very small. Their Anterior Branches are principally ap- propriated to the upper extremities, and are large. They generally send each a small twig to the lower cervical ganglion of the intercostal nerve, and a few small branches to some of the contiguous muscles. They are arranged and combined so as to form the network, now to be de- scribed, which is called the Brachial or Axillary Plexus ; and, in the formation of this plexus, they are joined by the first dorsal nerve. The BRACHIAL PLEXUS Extends from the lower part of the side of the neck, into the arm-pit. It commences in the following manner. The fourth and fifth cervical nerves proceed downwards, and, after uniting to each other about an inch and a half below their egress from the spine, they separate again, almost immediately, into two branches. The sixth cervical nerve, after passing downwards, di- vides also into two branches, one of which unites with Vol. II. 2 U 338 Construction of the Brachial Plexus. the uppermost branch that proceeds from the union of the fourth and fifth, and the other with the lowermost, and they all proceed downwards. The seventh cervical is joined by the first dorsal, which proceeds upwards, and unites with it at a short distance from the spine. The cord produced by their junction soon unites with one of the cords above described. As these different cords proceed downwards, they divide, and their branches again unite. The axillary artery, which passes in the same direction, is surrounded by them. In this manner the axillary plexus is often formed. The muscles about the shoulder, both before and be- hind, are supplied by the axillary plexus. Thus, it sends branches to the Sub-scapularis, Teres Major, and Latissi- mus Dorsi, behind; and to the Pectoralis Major and Minor , and the Mamma , before. It also sends off a branch called the Scapularis , which commonly arises from the upper part of the plexus, and proceeds through the notch in the upper costa of the scapula, to the supra and infra spinatus, teres minor, &c. Nerves of the Arm. All the great nerves of the arm are derived from the axillary plexus. There are six of them, which are denomi- nated The Musculo Cutaneus ; The Median ;* The Cubital, or Ulnar; The Internal Cutaneus; The Radial or Muscu- lar Spiral; and the Circumflex or Articidar. The MUSCULO CUTANEUS, or PERFORATING NERVE, passes obliquely through the upper part of the coraco brachialis muscle. Before it enters the muscle, it sends a branch to it. After leaving the muscle, it passes down the arm between the biceps and the brachialis internus, to which it also gives branches. It proceeds to the outside * Sometimes called Radial- Musculo Cutaneus and Median Nerves. 339 of the biceps, and continues under the median cephalic vein to the anterior and external part of the fore arm; along which it passes, under the integuments. On the lower part of the fore arm it divides into many branches, which extend to the root of the thumb and the back of the hand, and terminate in the integuments. The median nerve, which is one of the largest of the arm, often proceeds from the axillary plexus next to the musculo cutaneus; it passes down the arm, very hear the humeral artery, within the edge of the biceps flexor muscle, and, during this Course, gives off no branches of any importance. After passing the bend of the elbow, it proceeds, under the aponeurosis of the biceps, between the brachialis interims and the pronator teres, and con- tinues down near the middle cf the fore arm, between the flexor sublimis and the flexor profundus. At the elbow it sends branches to several muscles on the anterior side of the fore arm, and to the integuments. Among these branches is one, called the Interosseal Nerve , which passes down on the anterior surface of the interosseal ligament, with the artery of that name. This nerve sends branches, in its course, to the long flexor of the thumb and the deep flexor of the fingers. When it arrives at the pronator quadratus, it sends branches to that muscle, and, passing between it and the interosseous ligament, per- forates the ligament, and soon terminates on the posterior side of the wrist and hand. As the median Nerve proceeds downwards, it b J e= comes more superficial; and continuing among the ten- dons of the flexors of the fingers, it gives oft' a branch which is principally spent upon the integuments of the palm of the hand. This great nerve passes with the ten- dons under the annular ligament; and immediately after, while it is covered by the Aponeurosis Palmar is, and by that portion of the artery which is called Arcus Sublimis it divides into branches, which separate from each other 340 Cubital dr Ulnar Nerve. at acute angles, and subdivide so as to send a ramification to each side of the thumb, of the index, and of the middle finger; and to the radial side of the ring finger. The cubital or ulnar nerve is also of conside- rable size. It passes down on the inside of the triceps ex- tensor muscle, to the great groove formed by the olecra- non process and the internal condyle of the os humeri; and in this course it often sends a branch to the triceps, and some smaller twigs to the upper part of the fore arm. From the groove it proceeds on the anterior part of the fore arm, between the flexor carpi ulnaris and the flexor sublimis, to the wrist. At a small distance above the wrist it sends off a branch, called the Dorsalis , which passes be- tween the flexor ulnaris and the ulna, to the back of the fore arm and wrist, where, after sending ramifications to the integuments and contiguous parts, it divides into branch- es which pass to the little finger and the finger next to it. Those branches send off, in their course, many twigs which pass to the skin and cellular substance. The ulnar nerve then proceeds with the artery, over the annular ligament, on the radial side of the os pisiforme, and divides into two branches; one of which is superficial, and the other deep-seated. The Superficial divides into two principal branches, an external and an internal. The external passes under the aponeurosis palmaris; and, after sending a branch to com- bine with one from the median, and some twigs to the contiguous muscles, it subdivides into two branches, one of which goes to the ulnar side of the ring finger and the opposite side of the little finger. The other branch sends off some twigs to the muscles, and proceeds along the ulnar side of the little finger. The Deep-seated palmar branch of the ulnar nerve, passes between the muscles of the little finger, under the tendons of the flexors, and accompanies the deep-seated arterial arch in the palm of the hand, giving branches to the interossei, and other contiguous muscles. • 341 Radial, or Muscular Spiral Nerve. The radial or muscular spiral nerve is one of the largest nerves of the arm. It passes from the axillary plexus downward, backward and outward, under the tri- ceps muscle, to the external side of the o's humeri. In this course it gives off several branches to the different portions of the triceps. It also frequently gives off a large branch, which passes downwards on the outside of the olecranon, to the back of the fore arm, and continues to the back of the hand, furnishing many branches which terminate in the integuments. It then proceeds downwards between the supinator radii longus and the brachialis in- ternus. Immediately after passing the articulation of the elbow, it divides into two branches denominated the Su- perficial zx\, and vsvpav a nerve; from an erroneous supposition of the ancients, that it was formed by an expansion of nerve. Apophysis. A process of a bone; from axoQva to proceed from A synonyme of process. Arachnoides. A net-like membrane; from a spider, and likeness. Artery. From air, and mma to keep; because the ancients sup- posed that air only was contained in them. Arthrodia. A species of connexion of bones; from xpSpovto articu- late. Arytanoides. The name of two cartilages of the larynx; also ap- plied to some muscles of the larynx; from ctpo-rx net. a funnel, and £i?o 5 a shape. Vol. IT By Dr. Hooper 3 F 410 Glossary. Astragalus. A bone of the tarsus; so called from its resemblance to a die used in ancient games, from areayssAos a cockal or die. Atlas. The first vertebra of the neck; so called, because it sustains the head: from the fable of Atlas being supposed to have sup- ported the world; or from «tA xu to sustain, because it sustains the head. Azygos. A term applied to parts without a fellow, from « priv. and £uyo 5 a yoke, because it has no fellow. B. Bursa. A bag; from fivfpet: generally applied to the bursse muscosae. C. Cancelli. Lattice work; generally applied to the recticular substance in bones. Cardia. The superior opening of the stomach; from naftix the heart. Carotid. The name of some arteries of the neck and head; from napoo to cause to sleep; for, if tied with a ligature, the animal was said to be affected with coma. Car/ms. Kix.fi rot; the wrist. Clavicula. The clavicle or collar-bone, a diminutive of clavis a key; so called from its resemblance to an ancient key. Clinoid. Four processes of the sella turcica of the ethmoid bone are so called, from xA to divide. Diarthrosis. A moveable connexion of bones; from to arti- culate. Digastric. From twice, and yxrti% a belly; having two bellies. Diplue. The spongy substance between the two tables of the skull; from dmXoti) to double. Duodenum. The first portion of the small intestines; so called be- cause the ancients supposed that it did not exceed the breadth of twelve fingers; from duodcnus , consisting of twelve. Dura Mater. The outermost membrane of the brain; called dura , because it is much harder than the other membranes, and mater , from the idea of the ancients that it was the source of all the other membranes. E. Embryo. The child in the womb is so called before the fifth month, after which it is termed fatus; from epfi^voi to bud forth. Enarthrosis. An articulation of bones; from m in, and agflgev a joint or articulation. Enteric. Belonging to the intestines; from an entrail or in- testine. Epidermis. The scarf or outermost skin; from em upon, and the skin. Epididymis. The small oblong body which lies above the testicles; from e sn upon, and SiHvp os a testicle. Epigastric. The superior part of the abdomen; from est; upon, and the stomach. Epiglottis. A cartilage of the larynx so called; from estv upon, and yXa-ths the aperture of the larynx, being situated upon the glottis. Epiphysis. A portion of bone growing upon another bone, but sepa- rated from it by a cartilage: from t m upon, and tpvc* to grow. 412 Glossai' y. Epiploon. The membranous viscus of the abdomen, which covers the intestines, and hangs to the bottom of the stomach; from en-t- to swim upon. Ethmoid. From e6i to; a sieve, and eiSoj resemblance; being perforated like a sieve. F. E'ascia. An expansion, enclosing other parts, like a band; from/ to carry, and epuya to eat; because it carries the food into the stomach. 414 Glossary . Olecranon. The elbow, or head of the ulna; from o>Xn^ the cubit, and Kga.vov the head. Omentum. An abdominal viscus; so called from omen a guess; be- cause the soothsayers prophesied from the inspection of this part. O?no. Names compounded with this word belong to muscles which are attached to the scapula, as omo-hyoideus , See., from upo 5 the shoulder. Omo/ilata. The scapula or shoulder blade; from upo; the shoulder, and nXcnvi broad. Osteology. The doctrine of the bones; from e? eov a bone, and Xo'ytx; a discourse. P. Pancreas. A viscus of the abdomen; so called from its fleshy con- sistence; from nctv all, and xgs«s flesh. Parenchyma. The substance of some of the viscera was so called, from t a^yx.va to pour through. Parotid Gland; from near, and e«s the ear; because it is situ- ated near the ear. Pelvis. A bony cavity shaped like a bason; from 7riXvs a bason. Pericardium. The membrane which surrounds the heart; from sreg; around, and the heart. ' Pericranium. The membrane which covers the bones of the skull; from around, and x^.noi the cranium or head. Periosteum. The membrane which surrounds the bones; from a-£g< around, and gsvs; the diaphragm; from tp^v the mind; because the ancients supposed it to be the seat of the mind. Pia Mater. The innermost membrane of the brain, so called because it embraces the brain as a careful mother folds her child. J'leura. The membrane lining the thorax; irXev^ct the side. Plexus. A kind of net-work of vessels or nerves; from filecto te weave together. Glossary. 415 Psoas. A muscle so called; from •■pea the loin, being situated in the loins. Pterygoid process. From «r7e§v | a pen or wing, and likeness; so called from its likeness to a pen or wing. Pylorus. The lower orifice of the stomach, which opens into the intestines; from ttvXbcj to guard an entrance, because it guards as it were the entrance of the bowels. R. ; Raphe. A suture; from to sew. Renes. The kidneys, uno ra pov, because through them the urine flows. Retina. The net-like expansion of the optic nerve, on the inner surface of the eye; from rete a net. Rhomboides. A muscle so called from its shape; from p's^Sos a geo- metrical figure, whose sides are equal but not right-angled, and ados a likeness. Rotiila. The knee-pan; a dim. of rota a wheel, from its shape. S. Sacrum. A bone so called; from sacer sacred, because it was once offered in sacrifices. Salvatella. A vein of the foot, so called because it was thought that opening it preserved health, and cured melancholy; from salvo to preserve. Sanguis. The blood; ro rewtd yvi», because it preserves the body. Sartortus. A muscle so called, because tailors cross their legs with it; from sartor a tailor. Scapha. The depression of the outer ear before the anti-helix; from o-xatpn a little boat or skiff. Scaphoides. A bone of the carpus, so called from its resemblance to a skiff; from a skiff, and likeness. Sclerotic. A term applied to the outermost or hardest membrane of the eye; from o-kX^bu to make hard. Sesamoid bones. From a grain, and u2o; likeness; from their resemblance to the semen sesami. Sigmoid. Parts are so called from their resemblance to the letter 2; from 2, the letter Sigma, and ttlot likeness. Sphenoid. From e^v a wedge, and tides likeness; shaped like a wedge. Sphincter. The name of several muscles whose office is to shut up the aperture around which they are placed; from s-tpiyya to shut up. Splanchnic, From o-jrAary^ve, an entrail, 416 Glossary. Symfihysis. A connexion of bones; from to contract. T. Tendon. From ritvu to extend. Thorax. The breast or. chest. Thyroid. From a shield, and likeness; shaped like a shield. Trachea. The windpipe, so called from its roughness; from rough. Trochanter. A process of the thigh-bone, so called from t^o; a wheel. U. Ulna. A name for the cubit; from aXevti the cubit. Ureter. The canal which conveys the urine from the kidney to the bladder; from a%ov urine. Urethra. The passage through which the urine passes from the bladder; from xgov the urine. Uvea. The posterior lamina of the iris, so called because in many animals it is of the colour of unripe grapes; from uva an unripe grape. Uvula. The conicle substance which hangs down from the middle of the soft palate: so called from its resemblance to a grape. A dim. of uva a grape. V. Valves. From valve folding doors. Vertebra. The bones of the spine are so called; from verlo to turn. X. Xi/dioid. So called from the resemblance to a sword; from a sword, and sidog likeness. Z. Zygoma. The cavity under the zygomatic process of the temporal bones; from £uyos a yoke. INDEX. A. Abdomen Abernethy, Mr. statement by him in the London Phi- losophical Transactions case of termination of the vena porta- rum in the vena cava below the liver description by, of the menseteric gland of the whale Absorbent vessels - of the lower extremities of the head and neck of the abdomen and thorax - of the arm and upper part of the trunk Acetabulum ..... Accessory nerve of Willis - Acini of the liver .... Adhesion of the lungs to the thorax - - - Adipose artery - membrane - Adjustment of the center of gravity Alphabetical arrangement of the muscles Alveolar artery - - - - Anastomotic artery ..... Andre, M. St. - - Animal motion, question respecting ... Aorta ...... table of the, exhibiting the distribution of its branches - Appearance of the caecum and colon Appendix of the diaphragm Aqueducts of the ear Aqueous humour VOL. II. Vol.l. Page 98 387 395 255 398 160 202 381 357 Vol.ll. Page 81 58 135 364 361 366 382 371 383 332 129 72 271 239 283 22.9 288 115 3 G 418 INDEX. Arbor vitae - Arm, bones of the - nerves of the - Arrangement of the jejunum and ileon Arteries, general account of their distribution Articulations, general account of - Astragalus - articulation of the Auditory nerve - Auricular artery - Axillary artery - vein .... Azygos, vena .... Vol.I. Page 321 109 263 142 284 380 B. Baillie, Dr. ... Ball of the eye ----- 33 7 Barclay, Dr. ------ Basilar artery - Basilic vein ------ Basis of the cranium 59 brain - - - - - 32 1 Baynham, Dr. of Virginia, his method of injecting the rete mucosum ----- 394 Bell, C. - - - - - 359 Bell, John, observation of - Berlin, royal academy of sciences of - - - 400 Berzelius, professor of chemistry at Stockholm, his experiment on secretion - Bichat, M. opinion embraced by, respecting the ex- tent of the retina - - - 351 of the pores of the cuticle - - 401 doubts of, the existence of the rete muco- sum in the tongue - - - his solution of a problem doubts of, respecting the muscularity of arteries - on the structure of arteries Biliary duct ------ Biliary and pancreatic ducts, orifices of - Bile Bladder, gall - Vol.II. Page 338 111 227 236 252 299 292 76 252 249 299 136 405 21 73 220 220 135 111 137 136 INDEX. Vol.T. Page 419 Bladder, urinary - Blood ...... colouring matter of the - Bloodvessels in general - of the tongue - - - - of the abdomen - - - Boerhaave, K. experiments of Bones, structure of formation of - terms used in the description of - Bostock, Dr. ------ his assertion respecting the blood Boyer, M. Brachial plexus of nerves ... construction of the - Brande, Mr. on the serum of the blood - his chemical researches respecting the blood - Brain, basis of - - - - - 321 commissures of - - - - 317 middle artery of nerves of - - - - 32 1 British anatomists on the spleen - - - Brodie on the source of motion in the heart - Bronchi®, black glands on Bronchial artery - Bucquet, M. - Buisson, M. - Bursae mucosae - - - - 265, 292 Vol.H. Page 157 394 396 215 23 86 386 70 394 162 337 338 394 399 246 147 80 63 262 398 331 Caecum ^ position of Camper Canals, semicircular Capsular arteries veins Cardiac plexus Carlysle, Dr. Carotid arteries Carpus Cauda equina 378 155 119 328 115 126 211 271 303 355 229 420 INDEX. Vol.I. Vol.II. Page Page Cavallo, Tiberius ... . 397 Cavities of the nose ... . . 53 Cavity of the cranium ... - 56 tympanum - - 366 Cellular membrane ... . 384 Cerebellum - - . 320 Cerebrum .... . 310 Cephalic vein ... - - 298 Change of colour in negroes, instance of - - 395 Changes of the rete mucosum in white persons - 396 Change of position in the stomach - 96 Choctaw Indians, custom of - - - 62 Chorda Tympani - - - - - 373 Choroid coat - - - - - 341 Ciliary ligament - - 343 processes - - - 348 Circulation in the placenta, object of the - 213 Circumflex artery of the os ilium - - 280 vein - - 305 Clavicle .... - - 102 Coat of th>e liver .... - 129 Cochlea - - - - 376 Colon, structure of 117 valve of the ... - - 1 18 Cooper, Mr. Astley ... - 83 Cornea .... - - 339 Coronary veins - - - 290 Corpora albicantia of Willis - 323 Corpora cavernosa - - • 1 80 cells of the - 181 lutea ... - - 202 Corpus spongiosum ... - 182 structure of - - 183 Corpuscula Arantii ... - 55 Crassamentum ... - - 395 Cremaster muscle - - 169 Cricoid cartilage ... - - 31 Cruikshank, Mr. Wm. his opinion respecting the ves- sels between the rete mucosnm and cutis ... 392, 394 his experiments favourable to the idea of the motions of the heart being in- dependent of the brain - 78 INDEX. 421 Yol. I. Vol.n. Page Page Cruikshank, Mr. Wrn. his ideas relative to the origin of the lacteals ... 106,363 his description of the appearance of the absorbents of the kidney * - 371 his injection of the absorbents of the pancreas ... 377 his demonstration of those of the lungs 379 Crural nerve ..... 345 Crystalline lens ..... 355 Cubital nerves ..... 334 Currie, Dr. (of Liverpool) ... 385 Cuticle ...... 398 Cuticle, pores of - - - - * 399 peculiar permeability of - - - 401 separation of the - - - - 403 chemical qualities of the ... 404 Cuvier, M. his opinion respecting the vascular con- volutions of the corpus spongiosum of the horse - - - - 191 D. Daingerfield, Dr. his experiments - - 385 Delile, M. his memoir on the organs of absorption in mammiferous animals ... 38 7 Desault, M. his ideas respecting the structure of the spleen .... 145 his experiment respecting the frontal sinus 13 Diaphragm - 202 nerves of the - 336 Digital arteries ..... 260 Dorsal nerves ..... 342 Dorsey, Dr. John S. - - - - - 71 Duct, thoracic ..... 37 7 hepatic - - - - - 132 cystic ..... 135 Ductus venosus - - ... . 212 Duodenum ..... 302 Dupuytren, M. inference from his statement in a volume of the proceedings of the Na- tional Institute, respecting the nerves of the lungs - Dura mater 305 72 422 INDEX. E. Ear - bones of the - - - . Ellis on respiration - Elbow, articulation of the - Emulgent arteries - veins - - - - Epidermis ..... Epididymis - Epigastric artery .... vein - Epiglottis ..... Eustachian tube - External pudic arteries - External iliac arteries - iliac veins .... Eye, description of the orbit of the parts auxiliary to the - ball of the - humours of the ... dissection of the » effect of the solution of nitrate of silver on hyaloid coat of the - Vol.I. Page 361 370 274 - 398 368 51 331 337 352 358 the - 360 Vol. II. Page 70 271 303 166 279 306 30 281 279 305 F. Face ... Facial artery Fauces, isthmus of the Fallopian tubes, structure of the Falconer, Mr. on the spleen Falx ... Femoral artery vein Foetus, head of - thorax of - trunk of - extremities of Fibula ... Fimbriae Fingers articulation of the 32 215 29 200 147 - 307 280 306 63 65 101 - 152 136 201 129 - 277 141 Foot INDEX. 423 Yol.I. Vol. II. Page Page Fontana, Abbe .... - 78 on the structure of the nerves 150 on the colour of the blood - 396 Foramen caecum - - - - 22 lacerum - - 60 ovale - 50 thyroideum - - 98 Forearm - - - - - 113 interosseous ligament of the - 286 Fornix - 315 Fossa ovalis - - 74 Fourcroy, M. - 385 French anatomists, their peculiar opinions respect- ing the course of the blood in the foetus - - 73 Fyfe, Mr. on the villi .... 107 G. Gall, Dr. ------ 326 Ganglions - 312 Gastric liquor - - - - - 100 Gavard, M. proposition of ... 114 Generation, female organs of - - - 192 male organs of ... 166 Glands, inguinal ..... 368 Glands on the bronchiae .... 63 of the mesentery - - - - 115 of the neck .... 332 Glandulae Buccales - 15 Brunneri .... 104 Peyeri - - - - - 104 Molares .... 246 Renales - - - - - -150 Gluteal artery - - - - - 277 Goodwin, Dr. his explanation of the effects of venous blood on the heart ... 73 Graff De, his successful investigation of the testicle 174 Grew, Dr. - - - - - 400 H. Haighton, Mr. a dissection of the ear recorded by - 383 essay of - ..... 36 Haller, M. on muscular fibres - - 155 remarkable sentiment of 42 424 INDEX. Yoll. Page Haller, M. inclined to the opinion of Ruysch on the spleen .... a cavity in the glandulae renales frequently found by - his publication in the Philosophical Trans- actions of London - - - on the testicles of the foetus - his great attention to the arterial system his observations on the absorbent vessels Hand - - . . . -119 Hatchet, Mr. Charles - Heart, description of the Hepatic artery ..... veins - Hewson, Mr. William, on the villi his opinion respecting the spleen on serum - on the crassamenlum - on the colour of the blood on the structure of glands Hewson, Dr. T. T. his experiments on the blood Home, Mr. Croonian lecture of - - - 160 his assertion respecting the membrana tympani .... 368 confirmation of the account of the vesicles in the spleen ... his questions relative to the blood Hottentots, female, peculiarity of the Humboldt, M. on the experiments of Legallois ' - Humeral artery - Hungarians, peculiarity of the Hunter, Dr. William .... 387 opinion of, on the villi - his opinion respecting the structure of glands - belief respecting a part in glands not in- jected in his preparations his ideas of fluids which appear in vari- ous cavities of the body - Hunter, Mr. John - his opinion respecting the vascular struc- ture of the corpus spongiosum urethrae Vol.ll. Page 146 151 174 211 251 362 395 50 266 301 106 147 394 396 397 402 396 148 405 208 79 255 211 71 106 403 403 404 100,177 191 INDEX. 425 Vol.T. Vol.lL Page Page Hunter, Mr.’ John, fact established by experiments of 387 on the structure of arteries - - 219 on the colour of the blood - 397 Hypogastric artery ... - - 274 vein - - 304 I— J. Iliac arteries - - 273 veins .... - - 304 Injected preparations, examination of - 261 Instances of peculiar arrangement of veins - - 307 Intercostal arteries ... - 263 veins ... - - 292 Interosseal artery ... Internal basis of the cranium - 56 259 Intestines .... - 103 division of - . - 108 Iris ..... Ischiatic artery ... - 344 277 Jejunum and ileon ... - 111 Jones, Dr. .... - - 220 Jugular veins, internal - - 395 external - - 397 Jussieu, M. account by, of a female born without a tongue .... - 27 K. Kidneys - - - 152 cortical and tubular portions of the - 155 nerves, lymphatics, and coat of the - - 156 absorbents of the - 371 Klapp, Dr. .... Knee, articulation of the ... ~ - • 280 385 L. Labia externa Labyrinth .... - . - 374 193 contents of the . - 379 functions of the different parts of - 383 Laennec, M. - - - - . Lachrymal gland - - - 334 129 sac ... *» • 335 Vol.IT. 3H 426 i INDEX. Vol. I. Page LaCteals - Larynx Legallois, M. experiments of, on the source of the motion of the heart - Lieberkuhn, M. - Lieutaud, M. ..... Ligaments - - - - 28(5 Liver ...... absorbents of the .... Lumbar arteries ..... veins ..... nerves ..... plexus - * - Lungs, ...... structure of absorbents of - Lymphatics in the spermatic cord of the uterus .... Vol. IF. Page 372 31 79 106 162 125 375 273 304 343 344 64 66 379 169 204 M. Magendie, M. experiments of, on the organs of ab- sorption in mammiferous animals Malformation, cases of Malpighi, M. on the structure of the spleen on the structure of glands Mammary artery .... Marcet, Dr. Mascagni, M. on the villi ... on the absorbents of the kidney assertion of, in his great work on the absorbent system his ideas respecting the structure of glands - Mastoid cells ..... 369 Maxilla inferior - - - - - 42 Maxillary arteries - - - nerves ..... Meatus Auditorius Externus ... 364 Interims ... 379 Meckle, Professor, his opinion respecting the outlets of perspiration - - 400 on the nerves of the face 387 71 144 402 218 71 107 371 403 403 236 319 32-7 INDEX. 427 Vol. I. Page Mediastinum - Median nerve - vein - Meibomus, glands of - Membrane, adipose - Schneiderian - extent of - distribution of Membrana tympani - observations on the Menghini, Vincentius, his experiments tending to es- tablishment the opinion, that the colour of the blood depends Upon iron - Mesentery ------ construction of root of - Mesenteric artery - vein - Metacarpus - Metatarsus ------ Middle hsemorrhoidal vein - sacral vein - - - - - Monro, Dr. on the Bursse Mucosa on the iris - Monro, Dr. opinion of, respecting the extent of the retina - - - - - his opinion respecting the villi observation of, on the epididymis Morgagni, M. ventricle of Motion, muscular, phenomena of - of the skeleton - Mouth ------ internal surface of the - - - Mucus of the nose - of the bladder - Mussey, Dr. - Muscles, alphabetical arrangement of - N. 334 395 5 9 10 367 373 110 111 113 124 148 265 346 351 158 159 Nails - Neck, arteries of the absorbents of the 255 405 Vol. II. Page 45 339 299 398 270 302 276 304 106 174 34 14 1 5 12 161 385 251 382 428 INDEX. Vol.I. Yol.il. Page Page Neck, muscles of the - - - =210 Nerves, general account of - 310 Nichols, Dr. F. - - - - - 147 Nose ...... 1 cavities of the - - - 53 4 nerves of 6 sinuses of - 12 O. Obturator artery ... Occipital artery - Oesophagus ... Olfactory nerve - Omentum, origin and arrangement of varieties in the appearance of Ophthalmic artery - - - nerve - - - - Ovaries - - - - Os frontis - - - - 14 Ossa parietalia - - - 16 Ossa temporum . - - - 18 Os occipitis - - - 21 Os ethmoides - - - 23,409 Os sphenoides - - - 27 Ossa maxillaria superiora - - - - 32 Ossa nasi - - - - 36 Ossa unguis = - - - • 37 Ossa malarum - - - 37 Ossa palati - - - - 38 Ossa spongiosa - - - 41 Os hyoides - - - - 50 Os sacrum - - - 79 Os coccygis - - - - 81 Os ilium - - - 94 Os ischium - J - - - - 95 Os pubis ' - - - 97 Os humeri - - - - 109 Os femoris - * - 131 Os calcis - - - - 143 Os naviculare - - - 145 Os cuboides - - - - 145 Os cuneiforme - - - 146 276 235 93 315 123 124 243 318 201 INDEX. 429 Vol.I. Page 139 93 289 Palpebras - 332 Pancreas ------ Pancreatic duct - - - - - Pancreas enlarged, symptoms of - Papillae of the tongue .... Par Vagum ------ Parotid gland - - - - - Patella - - - - - ' - Pears, Mr. C. account by, of a woman in whom the ovaria were deficient Peculiarity of the liver Pelvis - - . - ligaments of the absorbents of the Perforating arteries - Pericardium - Peritoneum - Periosteum - Peroneal artery - nerve - - - Pharyngeal artery, inferior - Pharynx, structure of the Phrenic artery - vein - Physick, Dr. his opinion respecting incisions of the cornea ------ Pia mater ----- Pineal gland - Pleura, arrangement of the ... Plexuses of nerves - - - - - Plexus choroides - - - - Pomum Adami - - - - - Popliteal artery - Pores of the cutis vera Portarum vena Portio Dura ------ Posterior iliac artery - Poupart’s ligament, method of preparing it for exa- mination - ... - - 192 Priestley, Dr. - Primitive iliac arteries - 340 306 318 !16 - 391 VoL II Page 139 140 140 21 328 25 208 135 371 282 49 88 286 349 234 38 265 301 45 312 32 283 13L 325 2 77 70 27S 430 INDEX. YoLI. Pag? Primitive iliac veins Proven§al, Dr. J. M. Pudic artery ... Pulmonary arteries and veins plexus Puncta Lachrymalis Pylorus - Q- Questions, respecting perspiration ... 400 the structure of the spleen Questions of Mr. Home - R. Radial artery - nerve - Radius - Reticular membrane ... Reaumur, M. - Rectum, position and structure of - Renal arteries .... Reproduction of nerves ... Rete mucosum - Retina - Ribs - - - - Ridley, circular sinus of Rima glottidis - Rivinus, professor, erroneous opinion of Rolland, M. - - - - Rousseau, Dr. - Rush, Dr. James - Ruysch, M. - preparation of - on the structure of the spleen his opinion on the structure of glands 116 387 393 3-50 83 309 368 343 S. Sabatier, M. idea of, respecting the bloodvessels and the colour of muscles - - 156 theory of, relative to the foetal circula- tion - observation of, on the stomach Vol.M. Page 304 72 278 60,308 332 101 148 405 25 7 34 1 100 120 271 314 34 27 385 124 15 144 402 74 302 INDEX. 431 Vol.I. Yol.II. Page Page Sabatier, M. supposition of, respecting the rectum 119 Sacral artery ... - - 224 Saliva - - - 26 Salivary glands ... - - 24 Scapula .... - - 104 articulation of - - 271 Sciatic nerve - - - - - 348 plexus ... - 347 Serum - - - 394 Scheele, Mr. ... - - 70 Schneider, Dr. Conrad - - 5 Sheldon, Mr. John - - 106 Shippen, Dr. J. G. - - 114 Sims, Dr. - - - 374 Skin, vicarious affections of the - - 407 Sone, De La, opinion of, on the spleen - - 146 Soemmering, interesting discovery of - - 351 idea of, respecting the papillae of the tongue - - •22 opinion of, on the villi - - - 107 statement of, respecting injections of absorbent vessels - - 364 Smelling, function of - - - 11 Spallanzani, Abbe - - 70 dissertation of - - 100 Spheno-Palatine artery - - 239 Spleen, general account of - - - 141 absorbents of - - - 376 Spinal marrow ... - - 327 arteries of the - - 329 veins of the - - - 333 Spermatic arteries - - 271 veins ... - - 303 Splenic artery ... - - 267 Stewart, Dr. J. Bradner - - 385 Stiles, Sir F. H. E. -■ - 397 Stomach, general view of the - - 95 absorbents of - - - 374 Structure of ganglions - - 307 of glands •- ' - 400 Subclavian arteries - ■ - - 247 veins - - 302 43-2 INDEX. voi.i. Voi.it. Page Page Superior mesenteric Artery - - - - 268 vein - - - 302 Superior vena cava - -• - . . 391 Sympathetic nerve - - - 351 T. Tears . . . - 335 Teeth - . - - 45 Temporal artery - - . - 240 Thcbesius, a German Professor; , assertion of - 58 Thigh ■» - - ■ 130 Thoracic duct . . 377 Thorax . _ . . 41 Throat - . . . 29 Thymus gland - - - - 67 Thyroid artery, superior - - - 232 inferior - - - - 248 Tongue - - - - 18 Torre, Father de la - - - - - 397 Trachea - - - - 62 Tunica Arachnoidea - - - - - 305 Tunica Conjunctiva - - 333 Tunica Sclerotica - - - - 338 Tunica Choroides - - - 341 Tunica Hyaloidea - - - - 353 fluid in the - - - 354 Tympanum, cavity of the - - - - 366 foramina and protuberances of the - 369 U. Umbilical vessels - - - - 211 Ulna - - - 114 Ulnar artery - - - - 259 nerve - - - 340 Urine - - - - 164 Uterine artery - - - 277 Uterus - - - - 197 V. Valve of Eustachius - - - 53 Vieussens - - - - 321 Valvulae Tricuspides - - - 55 INDEX. 433 Vol. I. Vol. II. Page Page Valyulae Mitrales - - 56 Semilunares - 55 Vas Deferens ... - - 175 Vauquelin, M. 39S Vena azygos - - - 292 Vena cava, superior - 291 inferior ■ - - 300 Vena Galeni - 319 Vena portarum ... - - 302 Venae vesicales ... - 304 Ventricles of the brain . ■' - 313 Veins, particular distribution of - 289 Veins of the heart - - 290 Vertebrae, connexion of, with the head - s 266 articulation of, with each other - 267 Vertebrae, true ... - 66 Vertebrae, false - - - 79 Vertebral artery ... \ - 249 vein - - - 306 Vesalius, M. his method of examining the brain 317 Vesication, causes of - - - 402 Vestibule ... - - 376 Vidius, professor, reputed discoverer of the pterygoid foramen - - 31 Vieussens, assertion of - - - 58 Vitreous humour ... - 353 W. Wells, Dr. ... - - 399 Wollaston, Mr. ... - 405 Winslow ... - - 73 Wilson, James, Esq. - 197 Willis, accessory nerve of - - 332 Wrist, articulation of - 275 3 I Vol. II. ERRATA. VOLUME I. Page 70.. ..8th line from below, for cervical read vertebral. 178.. . .1st line, for palati read palate. 191. . ..7th line, for their facia read thin facia. 214.. ..10th from below, l'o r first vertebra of the neck read v ertebrce of the neck. 267.. . lith line, for bones of the condyles read bases of the condyles. 323.. .. 10th line, for Pons Variolii read Pons Varolii. 345. . ..5th line, for plain read plane. 340, 354, 355, 356, for lamen read lamina — for lamina read laminae. 375 ...3d line from below, for solid read hard. 384 ...4th line, for these read them. 394.. .. 10th line from below, for as infection read as an injection. •407.... (title) for vicarious connexion read vicarious affections of the skin. VOLUME II. Page 94.... 19th line, for found read formed. 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