(A? CORNELL UNIVERSITY THE 3Ilotuer Hetcrinarg ffiibrarg FOUNDED BY ROSWELL P. FLOWER for the use of the N. Y. STATE VETERINARY COLLEGE 1897 QP 36-j-g5"™"""'™"'*>"-ibrary A oompend of anatomy and physiology.lllu 3 1924 001 040 967 Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924001040967 A COMPENI^ OF ANATOMY AND I^HYSIOLOGY ILLIJ^RATED BY THE NEW M^ODEL ANATOMICAL MANIKIN INCLUDING A KEY, A GLOSSARY OF MEDICAL TERMS, AND. INCIDENTAL NOTES ON PATHOLOGY EDJTED^D COMPILED FROM STANDARD WORKS BY M. C. TIERS -nf^hin NEW YORK FOWLER & WELLS COMPANY 775 Broadway ^ 1891 {5F IT, 1891, : coptbight, 1891, by Fowler & Wblls Co., Ke'^ York. INTRODUCTION. The design and construction of " The New Model Ana- tomical Manikin " is the result of a life-long study of the subjects involved, by Which I have become familiar, not only with human anatomy and physiology as exhibited in the natural subject, but also as illustrated in the great standard worlds of both American and European authors. Being an artist by profession, and having made anatomy and kindred subjects specialties for many years, I have in this work utilized ray ample resources to produce in compact portable form a system of illustration, at mod- erate cost that obviates the necessity for the numerous separate expensive charts that have hitherto been deemed ' mecessary. In preparing the drawings for this work I have spent large portions of time in the medical college, hospital, and general libraries of this city, and have thus had access to the best works on the subject now extant. Among the well-known anatomists whose illustrations have contrib- uted to the composition of this work I name the following: Weisse, Cloquet, Bouveret, Caldini, Brdl, Tiedeman, 4 INTRODUCTION. liangenbeck, Walter, Brechet, Soemering, Arnold, Stilling, Wallach, Meohel, Bock, Faessebeck, Scarpa, Asch, Peipers, Eisher, Oesterreicher, Camper, Hannover, Santorini, Kier- ,nan, Wagner, Laiith, Mascagni, Bougery and Jacobs; Hirschfeld, Gray and Jeancon. The charts of which this manikin is composed have been so arranged that the different branches of anatomy and physiology may be studied, each separately from the others, as well as in their proper relations to each other. Most anatomical charts, even in the best works, are de- signed frequently, if not generally, to exhibit the construc- tion of the special organ or organs represented, rejecting adjacent organs not necessary to such representation. On this account the student often finds it necessary to learn the relations of organs to each other from other sources. It has been the purpose in this manikin to obviate as far as possible this difficulty. Thus the bones, muscles, the internal viscera, the main blood-vessels throughout the — entire organism, and the brain and nervous system, are each exhibited so as to be studied separately or together, all drawn with anatomical accuracy; and, where it has seemed important, magnified appended manikins of special organs, such as the stomach, heart, kidney, eye, ear, and others, are arranged in the natural relation of their parts around the border. To aid the student in the study of the subject there INTRODUCTION. S follows, not only a complete key to all its parts, but a gen- eral description of anatomy and physiology derived sub- stantially from the standard scientific works in use in American medical institutions. Of these, " Gray's " and "Quain's Anatomy," and "Dalton's" and "Flint's Physi- ology," have been prominent. In anatomical construction I have not followed in a ser- vile way the charts and plates from which I have drawn my material, but have, rather, accommodated them to the descriptive anatomy at hand in the standard works which I have endeavored faithfully to illustrate. In the composition of this manual it has been the pur- pose not only to furnish a detailed key to the manikin, but also to give a general outline of physiology or the func- tional qualities of the various organs represented. This often involves reference to matters not easily illustrated to the eye, but of much importance in understanding the manikin in its suggestiveness. Most of the matters of this sort are condensations from the well-known medical authorities already mentioned. To obviate any difficulty that might arise from the un- avoidable use of medical terms, I have also furnished a glossary, giving full explanation of such terms employed in this manual, as well as of others in general use in med- ical works. INDEX TO THE C H K RXS THE NEW MODEL ANATOMICAL MANIKIN. No. I. — External Muscles of Face and Neck. 1, Frontal portion of Occiplto-Frontalis ; 2, Attolens Aims ; 3, Attrahens Auris (Temporal fascia). 4, Occipital portion of Occipito frontalis ; 5, 6, Orbicularis palpebrarum ; 7, Levator labii superioris alsequi nasi ; 8, Zygomatic minor ; 9, Zygomatic major ; 10, Orbicularis oris ; 11, Depressor labii inferioris ; 13, Masseter ; 13, Stemo-cleido mastoid ; 14 to 15, Splenius, Levator anguli scapulae, Scaleni; 16, 17, Trapesiiis; 18, Platysma-myoides; left side. No. II. — Anterior view of muscles of right side of body. 19, Platysma-myoides ; 20, PectoraJis major ; 21, Deltoid ; 22, Setratus magnus ; 23, 24, External Oblique ; 25, Lineaalba; 26, Pouparts ligament ; 27, Facia lata f emoris. No. III. — Anterior view of muscles of right arm with sujierficial - , veins. 28, Biceps ; 29, 30, Internal head of triceps ; 31, Supinator longus ; i. Cephalic veiu ; j, BasiUo v.; k, Posterior ulnar v.; 1, Anterior ulnar v.; m. Median v.; n, Eadial v. No. IV". — Anterior view of muscles of right hand. 1, 2, 3, 4, Digital and Palmar veins commtmicating with the Radial and Ulnar vein^in the fore arm, a, b, muscles and tendons of the palm. 8 THE MODEL MANIKIN PHYSIOLOGY No. v.— Anterior view of muscles and superficial veins of right leg and foot. 46, Adductor longus muscle ; 47, Sartorius m. 48, Adductor magnus m. 49, Vastus externus m. 50, Rectus femoris m. 51, Tibialis Anticus m. 53, Extensor digitorum communis longus m. ; o, Long Saphenous vein ; p. Branches of same communicating with each other and with the deep veins and the short saphenous vein on the posterior side of the leg ; s. Branches on the dorsum of the foot arising from its arch and communicating with the long and short saphenous veins ; q, Venous arch on the dorsum connecting the long and short saphenous veins, and r, receiving branches from the toes. No. VI. — Anterior view of deep muscles of left side of body. 32, Os humeri ; 33, Coracio bracialis muscle ; 34, 36, Short head of the Biceps muscle ; 35, Pectoralis minor m.; 37, Ex- ternal oblique abdominis m.; 38, Rectus Abdominis m.; 39, Obliquis internus m.; 40, Head of the Rectus Femoris m.; a, Clavicle os ; b, Manubrium of sternum ; c. Second rib cartilage ; d. Third rib cartilage ; e. Fourth rib cartilage ; f , Sternum os ; g. Symphisis pubes ; h. Anterior superior spine of Ilium. No. VII.^Muscles of the left arm. 41, Biceps muscle; 43, Internal head of Triceps m.; 43, 44, Supinator longis m. ; 45, Flexor carpi radialis m. No. VIII. — Deep muscles of left leg and foot. 53, Tendonous portion of vastus externus m. ; 54, Pictinseus m. ; 55, Adductor longus m.; 56, Adductor magnus m.; 57, Vastus externus m.; 58, Ligamentum Patella. 59, 61, Ex- tensor digitorum communis longus m.; 60, Peronseus longus brevis ; t, Patella os ; u. Tibia os. _ _ I No. IX. — Muscles and tendons of lef c hand. 1, Abductor poUicis Muscle ; 2, Palmaris brevis m.; 3, Tendon- ous extensions of muscles of arm j 4, Muscular fibres crossing each other on the fingers. No. X. — Anterior view of bloodvessels of face and neck. 1, Carotid arteries; 3, Internal jugular veins; 3, External ■jugular veins ; 4, Anterior jugular veins ; 5, Facial veins ; 6, External maxillary arteries ; 7, Angularis Art. ; 8, Tem- jjoralvein; 9, Middle temporalv.;10, Ophthalmic cerebralv.; 11, Temporal profunda from internal maxiUary artery ; a, Occipito frontalis m. ; b, Orbicxilaris palpebrarum m. ; c. Zygomatic minor m.; d, Zygomatic major m.; e, Levator labii superioris proprius m.; f , Masseter m.; g, Triangularis menti m.; h, Quadratus menti m.; i, j, Orbicularis oris m.; k, Levator menti m. ; m, Larynx and Trachse ; n, Thyroid gland. No. XI. — Thorax showing lungs and heart between the ribs. 1, Sternum ; 2, Clavicle ; 3, First rib ; 4, Tenth rib ; 5, Lungs ; 6, Heart ; 7, Liver ; 8, Stomach ; 9, Spleen. No. XII. — Bloodvessels of left side of^face and anterior section of heart and lungs. 1, Vertical section through the heart; 2, Bight auricle; 3, Right ventricle ; /4, Left auricle ; 5, Left ventricle; 6, Arch of aorta ; 7, Left carotid artery ; 8, Left subclavian artery ; 9, Bight common carotid artery ; 10, Arteria innominata ; 11, Left pulmonary artery ; 12, Left pulmonary vein ; 18, Bronchial tubes : 14, Ascending vena cava ; 15, Descending aorta ; 16, Descending vena cava ; 17, right vena innom- inata; 18, Left vena innominata; 19, Internal jugular veins ; 20, External jugular veins ; 31, Anterior jugular veins ; 22, Bight inferior thyroid v.; 28, Bight external. jugvdar v.; 24, Superior thyroid artery ; 35, Anterior facial v.; 26, External maxiUary artery ; 27, Superficial temporal art.; 28, Temporal vein ; 29, Occipital v.; 30, 31, Branchesof temporal vein ; a, Os frontis ; b. Orbicularis palpebrarum ; c. Temporal muscle ; d. Occipital m. ; e. Parotid gland ; f , Larynx ; g, Trachea. No. XIII. — Anterior view of stomach and intestines, the omentum having been removed. 1, Internal coating of Stomach ; 2, Portion of pancreas and its duct opening into the duodenum ; 3, Section of duo- 10 tHE MODEL MANIKIN PHYSIOLOGY denum; 4, Upper portion of small intestines or jejunum; 5, Lower portion of smaU intestines or ileum ; 6, Termina- tion of the ileum where it opens into the ascending colon ; 7, Ascending colon ; 8, Transverse colon : 9, Descending colon; 10 Rectum; 11, Bladder; 12, Right and left iliac arteries and veins ; a. Portion of psoas muscle ; b, Pyloric orifice of stomach ; c. Cardiac orifice opening into the oesophagus. No. Xrv. — Anterior and posterior view of stomach and liver. 1, Liver as it covers the pyloric end of the stomach ; 3, Car- diac end of the stomach not covered by the liver. Also Posterior view of 1 and 3. No. XV. — Lateral view of section through middle of skull, face and neck, showing internal structure. 1, Internal view of skull ; 3, Bones of skull covered by scalp ; 3, Section of superior maxillary bone ; 4, Cervical vertebra; 5, Nasal passages ; 6, Opening from the eustachian tube ; 7, Tongue ; 8, Sublingual gland ; 9, Submaxillary gland ; 10, Cavity of the mouth approaching the pharynx; 11, Larynx ; 13, Trachea; 13, Cervical plexus of nerves; 14, CEsophagus; 15, 16, Vena innominata right and left ; 17, Thoracic duct. No. XVI. — Deep viscera of thorax and abdomen. 18, Internal view of ribs cut off in front ; 19, Arch of Aorta ; 20, Right azygos vein ; 31, Left azygos vein; 33, Uniting with the right azygos ; 38, 34, Intercostal veins and arteries; 35, Descending Aorta ; 36, Ascending vena cava ; 37, Right and left sections of diaphragm ; 28, Section of right side of liver with its bloodvessels ; 39, Hepatic veins entering the vena cav&, ; 30, Portal vein and its branches, showing its termination in the liver ; 31, Hepatic artery ; 33, Splenic artery ; 33, Splenic vein ; 34, Gall ■ bladder ; 35, Vertical section of spleen ; 36, Pancreas ; 37, Left kidney ; 38, Ver- tical section of right kidney ; 39, Suprarenal capsules ; 40, v t, . , Superior mesenteric vein ; 41, Inferior mesenteric vein ; '43, Superior mesenteric artery; 43, Inferior mesenteric - a,rtery ; 44, Ureters ; 45, Section of left side of intestines : INDEX 11 46, Section of right side of intestines ; 47, Left renal vein ; 48, Left renal artery; 49, Right renal artery ; 50, Eight renal vein ; 51, Mesenteric glands and vessels ; 53, 53, Bight and left iliac arteries ; 54, Left iliac vein ; 55, Right Uiac vein ; 56, Right internal iliac artery and vein ; 57, Right external iUac artery ; 58, Bladder ; 59, Psoas muscles ; 60, 61, Right and left femoral arteries and veins ; 62, Origin of profunda artery and vein ; 63, Branches of profunda artery and vein; 64, Anterior crural nerve ; A, Outline of head of femur. No. XVII. — ^Arteries of right arm with their vena comites. 65, Subclavian artery ; 66, Subclavian vein ; 67, Axillary vein; 68, Axillary, artery ; 69, Brachial artery and two vena comites ; 70, Ulnar artery and two vena comites ; 71, Radial artery and two vena comites ; 73, Anterior interosseous artery and veins ; 73, Cephalic vein ; a, Deltoid muscle. No. XVIII. — .Arteries and deep veins of right hand. 1, Ulnar artery ; 3, Superficial palmar arch ; 3, Digital branches from the deep and superficial palmar arches ; 4, Deep palmar arch ; a, Tendons connecting the fingers with muscles of the fore arm ; b, Flexor brevis, poUicis. No. XIX.— Arteries and deep veins of right leg and foot. 1, Femoral artery ; 3, Location of femoral foramen where the artery passes behind the femur ; 3, Popliteal artery ; 4, In- terosseous space between the tibia and fibula, where the popliteal artery bifurcates and one branch comes in front and becomes the anterior tibial artery ; 5, Anterior tibial artery ; 6, Metatarsal artery and veins ; 7, Branches from the metatarsal to the toeS with double vena conutes ; . 8, Posterior tibial artery and veins ; 9, Peroneal artery and veins ; 10, Profunda artery ; 11, External circumflex artery ; 13, Femoral vein ; 13, Popliteal vein ; 14, Muscular branch of same ; 15, Outline of femur ; 16, Outline of tibia ; 17, Tarsus ; 18, Metatarsus and phalanges ; 19, Fibula ; SO, Branch of popliteal aiiiery, 12 THE MODKL MANIKIN PHYSIOLOGY No. XX. — Principal nerves and bloodvessels of left arm. 74, Left subclavian artery and vein ; 75 to 76, Brachial plexus of nerves ; 77, Ulnar nerve ; 78, Musculo cutaneous nerve ; a. Deltoid muscle ; b, Biceps muscle cut off ; c, Pronator teres. No. XXI. — Principal veins of left hand. No. XXII.— Anterior view of nerves of left leg and foot. , 1, Anterior crural nerve ; 2, Crural branch ; 3, Middle cu- taneous nerve ; 4, Internal cutaneous n. ; 5, Anterior division of obturator n. ; 6, Anterior tibial n. ; 7, Musculo cutaneous n. ; 8, Branch of anterior tibial n. ; 9, Extensor digitorum communis longus ; Extensor longus pollicis pedis ; 10, Rec- tus femoris muscle ; 11, Gastrocrtemius m. ; 12, Vastus in- ternus m.; 13, Sartorius m. cut off ; 14, Pecteneus m.; 15, Adductor longus cut oflE ; 16, Tibia os ; 17, Anterior annular ligament ; 18, 19, Muscles cut off ; 30, Internal saphenous nerve; 21, Femoral artery and vein ; 22, Vastus externus muscle ; 23, Patella. No. XXIII. — Inebriate's brain with enlarged bloodvessels. No. XXIV. — Alimentary canal with organs separated. 1, (Esophagus ; 2, Stomach ; 3, Pyloric orifice ; 4, Duodenum or second stomach ; 5, Liver ;'6, Spleen ; 7, 8, Jejunum and ileum or small intestines ; 9, CoeUo valve ; 10,' Coscum ; 11, Vermiform appendix ; 12, Ascending colon ; 13, Transverse colon ; 14, Descending colon ; 15, Rectum. No. XXV. — Diagram of circidation of blood. 1, Heart ; 2, Arch of aorta ; 3, Descending aorta ; 4, Ascend- ing aorta ; 5, Periphery in the head and upper extremities ; 6, Periphery in the lower extremities ; 7, Ascending vena cava; 8, Descending vena cava; 9, Ccelic axis artery— Gastric, hepatic, splenic ; 10, Mesenteric arteries ; 11, Renal arteries ; 12, Renal veins ; 13, Stomach ; 14, Spleen ; 15, Intestines ; 16, Kidneys ; 17, Liver ; 18, Portal vein and branches, includ- ing mesenteric, gastric and splenic veins ; 19, Lungs, INDEX 13 No. XXVI. — Confirmed inebriate's ulcerated stomach. No. XXVII.— Condition of stomach after death by delirium tre- mens. No. XXVIII. — ^Illustration of capillary circulation. No. XXIX. — Blood corpuscles. No. XXX.— Villi of intestines. No. XXXI.— Salivary glands. 1, Parotid gland ; 2, duct of same ; 3, Submaxillary gland ; 4, Sublingual gland ; 5, Carotid artery ; 6, External jugular vein ; 7, Tongue ; 8, Section of inferior maxillary bone. No., XXXII. — ^Vertical section of heart showing ventricles. 1, Right auricle ; 2, Bight auricular appendix ; 3, Superior vena cava ; 4, Infejior vena cava ; 5, Left auricle ; 6, iieft auricular appendix ; 7, Pulmonary veins ; 8, Pulmonary artery ; 9, Ascending aorta ; 10, Opening of pulmonary artery ; 11, Tricuspid valve — right auricular ventricular ; 13, Bicuspid valve — left auricular ventricular ; 13, Opening of aorta ; 14, Internal structure of left ventricle ;"15, Internal structure of right ventricle. No. XXXIII. — Lateral section through face and throat. 1, Nasal passages ; 3, Opening of eustachian tube ; 3, Tongue; 4, Section of inferior maxillary bone ; 5, Section of spine ; 6, Pharynx ; 7, Epiglottis ; 8, Interior of larynx ; 9, Hard palate ; 10, Mucus membrane beneath the tongue ; 11, An- 'terior portion of larynx. No. XXXIV.— Under side of Uver. 1, Bight lobe ; 3, Left lobe ; 3, Gall bladder ; 4, Lobulus quad- ratus ; 5, Lobulus spegelii ; 6, Inferior vena cava ; 7, Um- bilical vein ; 8, Hepatic artery ; 9, Hepatic duct; 10, Portal vein. No. XXXV. — Posterior view of small intestines with mesentery glands and bloodvessels &nd recepticulvun chili. No. XXXVI.— External posterior muscles of leg. 1, Glutseus maximus muscle ; 3, Glutseus medius ; 3, Semi- tendinosus m. ; 4, Biceps ; 5, Vastus extemus ; 6, Semi- 14 TflE MODEL MANIKIN PHYSIOLOGT membranosus ; 7, Internal head of gastrocnemius m. ; 8, External head of gastrocnemius i^.; &, 10, Gastrocnemius m.; 1], Soleus m.; 12, 13, Tendo achilles. No. XXXVII. — Posterior view of leg with external muscles re- moved to show the course of main arteries. 1, Popliteal artery with vena comites; 3, Anterior tibial artery and veins ; 3, Posterior tibial artery and veins ; 4, Peroneal artery and veins ; 5, Vastus externus m. ; 6, Semi- membranosus m.; 7. Termination of the femoral artery where it becomes the popliteal artery ; ,8, 9, Heads of gas- trocnemius m. ; 10, Fleior digitorum longus m. ; 11, Tendo achUles. No. XXXVIII. — Lateral viewof skull and anterior view of cervi- cal vertebra and thorax. 1, Frontal bone ; 3, Parietal b.; 3, Temporal b.; 4, Great wing of sphenoid b.; 5, Maler b.; 6, Superior maxillary b. ; 7, Nasal b. ; 8, Inferior maxUlary b. ; 9, Zygomatic arch ; 10, Maetus auditorius externus ; a. Occipital b. ; 11 to 17, Cer- vical vertebra ; 19, Section of clavicle b. ; 30 to 30, inclusive, ribs ; 31, Manubrium — first bone of sternum ; 33, Body or middle bone of sternum ; 33, Ensiform process, or lower end of sternum. No. XXXIX. — Lateral view of convolutions of brain and cavity of mouth. 1, Frontal lobe; 3, Parietal lobe; 3, Occipital lobe; 4, Tem- poral lobe ; 5, Supra marginal lobe ; 6, Cerebellum ; 7, Fissure of Silvius; 8, Fissure of Rolando; 9, Parieto-occipital fissure ; 10, Ganglion of the fifth nerve ; 11, Nerves to the teeth from the fifth nerve ; 13, Section of inferior maxiUary bone ; 13, Spinal column. No. XL.— Base of brain, with roots of cr&nial nerves and arteries. 1, Olfactory bulb; 2, Optis thalamus; 3 to 9, inclusive. Cranial nerves; A, Corpus callosum; B, Fissure of Silvius ; C, Cerebellum ; D, MeduUa Oblongata ; E, Anterior lobe of brain ; F, Middle lobe of brain ; G, Occipital lobe of brain, the right cerebellum having been removed, a, Anterior cerebral arteries ; b, Middle cerebral arteries ; c, Basilar arteries; d, Posterior cerebral art.; e, Vertebral art. No. XLI. — Lateral section through middle of brain with cranial nerves. 1, Fissure of Rolando; 2, Calloso-marginal fissure ; 3, Parieto- occipital fissure ; 4, Corpus callosum ; 5, Cerebellum ; 6, Ventricle; 7, Cms cerebri; 8, Pons varolii; 9, Medulla oblongata; 10, Eyeball; 11, Olfactory nerve; 12, Optic nerve ; 13, Fourth n.; 14, Fifth n.; 15, Sixth n.; 16, Seventh n.; 17, Eighth n.; 18, Ninth n.; 19, Tongue. No. XLII. — Anterior view of spinal column with spinal nerves proceeding from left side, and lymphatics on the right side, an- terior portions of the ribs being removed. a, GangUa of the sympathetic nerve ; b, Lymphatic glands and vessels ; c. Vertebra of spinal column ; d, Posterior portion of ribs ; e, Transverse spinous processes ; f , Clavicle; g. Scapula ; 29, Termination of the spinal cord within the first lumbar vertebra, and roots of lumbar and sacral nerves ; 30, Lumbar plexus nerves ; 31, Sacral plexus n.; 32, Ingm- cutaneous n.; 33, Anterior crural n.; 34, Ischiadicus, or Great Sciatic n. ; 35, Obturator n. No. XLIII.— The Pelvis:— k, Sacrum. 1, Sacral foramen; m, Obturator foramen; n. Ischium; o. Crest of ilium; p, Ilio-pubal-eminence; q, Sympnysis pubes; i-, Head of femur. No. XLIV. — Bones and lymphatics of right arm. h. Humerus; i, Radius'; j. Ulna; k, Lymphatic glands. No. XLV. — Bones of right hand. A Carpus:— 1 to 8, B, Metacarpus— 9 and 13; C— 10, 11, 12, 14 and 15,. Phalanges. No. XL VI. — Bones and lymphatics of right leg and foot. b, Lymphatic glands; S, Femur; t. Patella; u. Tibia; v. Fibula; w, Tarsus — seven bones; x, Metatarsus — five bones; y, z. Phalanges; — two in the great toe and three in each of the others. 16 THE MODEL MAMiEiN PHYSIOL06Y No. XLVII. — Bones and nervcB of left arm. 20, Cervical plexus nerves; 31, Brachial plexus n. 33, Median n. 23, Ulnar n. 34, Musculo-cutaneous n. 36, superficial radial n. ; 37, 38, Origin of spinal n. No. XL VIII. — Bones and nerves of left hand. 1, Branch of median nerve, sending branches to first three fingers; 3, Branch distributing to index finger and thumb; 3, Branch of ulnar n. distributing to ring and little fingers; a. Bones of the carpus; b. Bones of the metacarpus; c, d, e, Phalanges. No. XLIX. — Bones and nerves of left leg and foot. 34, Great sciatic nerve; 35, Obturator n. 36, External popliteal or peroneal n. 37, Peroneal profundus n. 38, Anterior tibial n. 39, Musculo-cutaneous n. 40, Internal peroneal profundus n. 41, External peroneal profundus n. 43, Branch of anterior tibial n. Bones, see div. XLYI. No. L. — Posterior view of skull, spinal column and ribs. 1, skull; 3, seven cervical vertebra; 3, twelve dorsal vertebra; 4, Five lumbar vertebra ; 5, The sacrum, five vertebra; 6, Ilium; 7, Scapula; 8, Femur; 9, Cocyx. No. LI. — An elaborate view of the Great Sympathetic nerve, with all its detailed distribution. 1, Medulla oblongata; 3, Pneumogastric nerve; 3, Branch of same'to lung; 4, Cardiac plexus of same; 5, Cervical plexus nerves; 6, Brachial plexus; 7, Semi-lunar ganglion; 8, 9, Lumbo-aoftic plexus; 10, Hypogastric plexus; 11 — 11, Inter- costal nerves and bloodvessels; 13, Lumbar nerves; 13, Sacral plexus; a. Chain of great sympathetic ganglia: A, Thyroid gland; B, Aorta; C, Heart; D, Right auricle; E, Trachea with bronchial tubes cut o£E at their origin; P, Pneumogastric plexus following the course of the CEsopha- gus and distributing branches to the stomach and intes- tines. G, Descending Aorta ; H, Intercostal veins and arteries; I, Stomach; J, Pyloric end of stomach; K, Trans- verse colon; L, Small intestines, M, N, Rectum; O, Inferior Vena Cava; P, Primitive Iliac artery; R, Iliac vein; S, Lung; INDEX 17 T, section of ileum: U, Section of Symphysis pubes. For nerves of the head, see Div. XLI. No. Lll. — Small section of spinal cord showing the origin of a spinal nerve. 1, internal gray substance of cord ; 3, Posterior root of nerve ; 3, anterior root of nerve ; 4, Union of the two roots in one sheath. No. LIII. — Section of inferior maxillary bone of an infant, show- ing undeveloped teeth. 1, 1, First developed teeth ; 2, 3, second teeth undeveloped; 3, wisdom tooth. No. LIV. — A vein laid open, showing its valves. No. LV. — Arch of aorta ruptured by disease. No. LVI. — ^The Csecimi and lower portion of ascending colon laid open. 1, Termination of ileum; 3, Appendix vermiformis; 3, Ileo- csecal valve; 4, opening of appendix vermiformis. No. LVII. — Section of small intestines laid open, showing ulcera- tion. No. LVIII. — Posterior view of left leg, external muscles having been removed to show the Great Sciatic nerve and its branches, 1, Great Sciatic nerve; 2,3, Internal popliteal and posterioi tibial nerves; 4, Posterior femoral cutaneous n.; 5, Mus- cular n. ; 6, Communicans flbularis n. ; 7, Short head ol the biceps muscle; 8, Long head of the biceps muscle; 9, Integument. No. LIX.— Section of head of femur, showing texture of bone. No. LX. — Ligaments of elbow. No. LXI. — Ligaments of vsrrist. No. LXII. — Ligaments of shoulder. No. LXIII. — Ligaments of hip. No. LXIV. — Ligaments of ankle. No. LXV. — Ligaments of knee. No. LXVI. — Lateral view of section through the middle of th6 foot, showing the form and relations of the bones. 18 THE MODEL MANIKIN PHYSIOLOGY 1, lower end of tibia; 3, Astragalus; 3, Os calcis; 4, The scaph- oides; 5, The Cuneiforme internum; 6, Metatarsal bone of great toe; 7, First phalanx of great toe; 8, second phalanx of greattoe; 9, Tendon Achilles. No. LXVII.— "Vertical section of bone magnified, showing texture and arteries. No. LXVIII. — Anterior view of the eye. 1, The pupil; 2, The Iris; 3, Sclerotic coating ; 4, Upper eye- lid; 5, Eyebrow. No. LXIX. — Anterior view of glands and ducts of the eye. 1, Lachrymal gl'and and ducts; 3, Upper eyelid; 3, Apertures of ducts; 4, Canaliculi; 5, Pupil; 6, Iris; 7, Puncta Lachry- malia; 8, Lachrymal sack and nasal duct. No. LXX. — Anterior view of eye-ball, the lids being removed: — 1, Pupil; 3, Iris; 3, Sclerotic coating with bloodvessels; 4, Superior rectus m.; 5, External rectus m.; 6, Inferior rectus m. ; 7, Internal rectus m. No. LXXI. — Eye-ball, with nerves and muscles as seen from above: — 1, Superior rectus muscles; 8, External rectus m. 3, Superior oblique and internal rectus muscles; 4,5, eye-baU; 6, Lachry- mal gland. No. LXXII. — Transverse vertical section through middle of eye, showing lenses, coatings and muscles: — 1, Vitreous humor; 3, Crystalline lens ; 3, Ciliary body; 4 Pupil; 5, Cornea; 6, Optic nerve; 7, Levator palpebrse supe- rior m. 8, Palpebra inferior; 9, Retina; 10, Hyaloid mem- brane; 11, Sclerotic coat; Choroid membrane between 10 and 11; 13, Tendons of rectus m. 18, 13, 13, Rectus oculi superior; Rectus oculi inferior and Levator palpebrse supe- rior muscles. No. LXXIII.— External ear. No. LXXIV. — ^Greatly magnified bony labyrinth of ear. 1, Superior semi-circular canal; 2, Inferior semi-circular canal; 3, External semi-circular canal: 4, Body of the incus; 5, Mai- INDEX 18l leus; 6, Ampulla on external semi-circular canal; 5, First turn of cochlea; 8, The cupola; 9, Ampullss on No. 3; 10, Ampullae on No. 2. No. LXXV. — External and internal ear. 1, The opening in the ear; 2, Msetus auditorius externns; 3, The tympanum; 4, Eustachian tube; 5, 6, 7, Labyrinth. No. LXXVI.— Tongue and throat. 1, superior surface of tongue; 2, Uvula; 3, Labium superius; 4, Nostrils. No. LXXVII. — Same as LXXVI. with epithelial cancer. No. LXXVIII.— Tongue and tonsils. A, Ligament and mucus membrane from root of tongue to epiglottis; b, Tonsils. No. LXXIX. — A molar tooth — lateral view. 2, Crown; 3, 3, Fangs or roots. No. LXXX. — Section of molar tooth. 1, Crown; 2, 2, Ivory; 3, Pulp in its cavity; 4, 4, Nerves, arte- ries and veins. No. LXXXI. — Section of bicuspid tooth. 1, Ivory; 2, Enamel, worn from the summit of the crown; 3, Pulp in its cavity. No. LXXXIL— Section of skin. a, Epidermis or cuticle; b, Stratimi corneum; c, Derma or true skin; d, Hair follicles and sebaceous glands; e, sweat glands; f , f , glands. No. LXXXIII. — Larynx — anterior view. 1, Corpus ossis hoidei; 2, Corno majus ossis hoidei; 3, Thyro- hyoideima lateral ligament; 4, Thyro-hyoideimi medium ligament; 5, Ligaments; 6, Thyroid cartilage; 7, Pomum adami; 8, Crico-thyroideum medium ligament; 9, Cricoid cartilage; 10, Annulus cartilage of tracheae; 11, Lateral crico-thyroideum ligament. No. LXXXIV.— "Vertical section of larynx, showing internal struc- ture: — lower figure: — 20 THE MODEL MAKlklU PHYSIOLOGY 1, Posterior surface of epiglottis; 3, Os hyoideum; 3, thyroid cartilage; 4, Cricoid cartilage; 5, Lower vocal cord; 6, Ven- triculus larynges; 7, Upper vocal cord. Upper figure: — vocal cords seen from above. No. LXXXV.— Lateral external view of Larynx, with its muscles. 1, Epiglottis; 2, Thyroid cartilage; 3, Cricoid cartilage; 4, Trachea with rings of cartilage; 5, Arytoenoid cartilage; 6, Hyo-epiglottic membrane; 7, Crico-thyroid muscle; 8, Poste- rior Crico-arytenoid muscle; 9, Lateral crico-arytenoid muscle; 10, Fibres of No. 9; 11, Thyro-epiglottic muscle; 13, Superior thyro-arytenoid muscle; 13, Transverse thyro- arytenoid muscle; 14, Thyro-arytenoid muscle; 15, ary- epigloticus muscle. No. LXXXVI. — Anterior view of stomach. 1, Cardiac orifice, opening into (Esophagus; 3, Cardiac end; 3, Pyloric end. No. LXXXVII. — Internal view, of healthy stomach. 1, Mucus membrane and rugae; 3, Pyloric orifice; 3, Duode- num; 4, Gall Bladder; 5, Hepatic duct; 6, Pancreatic duct; 7, Opening to (Esophagus. No. LXXXVIII. — Transverse horizontal section of thorax. 1, Heart; 3, Left lung; 3, Eight lung; 4, Aorta cut off; 5, Main pulmonary artery; 6, Eight pulmonary artery; '?, Left pulmonary artery; 8, Descending vena cava cut ofE; 9, Descending Aorta; 10, Bronchial tubes; 11, (Esophagus; 13, Dorsal vertebra; 13, Vena Azygos; 14, Pulmonary veins; 15, Sternum. No. LXXXIX. — Anterior view of heart: — 1, Ascending Aorta; 2, Pulmonary artery; 3, Eight auricular appendix; 4, Left auricular appendix; 5, Eight coronary artery; 6, Great coronary vein; 7, Apex of heart; 8, Peri- cardium thrown back. No. XC— Diagrammatic section of heart, with parts separated: — 1, Descending vena caya; 2, ascending vena cava; 3, Eight auricle; 4, Eight ventricle; 5, Eight and left pulmonary INDEX 21 artery; 6, Pulmonary veins; 7, Left auricle; 8, Left ven- tricle; 9, Ascending aorta; 10, Arch of Aorta; 11, Descending aorta. No. XCI. — Transverse horizontal section through the heart: — 1, Tricuspid valves; 2, Bicuspid valves; 3, Semi-lunar valves of aorta; 4, semi-lunar valves of pulmonary artery. No. XCII. — Muscles and tendons of outside of foot. 1, Amiulat ligament; 2, Extensor digitorum communis longUs; 3, Peronseus tertius v. parvus; 4, Abductor digitii minimi; 5, Extensor digitorum communis brevis ; 6, Same as 4, being part of it. No. XCIII.— External kidney:— 1, Benal duct or ureter; 2, 3, Eenal artery and vein. No. XCIV. — Internal structirre of Iiidney. 1, Cortical concretions or secreting surface; 3, Pyramids mal- phighi; v. coni tubulosi; 3, Papilla renalis or mammUlary process; 4, Calyx renalis; 5, Eenal pelvis; 6, Ureter; 7, Benal artery; 8, Renal vein. No. XCV. — Fatty degeneration of kidney. No. XCVI. — Arteries of the sole of the foot: — 1, 1, Tendons of the flexor communis and flexor longus polli- cis pedis m. 3, Arterial branch to anastomose with the pos- terior tibial; 3, Peroneal artery; 4, Posterior tibial artery at the ankle; 5, 5, External and internal plantar arteries. No. XCVII. — Muscles and tendons of sole of foot: — 1, Os caJcis; 3, section of fascia plantaris; 3, Abductor policis, muscle; 4, Abductor minimi digiti m. 5, Flexor brevis dig- itorum m. 6, Tendon of the flexor longus pollicis m. 7, Lumbricales m. No. XCVIII. — Muscles and tendons of inside of foot: — 1, Internal maleolus;. 3, Anterior tibial tendon; 3, Adductor policis pedis m. 4, Tendo extensoris poUicis pedis longi. No. XCIXl — Arteries and tendons of back of the hand. 33 THE MODEL MANIKIN PHYSIOLOGY INDEX No. C. — Closed hand — outside. 1, Anterior annular ligament of wrist; 3, 3, 4, Muscular mass of thumb and palm. No. CI. — ^Arteries of back of the hand, the tendons being removed. ' No. CII. — Closed hand — inside view. 1, Extensor carpi radialis longus; 3, Extensor primi internodii pollicis; 3, Extensor ossis metacarpi pollicis; 4, Extensor I secundi internodii pollicis; 5, Extensor indicis; 6, Extensor carpi radialis brevis; 7, Abductor indicis; 8, Abductor poll- icis. A COMPEND OF ANATOMY AND PHYSIOLOGY. HUMAN ANATOMY AND PHYSIOLOGY. The study of the human body naturally divides itself into two general departments. The first, called Anatomy, treats of the structure of the body and the relation of its various parts to each other and to the whole; and the second, called Physiology, which treats of the functions or uses of the organs. _ For convenience of study the manikin has been so con- structed and arranged that the structure and functions of the entire body may be considered under five general di- visions, as follows : 1. Bones and Ligaments. 2. Muscles, Fascia, and Tendons. 3. The Alimentary Canal or Digestive Tract, with the Liver and Pancreas. 4. Organs of Eespiration and Circulation, including Heart, Lungs, Larynx, and Trachea, with the blood-vessels and lymphatics, and also the Kidneys and the Spleen, 1 24 ■ A COMPEND OF 5. The Brain and Nervous system, including the construc- tion and functions of the organs of the special senses. The Koman numerals in this manual refer to the. corre- spending parts of the manikin, and the common figures and small letters that follow t^iem, to the divisions or organs within the parts. Where the figures and small let- ters are not in immediate connection with Koman numer- als, the reference is to the part indicated by the Koman numerals next preceding. BONES. The bones constitute the framework of the body, and are the basis' of the entire physical structure, by which, also, the position and motions of the body are governed. They are composed mostly of certain forms of lime and gelatin, in about the proportion of one of gelatin to two of lime; but these proportions are different at different periods of life, the gelatin being in larger proportion in youth and the lime in old age. The gelatin gives tough- ness and elasticity, and the lime hardness and strength. On this account the bones of children are not so easily broken as those of persons in old age, the elastic cartilage yielding more readily to accidental pressure. If a bone be cast into the fire the gelatin will be con- sumed, but the lime will resist the action of the fire and preserve its original form, but can be crushed to powder by slight pressure; but if the bone be exposed to the ac- tion of certain powerful acids the lime will disappear, and there will be left only the gelatinous matter having the ANATOMY AND PHYSIOLOGY. 25 original form of the bone, but very flexible and easily bent in any direction, without breaking. Bone is a dense sub- fibrous basis filled with minute cells and traversed in all directions by inosculating canals terrned Haversian, which give passage to blood-vessels and nerves. These cells are irregular in form and give off numerous branching tubes, which, by various intercommunications, form a very deli- cate network. (LIX.., LXVII.) All bones are enveloped in a fibrous membrane called periosteum, a Greek term meaning around the bone. Where this membrane extends over cartilages, it is called perichondrium, and where it envelops the bones of the skull it is termed pericranium. The internal cavities of bones* are lined with a membrane termed medullary, and filled with a substance called medulla, or marrow. The movable joints and their ligaments are lined with a membrane (synovial), which secretes a lubricating fluid (synovia). The bones of the skeleton as generally enumerated, in- cluding the teeth, are two hundred and forty-six, as fol- lows: 8 Bones of the Cranium (XXXVIII., L.). Frontal one. Parietal two. Temporal two. Sphenoid one. Ethmoid one, and Occipital one. 14 bones of the Pace (XXXVIII.). Superior Maxillary two. Inferior Maxillary one. Malar two. Lachrymal two. Turbinated two. Nasal two. Vomer one, and Palate two. 24 bones of Spikal Columk (XXXVIII., XXXIX., XL., 26 A COMPENP of' L.). Cervical Vertebras seven, Dorsal Vertebrae twelve, and Lumbar Vertebrae, five. ' 4 bones of Pelvis (XLIII., L.). Innominata two, Sacrum one. Coccyx one. < 24 EiBS (XXXVIII., XLII., L.). True Eibs fourteen, False Eibs six. Floating Eibs four. 1 bone Os Hyoides (tongue bone). 1 STBEifUM (breast bone) (X., XXXVIII.). 4 bones of Shoulder (X., XXXVIII., XLII., L.). Clavi- cle (collar bone) two. Scapula (shoulder blade) two. 6 bones of Akm (XLIV., XLVIL). Humerus two. Ulna two, Eadius two. 16 bones of Wkist (carpal). ) 10 bones of Hand (metacarpal). [ (XLV., XLVIII.) 28 bones of Fingeks (phalanges). ) 8 hopes of Legs (XL VI., XLIX). Femur (thigh) two. Pa- tella (knee) two. Tibia two. Fibula two. 14 bones of Ankle (tarsal). ) 10 bones of Foot (metatarsal). V (XLVI., XLIX.) 28 bones of Toes (phalanges). ) 32 Teeth (XXXVIII., XXXIX.). Incisors eight. Canine four, Bicuspids eight, Molars twelve, 8 bones Sesamoid — average. Bones are classified as long, short, flat, and irregular, ac- cording as they are fitted for motion, support, or protec- tion, either alone or in any combinations of these qualities. The long bones are found in the limbs and constitute a system of levers for locomotion; and, while they are rela- tively small in the shaft or middle portion, which is dense ANATOMY. AND PHYSIOLOGY. 27 and compact for strength, they are more or less expanded and porous at the extremities, where they unite to form joints or articulations, and have numerous protuberances for the attachment of the muscular bands, by which mo- tion is effected. All the bones in the upper and lower ex- tremities with the clavicle, exce;^ the carpal and tarsal bones of the wrist and ankle and the patella of the knee- joint, are reckoned in this class. The short bones are the eight carpus in the wrist and the seven tarsus in the ankle. In each case these bones articulate and are bound together by ligaments in such a manner as to admit of the slight motion that is incident to their position. The flat bones are to be found where protection or broad muscular attachments are required, as in the skull and the scapula or shoulder-blade. These flat bones are gen- erally composed of two thin layers of compact tissue in- closing between them a variable quantity of cancellous tissue. In the cranial bones these layers ofcompact tissue are familiarly known as the tables of the skull; thfe outer one is thick and tough, the inner one thinner, denser, and more brittle; and hence termed the vitreous table. The intervening cancellous tissue is called the diploe. The flat bones are the occipital, parietal, frontal, nasal, lachry- mal, vomer, scapula, ossa innominata, sternum, ribs, and patella. The irregular bones are such as cannot properly be called long, short, or flat. They include the vertebrfe of the spinal column, including the sacrum and coccyx; the temporal, sphenoid, and ethmoid, in the skull, the supe- 28 A COMPEND OF rior and inferior maxillary and malar, and the inferior turbinated, palate, and hyoides. THE SKULL. (XXXVIIL) In descriptive anatomy, the bones of the skull are di- vided into The Cranium and The Face. The eight bones of the cranium and the bones of the face, except the infe- rior maxillary, articulate by a sort of irregular dovetail work, and these joints are called sutures. It is supposed that one of the uses of these is to permit the growth of the skull, as they are frequently nearly or quite obliterated •after the growth is complete as age advances. The coro- nal suture unites the frontal and parietal bones; the sagit- tal unites the two parietal bones, forming the longitudinal seam along; the top of the skull; the lambdoidal connects the occipital a»d parietal bones, and the squamous unites a portion of the temporal bone with the parietal and sphe- jioid. The spaces for the lodgment of the eyes and their ac- cessory muscles, vessels, nerves, and glands, are termed orbits. Each orbit has nine openings for the transmis- sion of these accessories. The nasal cavity is divided into three longitudinal pas- sages called meatuses (XV., 5). There are two sets of teeth, milk>teeth (infant), twenty in number, and permanent teeth, thirty-two in number. (XXXVIIL, XXXIX., LIIL) anatomv and physiology. 29 The milk teeth consist of eight incisors, four canine, and eight molars. The permanent teeth are thirty-two, sixteen in each jaw. Each half of each jaw proceeding from the middle con- tains two incisors, one canine, two bicuspids, and three molars. (LXXIX., LXXX., LXXXI.) The Infeeior Maxillary or lower jaw articulates by condyles with the glenoid cavities in the temporal" bones and are sustained in position so as to allow for its necessary motion, by the external lateral ligaments, the capsular ligament, fibrous cartilages, and synovial membranes. The FoEAMEN Magnum is a large oval aperture in the occipital bone in the base of the skull, for the passage of the medulla oblongata, spinal accessory nerves, and verte- bral arteries. THE SPINAL COLUMN. (XLIL) The general character of the vertebra composing this column may be stated thus : Each vertebra is less than an inch in its vertical measurement, and has an aperture through which the cord passes, called the vertebral fora- men, and another, on each side, called the foramen for the vertebral artery. Each has also an osseous posterior pro- jection called the spinous process, and a lateral process on each side, for the a"ttachment of various muscles. The bodies of the vertebrae are piled one upon the other, forming a strong pillar, for the support of the cranium and trunk ; the arches forming a hollow cylinder behind ■30 ,A COMfEND OF for the protection of the spinal cord. The different ver- tebrse are connected together by means of the articular processes and the intervertebral cartilages; while the transverse and spinous processes serve as levers for the attachment of muscles which move the different parts of the spine (c). The first Cervical Vertebra which articulates imme- diately with the skull in the vertebral foramen is called the atlas, and is so cons<;rncted as to form a pivotal joint with the second vertebra, called the axis, by which the head is moved in every direction. The twelve Dorsal Vertebrae are those to which the ribs are attached, and are provided with cavities for their attachment, called facets. The facet for the first rib is en- tirely in the first dorsal vertebra; from the second to the ninth inclusive the facets are partly in the vertebra above and partly in the one below the Junction; and for the ■tenth, eleventh, and twelfth ribs they are each entirely in the , corresponding vertebra. Between each articulating pair of vertebrje there is an orifice on each side for the passage of nerves throughout the entire length of the column. The five Lttmbar Vertebra form the connection be- tween the thorax and pelvis, and the five sacral vertebrae in the adult become a single bone called the Sacrum, and is one of the constituents of the pelvis. _ The Coccyx is the lower extremity of the Sacrum, and is composed of four segments of bone, thus completing the spinal column. The spinal canal does not pass through ' it, but terminates in the fifth sacral vertebra. ANATOMY AND PHYSIOLOGY. 3 1 THE PELVIS. (XLIII.) The Pelvis incloses the lower portion of the abdomi- nal cavity and supports the spinal column, resting on the two femurs. It is composed of the two bones called os innominatum at the sides and front, and the sacrum and coccyx behind (k). Each os innominatum is described in three divisions: the ilium or upper part (o), the ischium or extreme lower part (n), and the ptibes in front (q). The acetabulum is the cavity external to the pubes, by which, in conjunction with the femur or thigh bone, the hip joint is formed (r). The large space inclosed by the pelvis, through which the great sciatic nerves pass to the lower extremities, is called the sacral foramen (1). The openings bounded by the pubes above and the ischium below are the passages for the obturator nerves and blood-vessels, and are called obturator foramen (m). THE THOEAX. (XXXVIII.) The Thoeax is the bony framework inclosing the organs that control respiration and the circulation of the blood. It is formed of the twelve dorsal vertebrae on the back, of the twelve ribs on each side, and of the sternum or breast bone and the costal cartilages in front. The ribs are at- tached to the vertebrae by ligaments and cartilage in such manner as to* hold them firmly in position, while there is 32 A COMPEND OF all the freedom required for their slight motions in breath- ing. The sternum in front is composed of three pieces, the upper one called the manubrium (31), to which the first ribs are attached by cartilage, the middle one called the gladiolus (33), to which five ribs, from the third to the seventh, on each side are attached, by cartilage, and the lower extremity called the ensiform appendix (33). The second rib on each side articulates at the junction of the manubrium and gladiolus. The eighth, ninth, and tenth ribs attach .theniselves by cartilage with each other and the seventh rib. The eleventh and twelfth ribs are free, having no attachment except to their vertebrse. The costal cartilages allow of the freedom of action of the ribs required in breathing. THE CLAVICLE AND SCAPULA. The Clavicle (XXXVIII., 19, XLII., f), or collar bone, is a long bone which articulates with the upper part of the sternum and extends horizontally over the first rib to unite with the scapula in articulation with the humerus to form the shoulder joint. The Scapula (XLII., g, L., 7) forms the back part of the shoulder. It is a large, flat bone, triangular in shape,' situated at the posterior aspect and side of the thorax, be- tween the first and eighth ribs, its posterior border or base being about an inch from and nearly parallel with the spinous processes of the vertebras. Tbe joint is formed by the articulation of the head of. the HuMEEUS (XLIV., h) with the glenoid "cavity in the ANATOMY AND PHYSIOLOGY. 33 scapula; and the external extremity of the clavicle artieu- ' lates with the large and somewhat triangular process of the scapula, which overhangs the glenoid cavity. BONES OF THE AEM. (XLIV.) The Humerus (h) is the longest and largest hone of the arm; it presents a shaft and two extremities. The upper extremity or head is nearly hemispherical in form; its sur- face is smooth and is coated with cartilage, and articulates with the glenoid cavity of the scapula. The shaft is almost cylindrical in the upper half of its extent, hut prismatic andflattened helow. The lower extremity expands laterally into two processes, called the internal and external con- dyles, between which are the trochlea and rotula, by which articulation is formed with the Eadius (i) and Ulna (j) in the forearm to form the elbow Joint. These latter are so arranged side by side and so connected at the elbow at one extremity, and with the bones of the wrist at the other, that every necessary motion of the hand and arm may be easily performed. The wisdom of this arrangement is most apparent. BONES OF THE WEIST AND HAND. (XLV.) The eight bones of the wrist are called The Carpus (A, 1 to 8), and are arranged in two rows; the upper row counting from the radial to the ulnar side are the scaphoid. 34' , A COMKEJfD OF s, semilunar, crnieiform, and pisifo^'m; those of the lower, ill the same manner are the trapezium, trapezoid, Os ma'g- nunia and unciform. TJie scaphoid and semilunar articulate •^itlit^e Radius, while the other bolie of the forearm— the 'ulna— is attached to the wrist joint by a small articulation with the radius and a simple fibro-carfeilage, and does not articulate .with any of the bones of the carpus. This/ ar- rangement is in paiit a provision for the revolving motion • of tiie forearm. The first five bones of the hand articulating with the. four lower bpnes of the carpus are called The Metacar- pus (B,9and 13). .Articulating with the lower heads of these and -wiih each other to form the thumb and' fingers, are the -two additional bones of the thijjnb, and the three ad'difional bones of each of the four fingers comprising the fourteen PsALANGES (C, 10, 11, 12, 14, -15). . ■''■"[ ' BONES OF THE LEG. ';. '. • , ■' (XLVI). , The Femur or thigh bone (S) is the longest, largest, and strongest bone in the skeleton, and almost perfectly i - cylindrical in the greater part of its extijit. In the- erect posture it is not vertical, being separa^^ from its; fellow-' above by a considerable interval, which corresponds ;to the i^ .entire breadth of the pelvis, but inclining gradually down- ward and inward, so as to approach itfe fellow toward it;s lower part, for the purpose of bringing the knee joint near the line of gravity of the body. The degree of this incli- nation varies in different persons, aad is* greater in the ANATOMY AND PHYSIOLOGV. " -35 female than in the male, on account of the greater breadtii of the pelvis. The femur, lik« other long" bones, is divisi- ble into a shaft and two extremities. The upper ^trein- ity presents a head, a neck, and the-greater and Msser tro- chanters. ■ • ■ /., ' The; Hip Joint is a ball and socket, the head of . the femur b.eing spherical and mctving in a cavity in the pelvis .called- acetabulum. The portion below the head is Smaller, and isgealled the neck. Sometimes this portion, by reason* of itsi|relative weakness, is fractured, and in such^^ cas6 re- covery is very slow, and in aged persons, frfequently, they^ remain permanent cripples. Below the* neck the bone Is much -larger, presenting an external prominence called the great trochanter,' and an internal one called the lesse* tro- chanter. ^^yhe shaft' of the femur is a cylinder of comjpact tissue, with a l|.rge medullary canal. It is of great thickness and density .in the middle third of the shaft, where the bone is;|iarrowest and the medullary canal well formed j hut, above 'and below this, the cylinder gradually becomes thin- . ner. Owing to a separation of the layers of the bone into oancel]i,whi>• The''PateI/LA (t) is a small, flat bone covering the front 36 A COMPEND OF of the knee joint, the importance of which will be under- stood when we treat of the muscles connected with it. The Tibia (u) and Fibula (v) are the two bones of the leg below the knee. The tibia is on the inner side, and is large and strong for the support of the body, while the fibula is very slender in proportion to its length. The tibia expands at its head to correspond with the condyles and notch of the femur with which it articulates. The fibula does not ascend to the condyles of the femur, but articulates with the tibia just below its superior enlarge- ment. The middle portion of the shaft of the tibia is relatjively small, but compact; while the shaft of the fibula is of nearly equal thickness through its entire length. These two bones are united at their lower extremities, and together form an articulating surface, by which they are attached to the astragalus of the ankle joint. The connec- tion of these bones at their enlarged extremities leaves considerable space between their shafts through which nerves and blood-vessels pass. THE TAESUS. (XLVI., w w.) The Taesus consists of seven bones, viz.: the calca- neum or os calcis, astragalus, cuboid, scaphoid, internal, middle, and external cuneiform bones. The Calcaneum (os oalcis) (LXVI., 3) is the largest and strongest of the tarsal bones, situated at the lower and back part of the foot, serving to transmit the weight of ANATOMY AND PHYSIOLOGY. 37 the body to the ground, and forming a strong lever for the muscles of the calf. The Cuboid is placed on the outer side of the foot in front of the os calcis, and behind the fourth and fifth metatarsal bones. The AsTEAGALtJS (LXVI., 2) is the largest of the tar- sal bones next to the os calcis. It occupies the middle and upper part of the tarsus, supporting the tibia above, articulating with the maleoli on either side, resting below upon the os calcis, and joined in front to the scaphoid. The Scaphoid (LXVI., 4) is situated at the inner side of the tarsus, between the astragalus behind and the three cuneiform bones in front. The Internal Cuneiform (LXVI., 5) is the largest of the three, and is situated at the inner side of the foot, between the scaphoid behind and the base of the first me- tatarsal in front. The Middle Cuneij'oem, the smallest of the three, is situated between the other two bones of the same name, and corresponds to the scaphoid ( behind, and the second metatarsal in front. TsE External Cuneiform occupies the centre of the front row of the tarsus, between the middle cuneiform in- ternally, the cuboid 'externally, the scaphoid behind, and the third metatarsal in front. Thus it is apparent that the lower row of tarsal bones are in order as follows, counting from the inside outward : Internal Cuneiform, Middle Cuneiform, External Cunei- form, and Cuboid. The Metatarsus (x x x), consisting of the first five 38 A' COMPEND OF bones of the foot, articulate with the four above men- tioned. Phalanges (y, z). As with the hand, so with the foot, there are fourteen phalanges attached to the metatarsus — two in the great toe and three each in the other four toes. LIGAMENTS. The skeleton in the manikin exhibits the joints without the ligaments, but their nature and uses are illustrated separately. The bones at all their joints or articulations are bound together by these strong, tough, flexible, fibrous bands, which are so disposed as to bind the parts closely together, so as to prevent easy dislocation, and at the same time to permit all the natural movements required. Any violent and improper straining of these bands which tends to dislocate a joint is called a sprain, and is usually slow of recovery. The vertebrae of the spinal column are bound together by combinations of these bands, some of which extend over its entire length. The ribs' also, by the same means, are adjusted, at their anterior and posterior extrem- ities, to the vertebrae and the sternum. At all the joints where there is variety of motion, these bands are variously crossed and lapped and interlaced with each other, as nec- essary to sustain the bones in their normal position. Tbey are firmly attached by incorporation with the periosteum. The following are illustrations of their general character : LX., Ligaments of elbow; LXI., Ligaments of wrist; LXIL, ..Ligaments of shoulder; LXIIL, Ligaments of hip; LXIV., Ligaments of ankle; LXV., Ligaments of knee. ANATOMY AND PHYSIOLOGY. 39 There are certain ligaments also whose function seems to be to prevent the displacement of certain muscles, tendons, and blood-vessels beneath them by muscular action. Of these may be noted : The Anterior Annular Ligament of the wrist (C, 1), which sustains the muscles and tendons of the hand and forearm in proper position; the Anterior Annular Liga- ment of the ankle (XXII., 17), which effects the same re- sult in its position; and Poupart's Ligament (II., 26), ex- tending frpm the anterior superior spine of the ilium to the spine of thepubes. The femoral artery and vein' com- mence immediately behind the middle portion of this liga- ment. MUSCLES, TENDONS, FASCIAE, APONEUEOSES. The Muscles are connected with the bones, cartilages, ligaments, and skin, either directly or through the inter- vention of fibrous structures, called tendons or aponeuro- ses. Where a muscle is attached to bone or cartilage, the fibres terminate in blunt extremities upon the periosteum or perichondrium, and do not come in direct relation with the osseous or cartilaginous tissue. Where muscles are connected with the skin they either lie as a flattened layer beneath -it, or are connected with its areolar tissue by larger or sinaller bundles of fibres, as in the muscles of the face. The muscles vary extremely in their form. In the limbs they are of considerable length, especially the more super- ficial ones, the deep ones being generally broad; they snr- 40 A COMPEND OF round the bones and form an important protection to the various joints. In the trunk they are broad, flattened, and expanded, forming the parietes of the cavities which they inclose; hence the reason of the terms, long, broad, short, etc., used in the description of a muscle. Tendons are white, glistening fibrous cords, varying in length and thickness, sometimes round, sometimes flat- tened, of considerable strength, and only slightly elastic. They are the cords by which certain muscles are attached to the bones. The FASCiiE are fibro-areolar or aponeurotic laminae, of variable thickness and strength, found in all regions of the body, investing the softer and niore delicate organs. Aponeuroses are fibroas membranes of a pearly -white color, iridescent, glistening, and similar in structure to the tendons. The tendons, aponeuroses, and fasciae in general are the appendages of the muscles, for protection, aid, and attach- ment in the performance of their functions. The Muscles are the fleshy portions of the body, and are the organs which, by contraction and relaxation, pro- duce all its motion. They are composed of bundles of fibrous tissue, inclosed in cellular sheaths. Voluntary muscles act under the direction of the will; involuntary muscles act independent of the will. The latter control the functions of the vital organs within the body. In the limbs it is necessary that there be muscles for bending the organs in opposite directions ; hence some are cEjiJled flexors, and others extensors, on the opposite ; sides. ' . . , . . ANATOMY AND PHYSIOLOGY. 4I As the mtiscles and tendons constitute the bands by which movements of the skeleton are effected, it is import- ant in their study not only to refer to those parts of the manikin representing the muscles, but also to those repre- senting the skeleton. MUSCLES OF THE HEAD, PACE, AND NECK. (I.) The OcciPlTO-FEONTALis covers the front, top, and back of the head, from the eyebrows to the occiput. The frontal portion (1) raises the eyebrows and wrinkles the forehead. The Orbicularis Palpebrarum (6, 6), with the aid of the corrugator supercilii, and the tensor tarsi, which it con- ceals, closes the eyelids and draws the eyebrows downward and inward. Levator labii superioris almque nasi (7) raises the upper lip and expands the opening of the nose. Zygomatic major (9) and Zygomatic minor (8) pull the corner of the mouth upward and outward. Orbicularis oris (10) surrounds the mouth and closes and contracts the lips. Depressor labii inferioris (11) raises and protrudes the chin. Masseter (12), with tlie Temporal and Internal Pterygoid, closes the jaws and performs the bruising motion in chewing. The Buccinator circumscribes the cavity of the mouth and shortens the cavity of the pharynx in swallowing. 42 A COMPEND OF Platysma myoides (18) draws the angle of the mouth, depresses the lower jaw, and produces traction on the in- teguments of the neck. SternocUido- Mastoid (13) co-operates with the above in bending the head forward ; either one acting singly draws , the head toward the shoulder and carries the face to the opposite side. It extends from the mastoid process to the superior extremity of the sternum. Trapezius (16, 17). The upper fibres draw the shoulder upward and backward, the middle directly backward, and the lower downward and backward. It is attached to the spinal column from the occipital bone to the 13th dorsal vertebra, and its fibres from this line converge to the a,cromion and the spine of the scapula. Levator anguli scapulm (15) lifts the upper angle of the scapula and aids to carry the shoulder upward and back-' ward. The Splenius (14) of one side draws the vertebral col-- umn back and to one side, and the two acting together draw the head forward. Ai^TTEEIOE MUSCLES ON THE EIGHT SIDE OF THE BODY. (II.) . ' Platysma myoides (19) (see I., 18). Pectoralis major (30), with pectoralis minor, which it coveiB, draws the arms toward the chest. Deltoid (31) raises the arms at the shoulder joint. ANATOMY AND PHYSIOLOGY. 43 Serratus Magnus (22) is attached in front to the eight upper ribs, and behind is inserted into the margin of the posterior border of the scapula. Its action involves most of the motions of the shoulder and the ribs. External oblique (23, ^4) is sitiiated on the side and front of the abdomen, being the largest and most superfi- cial of the three flat muscles in this region. It arises by- eight fleshy digitations from the external surface and lower borders of the eight inferior ribs. Some of its fibres, pass nearly vertically downward, to be inserted into the anterior half of the outer lip of the crest of the ilium;' the middle and upper fibres, directed downward and for- ward, terminate in tendinous fibres, which spread out into a broad aponeurosis. This aponeurosis, joined with that of the opposite muscle, along the median line (25), covers the whole fiftnt of the abdomen; above, it is connected with the lower border of the pectoralis major; below, its- fibres are closely aggregated together, and extend ob- liquely across from the anterior superior spine of the ilium, to the spine of the os pubis and the linea ilio-pectinea. In the median line it interlaces with the aponeurosis of the opposite muscle, forming the linea alba (25), and extends from the ensiform cartilage (XXXVIIL, 33) to the sym- physis pubis (VI., g). This broad 'muscle moves the ribs and abdomen in breathing. ■ Linea alba (25). A tendinous cord along the middle line of the abdomen whef e the muscles of the two sides meet., ' Poupart's Ligament (26) is a portion of the expaiJfcive aponeuroses of the external oblique muscle, extending from 44 A COMPEND'OF the anterior superior spine of the ilium to the spine of the OS pubis. It is a broad band folded inward, and con- tinuous below with the fascia lata. . Fascia latafemorin (27) is the deep areolar tissue invest- ing the muscles of the thigh. It is attached above to Poupart's ligament and the crest of the ilium, behind to the margin of the sacrum and coccyx, internally to the pubic arch and linea ilio-pectinea, and below to a|l the prominent points around the knee joint, the condyles of the femur, tuberosities of the tibia, and the head of t-he ■ fibula. ANTEEIOE MUSCLES OF THE EIGHT AEM. . ' (in.) , Biceps (28) occupies the whole of the anterior: surface of the arm and is attached by its short tendinous head to the coracoid process, and by its long head to the upper margin of the glenoid cavity in the scapula above, and be- low, by a flattened tendon inserted into the back part of the tuberosity of the radius. It bends the arm at the el-' bow joint. Triceps (29, 30) extends the entire length of the back of the humerus. In its upper portion it is divided into three heads. Its middle or scapular head, arising by a flattened tendon from a rough triangular depression be- low the glenoid cavity, blends at its upper part with the capiular and glenoid ligaments. The external head arises r from the posterior surface of the shaft of the humerus. ANATOMY AND PHYSIOLOGY. 4S The internal head also arises from the posterior surface of the shaft of the humerus, and the internal border of the humerus and internal intermuscular septum. These three divisions (5t the muscle converge to a com- mon tendon, which is inserted into the back part of the under surface of the olecranon process. This is the great extensor of the forearm, serving when the arm is bent to return it to its former position. Supinator longus (31) arises from the. upper two-thirds of the external condyloid ridge of the humerus, and from the external intermuscular septum. The fibres terminate above the middle of the forearm in a flat tendon which is inserted into the styloid process of the radius. This is one of the extensors of the forearm. (For other muscles of arm see VII.) MUSCLES OP THE HAND. IV. Muscles and Tendons of the palm (a, b). IX. Abductor pollicis (1) arises from the ridge of os trape- zium and annular ligament and is inserted by a thin, flat tendon into the radial side of the base of the first phalanx of the thumb. This muscle, with the opponens pollicis and flexor brevis pollicis, compose the fleshy portion of the inside of the thumb. Palmaris hrevis (2) arises by tendinous fasciculitfrom the annular ligament and palmar fascia; its fleshy fibres 46 A COMPEND OF *,. pass horizontally inward to be inserted into the skin on the inner bordol- of the palm of the hand. Flexor tendons (3), Muscular fibres (4) forming sheath of flexor tendon. Lumbricales are four small, fleshy fasciculi, accessories to the deep flexor muscle, and are attached to the four fingers. C. Anterior annular ligament of wrist (1) is a strong, fi]Drous band, which arches over the carpus, beneath which pass the flexor tendons of the fingers. There is also a ligament across the back of the wrist, which forms a sheath for the extensor tendons in their passage to the fingers, having attachments both to the ulna and the radius, and some of the bones of the carpus.* It is called the posterior annular ligament. ^ Palmaris Brevis (2) (see IX., 1). Abductor Minimi Digiti {i) arises from. the pisiform bone, and from an expansion of the- tendon of the flexor . carpi ulnaris, and terminates in a flat tendon which is inserted into the ulnar side of the base of the first phalanx of the little finger. CII. Extensor carpi radialis longus (1) ; Extensor primi in- ter nodii pollicis{%)\ Extensor ossis me^aoarpi pollicis (3); Extensor secundi internodii pollicis (4) ; Extensor indicia (5) ; ^xtensor carpi radialis brevis (6). The foregoing six muscles are for the straightening' of the tbKTEb .and fingers. ANATOMY AND PHYSIOLOGY. 47 Abductor indicis (7) and Adductor pollicis (8) are aids both to the extensors and flexors in certain movements. MUSCLES OF THE LEG. Adductor longus (46), Adductor magnus (48), and Ad- ductor brevis arise from the ■ pubic portion of the pelvis, and their radiating fibres attach themselves to the inner side of the femur from the lesser trochanter above to the internal tuberosity below. The aponeurosis of the adduc- tor magnus is pierced close to its attachment to the femur in its lower portion by the foramen of the femoral vessels. Sartorius (47), the longest muscle in the body, is flat, narrow, and ribbon-like; it arises by tendinous fibres from the anterior superior spinous process of the ilium and the upper half of the notch below it, passes obliquely across the upper and anterior part of the thigh, from the outer to the inner side of the limb, then descends vertically, as far as the inner side of the knee, passing behind the inner condyle of the femur, and terminates in a tendon, which, curving obliquely forward, expands into a broad aponeu- rosis, inserted into the upper part of the inner surface of the shaft of the tibia, nearly as far forward as the crest. This is sometimes called the tailor muscle from its uses in crossing the legs. Quadriceps extensor includes four muscles on the front of the thigh. It is the great extensor muscle of tljg leg, forming a large, fleshy mass, which covers the front and 48 A COMPENb OF • ^ sides of the femur, being united below into a single tendon, , attached to the tibia, and above subdividing into separate portions, which have received distinct names. Of these, one occupying the middle of the thigh, connected above with the ilium, is called Bectus Femoris (50), from its straight course. The other divisions lie in immediate con- nection with the shaft of the femur, which they cover from the condyles to the trochanters. The portion on the outer side of the femur is termed the Vastus extenms (49) ; that covering the inner side, the Vastus internus; and that covering the front of the fepiur, the Crureus. The two latter portions are, however, so intimately blended as to form but one muscle. The tendons of the different portions of the Quadriceps extensor unite at the lower part of the thigh, so as to form a single strong tendon, which is inserted into the up- per part of the patella. More properly the patella may be regarded as a sesamoid bone, developed in the tendon of the Quadriceps; and the ligamentum patellse which is continued from the lower part of the patella to the tuber- osity of the tibia, as the proper tendon of insertion of the muscle. Tibialis anticus (51) is on the outer side of the tibia, and arises from the outer tuberosity and upper two- thirds of the ext,ernal surface of its shaft and adjacent parts. The fibres pass downward and develop into a ten- don which passes through the anterior annular ligament 5| and is inserted into the internal cuneiform bone and base of tbj^ metatarsal bone of the great toe. Uxtensor diffitorzim communis longus (53) arises from ; ANATOMY AND PHYSIOLOGY. 49 tte outer tuberosity of the tibia and the upper three- fourths of the anterior surface of the shaft of the fibula and adjacent fascia. It terminates in three tendons which pass through a canal in the annular ligament with the peroneus tertius, run across the dorsum of the foot and are inserted in the second and third phalanges of the four lesser toes, the innermost tendon being subdivided into two. The Peroneus tertius is part of this muscle and might be described as its' fifth tendon, which is inserted into the dorsal surface of the base of the metatarsal bone of the little toe on the inner side. VIII. Tendinous portion of Vastus externus (53) (see V., 49). Pectineus (54) has its origin in the surface of bone between the pectineal eminence and spine of the pubes, and is at- tached to the crest of the pubis. The fibres pass down- ward and outward and backward to be inserted in a rough line, leading from the trochanter minor to the linea aspera. This muscle and the three adductors (see V., 46, 48) ad- duct the thigh powerfully, especially in horse exercise. Addtictor longus (55), Adductor magnus (56), Vastus ex- ternus (57) (see V., 46, 48, 49). Ligamentum patellce (58) is that portion of the com- mon tendon of the extensor muscles of the thigh which is continued from the patella to the tubercle of the tibia,- supplying the place of an anterior ligament. It is a strong, flat band, about three inches in length, attSched above to the apex of the patella and the rough depression 4 50 A COMPEND OF on its posterior surface ; below to the lower part of the tuberosity of the tibia; its superficial fibres being contin- uous across the front of the patella with those of the ten- don of the Quadriceps extensor. ' Extensor digitorum communis longus (59, 61) (see V., 53). Peroneus longus, brevis (60). These two muscles are attached to the shaft of the fibula, and the fibres passing downward develop into tendons which pass together through the same groove behind the external malleolus. The brevis then passes through a separate sheath on the outer side of the os calcis, above that for the tendon of the longus, and is finally inserted in the dorsal surface in the base of the metatarsal bone of the little toe on its outer side. The tendon of the longus, after passing the groove, as above, is then reflected forward across the outer side of the OS calcis; having reached the outer side of the cuboid bone, it runs in a groove on the under surface of that bone '\ and crosses the sole of the foot obliquely and is inserted into the outer side of the base of the metatarsal bone of the great toe. XXXVI. Gluteus maximus (1) is a thick, fleshy mass of large size, of much importance in sustaining the trunk in an erect position. The fibres are remarkably coarse. It ai-ises from the superior curved line of the ilium, and the • portion of b'one including the crest, immediately behind - it ; from the posterior surface of the last piece of the sa- anatOmv and physiology. Jl crum, the side of the coccyx, and posterioj surface of the great sacro-sciatic and posterior sacro-iliac ligaments. The fibres are directed obliquely downward and outward; those forming the upper and larger portion of the muscle (after converging somewhat) terminate in a thick tendinous lamina, which passes across the great trochanter and is in- serted into the fascia lata covering the outer side of the thigh, the lower portion of the muscle being inserted into the rough line leading from the great trochanter to the linea aspera, between the Vastus externus and Adductor magnns. Gluteus medius (2) is a broad, thick, radiated muscle, situated on the outer surface of the pelvis. Its posterior third is covered by the gluteus maximus; its anterior two- thirds by the fascia lata, which separates it from the in- tegument. It arises from the outer surface of the ilium, between the superior and middle curved lines, and from the outer lip of that portion of the crest which is between them; it also arises from the dense fascia (gluteal apo- neurosis) covering its anterior part. The fibres converge to a strong flattened tendon, which is inserted into the ob- lique line which traverses the outer surface of the great trochanter. Gluteus minimus, the smallest division of the glutei, is immediately beneath the two preceding. Semitendinosus (3) arises from the tuberosity of the ischium, by a tendon common to it, and the long head of the biceps, and from an aponeurosis which connects the ad- jacent surfaces of the two muscles- to the extent of about three inches after their origin. It forms a fusiform muscle, 52 , A compeNd of which, passing downward and inward, terminates a little below the middle of the thigh in a long, round tendon which lies along the inner side of the popliteal space, then curves around the inner tuberosity of the tibia and is in- serted into the upper part of the inner surface of the shaft of that bone, nearly as far forward as its anterior border". This tendon lies beneath the expansion of the sartorius and below that of the gracilis, to which it is united. Semimembranosus (6) is situated at the back part and inner side of the thigh. It arises by a thick tendon from the upper and outer facet, on the back part of the tuber- osity of the ischium, above and to the outer side of the bi- ceps and semitendinosus, and is inserted into the inner and back part of the inner tuberosity of the tibia, beneath the internal lateral ligament. The tendon of this muscle, at its lower extremity, divides into three portions: the , middle portion is inserted in the inner tuberosity, the in- ternal portion is horizontal and passes to be inserted into a groove along the inner side of the internal tuberosity. The posterior division passes upward and backward to be inserted into the , back part of the outer condyle of the femur, forming the chief part of the posterior ligament of the kne'e joint. The tendons of the two preceding muscles, with those of the gracilis and sartorius, form the inner hamstring. The muscles of this region are supplied by the great sciatic nerve. The hamstring muscles ilex the leg upon the thigh. When the knee is semi-flexed the biceps, in consequence of its oblique direction downward and outward, rotates ANATOMY AND PHYSIOLOGY. S3 the leg slightly outward; and the semimembranosus, in consequence of its ohlique direction, rotates the leg inward, assisting the popliteus. Taking their fixed point from below, these muscles serve to support the pelvis upon the head of the femur, and to draw the trunk directly back- ward in the form of an arch. Biceps (i) is a large muscle of considerable length, sit- uated on the posterior and outer aspect of the thigh. It arises by two heads : one, the long head, arises from the lower and inner facet on the back of the tuberosity of the ischium, by a tendon common to it and the semitendinosus. The femoral or short head arises from the outer lip of the linea aspera, between the adductor magnus and vastus externus, extending from a short distance below the in- sertion of the gluteus maximus, to within two inches of the outer condyle; it also arises from the external inter- muscular septum. The lower extremity develops a ten- don which is inserted into the outer side of the head of the fibula. At its insertion the tendon divides into two portions, which embrace the external, lateral ligament of- the knee joint, a strong prolongation being sent forward to the outer tuberosity of the tibia, which gives off an ex- pansion to the fascia of the leg. The tendon of this mus- cle forms the outer hamstring. Vastus externus (5) (see V., 49). Gastrocnemius (9, 10), Internal head (7), External head (8). This muscle forms the greater part of the calf of the leg. It arises by two heads which are connected to the condyles of the femur by two strong, flat tendons. The inner "head, the larger, and a little the more posterior, 54 A COMPEND OF arises from a depression of the upper and back part of the inner condyle. The outer head arises from the upper and back part of the external condyle, immediately above the origin of the popliteus. Both heads, also, arise by a few tendinous and fleshy fibres from the ridges which are con- tinued upward from tlie condyles to the linea aspera. Each tendon spreads out into an aponeurosis, which covers the posterior surface of that portion of the muscle to which it belongs; that covering the inner head being longer and thicker than the outer. From the anterior surface of these tendinous expansions muscular fibres are given oS. ' The fibresin the median line which correspond to the ac- cessory portions of the muscle derived from the bifurca- tions of the linea aspera, unite at an angle upon a median tendinous raphe below ; the remaining fibres converge to the posterior surface of an aponeurosis which covers the front of the muscle, and this, gradually contracting, unites with the tendon of the soleus and forms with it. the Tendo Achillis. Soleus (1) is a broad, flat muscle situated immediately beneath the preceding., It arises by tendinous fibres from the back part of the head of the fibula, and from the upper third of the internal surface of its shaft; from the oblique line of the tibia and from the middle third of its- internal border ; some fibres also arise from a tendinous arch placed between the tibial and fibular origins of the - muscle beneath which the posterior tibial vessels and nerve pass. The fibres pass backward to an aponeurosis which covers the posterior surface of the muscle, and this, gradually becoming thicker and narrower, joins with the ANATOMY AND PHYSIOLOGY. 55 tendon of the gastrocnemius, and forms with it the Tendo Achillis. Plantaris is a small muscle between the Soleus and Gas- trocnemius, near their origin having a peculiarly long ten- don which extends to the tendo Achillis. Its characteristics are not uniform, as the muscle is , sometimes double and sometimes absent altogether, and its tendon is occasionally lost m the internal annular ligament or in the fascia of the leg. Tendo Achillis, the common tendon of the Gastrocne- mius and Soleus, is the thickest and strongest tendon in the body. It is about six inches in length, and formed by the junction of the aponeurosis of the two preceding mus- cles. It commences about the middle of the leg, but re- ceives fleshy fibres on its anterior surface nearly to its lower end. Gradually becoming contracted below, it is inserted into the lower part of the posterior tuberosity of the OS calcis, a synovial bursa being interposed between the tendon and the upper part of the tuberosity. The tendon spreads out somewhat at its lower end, so that its narrow- est part is usually about an inch and a half above its in- sertion. The tendon is covered by the fascia and the in- tegument, and is separated from the deep muscles and vessels by a considerable interval filled up with areolar and adipose tissue. Along its outer side, but superficial to it, is the external saphenous vein. 56 A COMPEND OF MUSCLES AND TENDONS OF THE FOOT. XOII. Anterior annular ligament (1) consists of a superior or vertical portion, which binds down the extensor tendons as they descend on the front of the tibia and fibula, and an inferior or horizontal portion, which retains them in connection with the tarsus, the two portions being con- nected by a thin intervening layer of fascia. The vertical portion is attached externally to the lower end of the fibula, internally to the tibia, and above is continuous with the fascia of the leg ; it contains two separate sheaths, one internally, for the tendon of the tibialis anticus, one ex- ternally, for the tendons of the Extensor longus digitorum and Peroneus tertius ; the tendon of the Extensor proprius poilicis and the anterior tibial vessels and nerve pass be- neath it, but without any distinct sheath. The horizontal portion is attached externally to the upper surface of the OS calcis, in front of the depression for the interosseous ligament, and internally to the inner malleolus and plantar fascia. It contains three sheaths; the most internal for the tendon of the Tibialis Anticus, the next in order for the tendon of the Extensor proprius poilicis, and the most ex- ternal for the Extensor longus digitorum and Peroneus tertius: the anterior tibial vessels and nerve lie altogether beneath it. These sheaths are lined by separate , synovial membranes. (See VIII.) Internal Annular ligament is a strong fibrous band which extends from the inner malleolus above to the internal ANATOMY AND PHYSIOLOGY 57 margin of the os calcis below, converting a series of bony grooves in this situation into osseo-fibrous canals, for the passage of the tendons of the Flexor muscles and vessels into the sole of the foot. External Atmular ligament extends from the extremity of the outer malleolus to the outer surface of the os calcis; it binds down the tendons of the Peronei muscles in their l^assage beneath the outer angle. The two tendons are inclosed in one synovial sac. Extensor digitorum communis longus (3) (see V., 52). Peroneus tertius (3) (see V., 52). Abductor digiti minimi (4) lies along the outer border of the foot. It rises by a very broad origin from the outer tubercle of the os calcis, from the under surface of the os calcis in front of the tubercle, from the plantar fascia, and the intermuscular septum between it and the Flexor brevis digitorum. Its tendon, after gliding over a smooth facet on the under surface of the base of the fifth metatarsal bone, is inserted with the short Flexor of the little toe into the outer side of the base of the first phalanx of the little toe. It is supplied by the external plantar nerve. Extensor digitorum communis brevis. (5) ia abroad, thin muscle, which arises from the outer side of the os calcis, in front of the groove for the Peroneus brevis; from the ex- ternal calcanei-astragaloid ligament, and from the hori- zontal portion of the anterior annular ligament. It passes obliquely across the dorsum of the foot and terminates in four tendons. The innermost, which is the largest, is in- serted into the first phalanx of the great toe crossing the dorsalis pedis artery; the other three into the outer sides 58 A COMPEND OF of the long extensor tendons of the second, third, and fourth toes. XCVIII. Internal malleolus {1), a rough prominence on the inner side of the lower extremity -of the tibia, for the attachment of the annular ligament. ^Anterior tibial tendon (3) (see V., 51). ' Adductor pollicis pedis (3) is a large, thick fleshy mass, passing obliquely across the foot, and occupying the hollow- space between the four outer metatarsal bones. It arises from the tarsal extremities of the second, third, and fourth metatarsal bones, and from the sheath of the tendon of the Peroneus longus, And is inserted, together with the outer portion of the flexor brevis pollicis, into the outer side of the base of the first phalanx of the great toe. Tendo extensoris pollicis pedis longi (4). Extensor ten- dons of the toes. XCVII. Os Calcic (1) (see XLVI., LXVI.). Eascia Plantaris (2), the densest of all the fibrous mem- branes, is divided into a central and two lateral portions. The central portion is narrow behind and attached to the inner tubercle of the os calcis, and becoming broader and thinner in front, divides opposite the middle of the meta- tarsal bones into five processes, one for each of the toes. Bach of these processes divides into two slips which embrace the sides of the flexor tendons of the toes, and are inserted ANATOMY AND PHYSIOLOGY. 59 in the sides of the metatarsal bones and into the trans- verse metatarsal ligament, thus forming a series of arches, through which the tendons i f the short and long flexors pass to the toes: The lateral portions of the fascia al'e thinner than the central piece, and cover the sides of the foot. Abductor pollicis (3) lies along the inner border of the foot. It arises from the inner tubercle on the outer sur- face of the 08 calcis ; from the internal annular ligament ; from the plantar fascia; and from the intermuscular sep- tum between it and the Flexor brevis digitorum. The fibres terminate in a tendon which is inserted together with the innermost tendon of the Flexor brevis pollicis, into the inner side of the base of the first phalanx of the great toe. Abductor minimi digiti (4) (see XCII., 4). Flexor brevis digitorum (5) lies in the middle of the sole of the foot, immediately beneath the plantar fascia, with which, it is firmly united. .It arises by a narrow ten- dinous process from the inner tubercle pf the os calcig,- from the central part of the plantar fascia; and from the intermuscular septa between it and the adjacent muscles. It passes forward and divides into four tendons. Opposite the middle of the first phalanges each tendon presents a longitudinal slit, to allow the passage of the corresponding tendon of th^ Flexor longus digitorum; the two portions form a groove for the reception of that tendon. The ten- don of the short fiexor then reunites and immediately di- vides a second time into two processes, which are inserted into the sides of the second phalanges. The mode of di- 6o A COMPEND OF vision of the tendons of the Flexor brevis digitorum and. their insertion into the phalanges is analogous to the Flexor sublimus in the hand. It is supplied by the inter- nal plantar nerve. Tendon of the flexor longus pollicis (6). This is, one of the deep muscles of the back part of the leg. Its tendon passes through a groove on the posterior surface of the tibia, external to that for the Tibialis posticus and Flexor longus digitorum; it then passes through another groove on the posterior extremity of the astragalus, and along a third groove beneath the lesser process of the os calcis, into the sole of the foot, where it runs forward between the two heads of the Flexor brevis pollicis and is inserted into the base of the last phalanx of the great toe. Lumbricales (7) are four small muscles accessory to the tendons of the Flexor longus digitorum. They arise from the tendons of the lon^ flexor as far back as their angle of division, each arising from two tendons, except the inter- nal one. Each muscle terminates in a tendon which passes forward on the inner side of each of the lesser toes, and is inserted into the expansion of the long extensor and base of the first phalanx of the corresponding toe. THE SKIN AND ITS APPENDAGES. LXXXII, The skin is the principal seat of the sense of touch, and may be regarded as a covering for the protection of the deeper tissues. It is also an important excretory and ab- sorbing organ, on which account it is indispensable to the ANATOMY AND PHYSIOLOGY. , 6l life and health of the body. It consists of two layers, the derma, or cutis vera (true skin) (c) and the epidermis, or cuticle (a). On the surface of the former layer are the sensitive papillae; and within or imbedded beneath it are the sweat glands (e), hair follicles (d), and sebaceous glands. The derma, or true skin, is tough, flexible, and highly elastic,4n order to defend the internal parts from violence. It consists of fibro-areolar tissue, intermixed with numer- ous blood-vessels, lymphatics, and nerves. From the dif- ferences in the structure of the cutis at different parts, it is usual to describe it as consisting of two layers: the deeper layer, or corium, and the superficial or papillary layer. , The corium consists of strong interlacing fibrous bands, composed chiefly of the white variety of fibrous tissue, but containing also some fibres of the yellow elastic tissue, which vary in amount in different parts. The corium varies in thickness. Thus it is thicker in the regions exposed to pressure, as the palm of the hand and the sole of the foot; thicker, also, on all portions most exposed, and thinner on less exposed portions. In the eyelids it is exceedingly thin and delicate. The- areolm are occupied by adipose tissue, hair follicles, and the sudoriferous and sebaceous glands. They are the channels by which the vessels and nerves are distributed to the more superficial strata of the corium and to the papillary layer. The papillary layer is situated upon the free surface of the corium. It consists of numerous small, highly-sensi- tive, and vascular eminences, the papillae, which rise per- 62 A COMPEND OF pendicularly from its surface and form the essential ele- ment of the organ of touch. The papillae are conical-shaped eminences, haying a round or blunted extremity, occasion- ally divided into two ormore parts, and connected by their base with the free surface of the corium. The epidermis, or cuticle (scarf-skin), is an epithelial structure accurately moulded on the papillary, layer of the derma. It forms a defensive covering to the surface of the true skin, and limits the evaporation of watery vapor from its free surface. It varies in thickness in different parts of the body as exposure and pressure are incidental to them. The black color of the skin in the negro and the tawny color among some of the white races is due to the pres- ence of pigment in the. cells of the cuticle. This pig- ment is more especially distinct in the cells of the deeper layer, or rete mucosum, and is similar to that found in the choroid. As the cells approach the surface and desiccate, the color becomes partially lost. The af/ertgs which supply the skin divide into numerous branches in the subcutaneous tissue ; they then pass through the areolae of the corium and divide into a dense capil- lary plexus, which supplies the sudoriferous and sebaceous glands and the hair follicles, terminating in the superficial layers of the corium, by forming a capillary network, from which numerous fine branches ascend to the papillae, f The lymphatic vessels are arranged in a minute plexiform network in the superficial layers of the corium, where they become interwoven with the capillary and nervous plexuses. The nerves which supply the skin ascend with the ves- ANATOMY AND PHYSIOLOGY. 63 sels through the areolas of the deep layfers of the corium to the more superficial layers, where they form a minute plexiform mesh. Prom this plexus the primitive nerve fibres pass to be distributed to the papillae. The nerves are most numerous in those parts which manifest the greatest sensibility. The appendages of the skin are the nails, the hairs, the sudoriferous and sebaceous glands and their ducts. The nails and hairs are peculiar modifications of the epider- mis, consisting essentially of the same cellular structure as that membrane. The skin is a vital organ, by which is meant that its func- tions are indispensable to life and health. The insensible perspiration must not be interrupted or death will speedily ensue, as thus the injurious elements that should be ex- pelled from the body are retained in it to poison the blood and thus overtax the vital organs within the body. THE ALIMENTAEY CANAL. ±he human body is supported by elements derived from the air we breathe and from the food we eat. The animal and Vegetable substances of which the food is composed - contain elements not nutritious, and these need to be sep- arated by chemical action. The nutritious qualities are thus made available by a process called digestion. The Digestive tract or alimentary canal consists of the mouth, pharynx, oesophagus, stomach; the duodenum, je- junum, and ileum, together forming the small intestine; and the colon — ascending, transverse, and descending — ■ 64 A COMPEND OF , and the rectum (see XIII., XV., XXIV. in manikin and its index). The various substances proper for food containing the nutritious elements necessary for the support of the body are both solid and fluid.' The fluids are taken into, the mouth and pass immediately through the pharynx and (tesophagus to the stomach; but the soljds are retained in the mouth, to be prepared for the proper change they are to undergo when they pass into the stomach. This prep- aration is accomplished by the simultaneous grindinjg mor ^ tions of the teeth and the action of the tobgue and inter- nal muscles of the mouth, while the necessary disclxarge of ihe salivary glahfis supplies the needed moisture to reduce the mass to the consistency necessary to pass, it to the stomach. These glands are six in number — three on each Bide — two in the front portion of the mouth under the tongue, called the sublingual glands ; two below the jaw in J' the anterior part of the submaxillary triangle of the neck, called the submaxillary glands; and two near the ear, be- ing larger than the others, lying on the side of the face ^immediately below and in front of the external ear, called ■ the .parotid glands. . ' The duct of the submaxillary, called Wharton's duct, and the numerous ducts of the sublingual open in close proximity to each other under the tongue; but the orifice of tiie duct of thej)arotid, called Steno's duct, opens upon •the inner surface of the cheek opposite the second molar tobth of the upper jaw (XXXI., 1, 3, 4, manikin and its index). . ■ '. ANATOMY AND PHYSIOLOGY. 65 IN THE MOUTH. The Tiwrd palate is bounded in front and at the sides by the alveolar arches and gums; behind it is continuous with the soft palate. It is covered by a dense structure formed by the periosteum and mucous rnembrane of the mouth, which are intimately adherent together. The so/if palaie is a movable fold, suspended from the , , posterior border of the hard jSlate and f oriiiing an incom- plete septum between the mouth and pharynx. Its upper " border ' is attached to the posterior margin, of the hard^ palate, and its sides are blended with the pharynx. Its lower border is free. Hanging. from the middle of its lower border is a small conical-shaped pendulous process -called the uvula. The space left between the arches of the pajate on the '- two sides is called the isthmus of ^the fauces. It is baunded above by the free margin of the palate; befow by the tongue and on each side by the pillars, of the soft palate *. and tonsils. , The tonsils are two glandular organs situated one on each side of the fauces, between the anterior and poste- , rior pillars of the soft palate. ■ They are of a rounded form, and vary considerably in size in different individuals (LXXVL, XXVIL, XXVIJL). " / The Pharynx (XXXIII., 6) is that part of the alimeh- tary. canal wjiich is placed behind the nose, mouth, and . larynx. It is a musculo-membranous sac somewhat coni- 5 . •• ' , 66 A COMPEND OF cal in form, with the base upward and the apex downward,.3 extending from the under surface of the skull to the cri- ' coid cartilage in front, and the fifth cervical vertebra be- hind. It has seven openings communicating with it; the two nares, the two Eustachian tubes, the mouth, larynx, and oesophagus. The posterior nares are the i^wp large apertures situated at the upper part of the anterior wall of the pharynx;'^ The CBSophageal opening is the lower contracted portion of the pharynx. „ The oesophagus is a i^mbranous canal, about nine inches in length, extending from the pharynx to the stom- ' ach (XV., 14). In the neck it is behind the trachea, the ■ thyroid gland, and thoracic duct; behind, it rests upon the vertebral column and Longiis colli muscle; the caro- . tid arteries are on each side of it. In the thorax it passes across the transverse part of the aortic arch, and descends along the right side of the aorta, nearly to the diaphragni, ' where it passes in front of the artery pravious to entering the abdomen. The Diaphragm is a thin musculo-fibrous septum, placed , obliquely^ at the junction of the upper with the middle tjiird of the trunk, and separating the thorax from the abdomen, forming the floor of ' the ' former cavity and the roof of the latter. It arises from the whole of the inter- nal circumference of the thorax, being attached, in front, by fleshy fibres, to the ensiforin cartilage; on either side,-' to the inner surface of the cartilages and bony .portions of . the six or seven inferior ribs, interdigitating with the trans- , versalis; and behiiid, to two aponeurotic arches, nampd- ANATOMY AND PHYSIOLOGY. ^J the ligamentum arcuatnm externum and internum, and to vthe lumbar vertebrae. The action of the diaphragm modifies considerably the size of the chest and the position of the thoracic and ab- dominal viscera. During a forced inspiration, the .ca'vitj of the thorax is enlarged in the vertical direction, from two to three inches. The abdominal viscera are also pushed down (the liver to the extent of nearly three inches), so that these organs are no longer protected by the ribs. During expiration, when the diaphragm is passive, it is pushed up by the action of the abdominal muscles; the cavity of the abdomen (with the organs contained in it) encroaches upon the chest, by which the lungs and heart are compressed upward, and the vertical diameter of the thoracic cavity diminished. The diaphragm is passive when raised or lowered by the abdominal organs inde- pendently of respiration, in proportion as they are large or small, full or empty; hence the oppression felt in the chest after a full meal, or from flatulent distention of the stomach and intestines; In all expulsive acts the diaphragm is called into action, tq give additional power to each ex- pulsive effort, as before sneezing, coughing, laughing, crying, etc. (XVI., 27, 27). Physiologists have experimented much to ascertain" whether the food or any o,f its ingredients pass through any chemical change, by contact with the salita, but it is quite well established that the saliva is only necessary to soften the solids and .prepare them for passage to. the stomach. The general sensibility of the tongue enables this organ 68 A COMPEND OF to appreciate the physical condition of the food and its readiness for deglutition. At the same time its muscular apparatus provides for its movement in every direction. When the alimentary material is finally reduced, by the saliva and mastication, to a pasty and hojnogeneous con- ' dition, the softened mass is collected from every part of ' the mouth by the movements of the tongue, brought tor gether upon its upper surface, and pressed backward through fauces into the pharynx and oesophagus. Here it passes beyond the control of the will. It is then grasped by the muscular .fibres of the oesophagus, and by a contin- ouus and rapid peristaltic action is carried downward into the stomach. - The alimentary canal is about six times the length of the body, and as the food passes through it, it is acted upon by fluids from the mucous membrane of the canal, and by those from certain accessory glands. These act u^on it in such a way as to separate the nutritious from the innutritious portions, the former to be mingled with the blood, and the latter to be expelled from the body. Throughout this passage it is lined by a muCous mem- brane and a muscular coat. The muscular coat, by its alternate contractions and relaxations, ca]*ri6s the food dbwnward. Its fibres differ in its different portions, to be accommodated to the various movements necessary as the work of digestion and assimilation proceeds. ANATOMY AND PHYSIOLOGY. 69 THE ABDOMEN.. XVI. The Abdomen is the largest cavity in the body, and is sepatated, below, from the pelvic cavity by the brim of the pelvis. It is bounded in front and at the sides by the lower ribs, the Transversalis muscle, and the venter ilii; behind, by the vertebral column and the Psoas and Quad- ratus lumborum muscles; above, by the diaphragm; be- low, by the brim of the pelvis. The abdomen contains 'the greater part of the alimen- tary canal, some of the accessory organs to digestion, viz.,. the liver, pancreas, and spleen, and the kidneys and supra' renal capsules. Most of these structures, as well as the wall of the cavity in which they are contained, are cov- ered by an extensive and complicated serous membrane, the peritoneum. The apertures found in the walls of the abdomen for the transmission of structures to or frorji. it are the umbilicus, the caval opening in the diaphragm for the transmission of the infetioi- vena cava; the aortic opening for the pas- sage of the-aorta, vena azygos, and thoracic duct; and tfie (esophageal opening for the cesophagus and pneumogastric nerves. Below there are two apertures on each side : one for the passage of the femoral vessels and the other for the passage of cords and ligaments. The stomach is an expansion of the canal, from nine to twelve inches long in its transverse measurement, and JO A COMPEND OF about four inch£s vertically. It is located in the upper left-hand side of the abdominal cavity,. behind and below the lower ribs, immediately under the heart and liver. Its mucous membrane is thick, smooth, soft, and velvety; and, in the adult, is generally of a pale straw color. When at rest its surface is thrown into numerous plaits or rugae, ' which have a general longitudinal direction. These en- tirely disappear when the stomach is distended (XIII., 1) (LXXXVL, LXXXVII.). As soon as the food enters the stomach from the oesoph- agus there exudes from this mucous membrane a pow- erful solvent called the gastric juice, whose qualities are such that, while it performs its proper chemical work on the contents of the stomach, it has no effect whatever on the living tissues of the stomach itself, although it will act on these tissues after death. Improper food, irregular diet, gluttony, and the exces- sive use of alcoholic beverages tend to interrupt the func- tions of this organ by neutralizing the gastric juice or de- stroying the mucous membrane, so that the preparation of the mass for subsequent -action in the intestines is not properly effected, and thus healthy nutrition is retarded (XXVI., XXVII.). Indeed, the entire alimentary canal and its accessory organs are more or less retarded in their functions and tend to organic disintegration by these die- tary irregularities, so that the complicated functions are disturbed ; and either abnormal enlargement of the organ or the opposite tendency to become shrivelled ensues, and inflammatory and ulcerous conditions are generated in the . intestines and acute and malignant diseases result. ANATOMY AND PHYSIOLOGY. 7I As soon as the food enters the stomach and the gastric juice has been added, the muscular coat begins a kneading ot stirring motion, which continues until the entire mass has been affected. The opening through which the contents of the stom- ach pass out is at its right extremity and is called the pylo- rus. When the food has been properly changed by the action of the gastric juice, it is called chyme, and passes out through this orifice, which is guarded by a valve, into ■ the duodenum, or second stomach (XIII., 3)., Here it re- ceives the bile from the liver and the pancreatic juice from the pancreas. The Pancreas is a gland somewhat like the salivary glands, and its fluid closely resembles saliva in its general charac- ter. It extends across the upper part of the abdominal cavity behind the stomach, is from six to eight inches long and one and a half inches wide, and somewhat in the form of a dog's tongue. Its right extremity is in contact with the duodenum, and its left reaches to the spleen. On the posterior side is a lobular fold of the gland, which is some- times separated from it and is termed the lesser pancreas (XIII., 2; XVI., 36). Interposed between the pancreas and the first lumbar vertebra are the superior mesenteric artery and vein, the commencement of the portal vein, the vena cava, the aorta, the upper portion of the left kidney and its capsule, and the corresponding renal vessels (see manikin and index, XVI.). Through the entire length of the gland runs the vessel or duct which collects and conveys its fluid to the duodenum, This duct has various 'branches ramifying 72 A COMPEND OF through the substance of the gland; it also receives a branch from the lesser pancreas behind it. The opening of the pancreatic duct is usually in conjunction with the CQmmon duct from the liver, but sometimes they enter at different points. " The Liver is a glandular organ of large size, intended mainly for the secretion of the bile, but effecting other im- portant changes in certain constituents of the . blood Jn its ■ paissage through the gland. It is the largest gland in the body, weighing from three to four pounds. It measures in its transverse diameter from ten to twelve inches; from six to seven in its antero-posteripr ; and is about three,inches thick at the back part of the right lobe, which is, the thick- est part (XIV., 1; XVI., 28; XXXIV.). Its upper surface is convex, directed upward and forward, smooth, covered by peritoneum. It is in relation with the under surface of the diaphragm; and below, to a small ex- tent, with the abdominal parietes. The surface is divided into two unequal lobes, the right and left, by a fold of peri- toneum, the suspensory or broad ligament. Its under surface is concave, directed downward and back- ward, and in relation with the stomach and duodenum, the hepatic flexure of the colon, and the right kidney and suprarenal capsule. The surface is divided by a longitu- dinal fissure into a right and left lobe. The posterior border is rounded and broad, and connected to the .diaphragm by the coronary ligament; it is in relation with the aorta, the vena cava, and the crura of the dia- phragm. The anterior border is thin and sharp, and marked, op- ANATOMY AND PHYSIOLOGY. 73 posite the attachment of the broad ligament, by a deep notch. In adult males this border usually corresponds with the margin of the ribs; but in women and children it usu- ally projects below the ribs. Thus it is situated in the highest part of the abdominal cavity on the right side im- mediately beneath the diaphragm, in contact with the upper" portion of the pyloric end of the stomach, the duodenum,' right kidney, and transverse colon,' Its large size, complex structure, and its relations to the alimentary canal are evidence tliat it has an important place in the economy of human life. For all this its functions are very imperfectly understood. The secretiSn formed within it is called bile, which is retained in a small sac called the gall-bladder, and, as occasion requires, it' passes through the common duct of the liver, called ductus com- munis choledochus, to the duodenum to mingle with the •food in course of digestion. ' ' At this stage in the digestive progress the phyme from the stomach is in contact with the bile from the liver and the juice from the pancreas by which it is reduced to a condition in which the nutritive and iniiutritive qualities of the food may be separated and properly appropriated by the work to be accomplished in its passage through the jejunum and ileum. It is quite satisfactorily established that the function of the pancreatic juice is to convert the fatty elements of the food into chyle, and so prepare it for absorption by the lac- teals that it may be passed into the blood. But exactly what the function of the bile is, in this connection, baffles the skill of the physiologists. It is certain, however, as 74 /• COMPEND OF numerous experiments on the lower animals have proven,, that its presence is indispensable to the completion of the digestion and assimilation in the human organism, as death will speedily ensue wheh it is absent. The small intestine, from the pylorus down, has, covering its- internal surface, two classes of glands from which ex- udes a fluid, the chief function of which is supposed to be to lubricate the inner surface. These glands are called Brunner's glands, occupying the upper portion of the duo- denum, and Lieberkiihn follicles, covering the rest of the intestine. In addition to these, the absorption of the digested food, which is the main office performed by the small intestine, is provided fgr by a special structure of its mucous mem- brane. The apparatus consists in an abundance of minute eminences or prolongations, the so-called villi of the small intestine, so closely set over its surface as to give it a char- acteristic velvety appearance. They are found throughout this part of the alimentary canal, from the pylorus to the free border of the ileo-csecal valve, most abundant in the duodenum and jejunum, rather less so in the ileum. The villi are the active agents in the process of absorp- tion ; there must be at least from fifteen to twenty millions of them in the intestine. By their abundance, as well as by thSir projecting form, they multiply the extent of con- tact of the digested fluids with the mucous membrane, and increase, in a corresponding degree, the activity of absorp- tion. They hang out into the nutritious, semi-fluid mass in the intestinal cavity,'as the roots of a tree penetrate the soil J and they imbibe its liquefied portions with a rapidity-! ANATOMY AND PHYSIOLOGY. 75 which is in proportion to their extent of surface and the movement of the circulation (XXX.). The final absorption of the digestive fluids is aecom- plished mainly by the blood-vessels of the intestinal villi. Their situation, their numbers, and the rapid movement of the blood are all favorable conditions for the performance of this function. The capillary plexus of each villus is situated, in its superficial part, immediately beneath the epithelial cells, so that the absorbed fluids, after passing through the epithelial layer, come at once in contact with the vascular network. The extension of absorbing surface, from the division and inosculation of these vessels, and the renovation of their fluids by the movement of the cir- culation, provide for their constant activity, Sind drain away the absorbed fluids from the interior of the villus as fast as they are taken up by its surface. The entrance of digested materials into the blood-ves- sels of the intestine has been demonstrated. After the digestion of food containing albuminous and starchy in- gredients, both glucose and peptone are met with in the blood of the portal vein. Emulsioned fatty matters may also be followed in their passage through the same chan- nels by the chylous aspect which they communicate to the portal blood. A variety of observers (Lehmann, Schultz, Simon), in examining the blood from different parts of the body, have also found the blood of the portal system con- siderably richer in fat than that of the arteries or of other veins, particularly while digestion is going on. (This will be further treated in the chapter on the circulation of the blood.) • ^6 A COMPEND OF The absorption of digested materials, particularly of the fatty matters, is also accomplished by the lacteals of the small intestine. These vessels are part of the great lym- phatic system, which is distributed everywhere — in the in- teguments of the head, the parietes of the trunk, the limbs, and in the glands, muscles, and mucous membranes— ^ throughout the body. Originating in the tissues of these oi'gans, they pass from the periphery toward the centre, converging and uniting with each other like the veins, and. passing at various points through the lymj)hatic glands (XLIL, b, b, etc.; XLIV., k ; XLYL, b). The fluid generally contained in these vessels is the " lymph." It is a colorless or slightly-yellowish transpar- ent liquid, absorbed by the lymphatic vessels from the va- rious tissues, and containing, besides water and saline mat- ters, a small quantity of fibrin and albumin. The lymphatic vessels of the intestine originate in the villi as longitudinal spaces lined with flattened epithelial cells, becoming provided, after a short distance, with trans- parent elastic coats, like those of the capillary blood-ve|,7i sels. On emerging from the villi they become part of the lymphatic plexus, from which the main branches pass be- tween the layers of the mesentery, from the intestine toward the posterior part of the abdomen. In this part of their course they inosculate with each other by transverse branches, and pass through several range's of mesenteric glands, representing the lymphatic glands of the abdomi- nal cavity. Near the attached portion of the mesentery, on the right side of the abdomen, about the level of the second lumbar vertebra, they terminate in a sacular dila- ANATOMY AND PHYSIOLOGY. TJ tation, the " receptaculum chyli." Prom this point the thoracic duct passes upward through the chest, crossing obliquely from right to left, and terminating in the left subclavian vein at its junction with the jugular of the same side (XV., 17; XVI., 17, 45, 46, 51; XXXV.). When the work of absorption by the villi and lacteals is • completed, the remaining matter passes right-hand side .of the abdomen, through an orifice between two valvular folds called the Ileo-caecal valve, into a large sac called the Caecum, at the commencement of the colon, or large intes- tine. Below this orifice, attached to the Caecum and open- ing into it, is a narrow worm-shaped tube called the appen- dix vermiformis, which varies from three to six inches in length, about the diameter of a goose-quill. It is usually directed upward and inward behind the Caecum, coiled upon itself, and terminates in a blunt point. Its canal is small and communicates with the Caecum by an orifice which is sometimes guarded by an incomplete valve. The vital functions of this organ, if it have any, are not known; but it sometimes occurs that small portions of undigested solid matter, such as fruit seeds, become lodged in it and produce fatal results. These instances, however, are very rare. The large intestine, called the Colon, commencing at the Caecum, passes upward to the lower side of the liver, and then transversely to the left side beneath the liver and the stomach, and then downward to form the sigmoid flexure at the commencement of the rectum, thus forming an arch inclosing the small intestine. Its three divisions are called the ascending, transverse, and descending colon. The function of this organ is to absorb the superfluous 7^ A COI^PEND OP fluids from the remnants of the alimentary mass (XIII., XXIV.). The Peritoneum is a serous membrane, and, like all membranes of this class,' a shut sac. In the female, how- ever, it is not completely closed. It partially invests all the viscera contaijied in the abdominal and pelvic cavities, forming the visceral layer of the membrane; it is then re- flected upon the internal surface of the parietes of those cavities, forming the parietal layer. » The great omentum, covering the upper portion of the intestines, and the lesser omentum, containing the hepatic vessels and nerves, with the mesentery, are embraced in 'this serous membrane. The affection called peritonitis is a diseased condition of this membrane, and its intimate relation with the entire abdominal viscera necessarily induces general sympathy with its condition, and suggests serious results. Hernia, or Rupture, is produced by excessive pressure of the lower portion of the intestines on the thin muscular tissues of the abdomen, generally in the vicinity of the groin, by which a small opening is made in its walls, and a portion of the intestine, covered with peritoneum, which forms a sac, is forced through. This condition sometimes exists for a long time unnoticed without serious results; but if the hernial sac and its contents remain protrude^ and there is constriction of the muscular fibres at its neck, so that the passage through the intestine is closed, a speedy surgical operation is necessary or fatal results will soon follow. Such an operation requires great skill and thorough anatomical knowledge of the p^rts, as the hernia is gener- ANATOMY AND PHYSIOLOGY. - 7$ ally in close proximity to the iliac and femoral bloods vessel. EESPIEATION. The most constant phenomenon presented by living organisms, both animal and vegetable, is the absorption of oxygen. This substance, either in gaseous form as a con- stituent of the atmosphere, or dissolved in water or other liquids, is indispensably requisite for the manifestation of vital phenomena. Oxygen is diffused everywhere over the surface of the earth, forming rather more than one-fifth part of the volume of the atmosphere, and exists in solu- tion in greater or less abundance in the water springs, rivers, lakes, and seas. Animals and plants, accordingly, -whether living in the air or ia the water, are surrounded by media in which this substance is present. Even parasitic organisms inhabiting other living bodies, though not in immediate contact with oxygen, are supplied with nutri- tious fluids which have themselves been -exposed to its in- fluence. Respiration consists in the process by which oxy- gen penetrates the substance of living organisms, and the ■ changes which accompany or follow its introduction. (LXXXIII., LXXXIV., LXXXV.) The respiratory apparatus in man begins with the larynx (XV., 10, 11, 12), communicating through the glottis with the pharynx. Then follows the trachea, a membranous tube with carti- laginous rings, dividing into the right and left bronchi (XII., 13). These divide in turn into secondary and terti- ary bronchi; the subdivision continuing, and the bronchial tubes growing constantly smaller and more numerous. So A COMPEND OP* When finally reduced to a diameter of 0.012 of an inch, they are composed only of a thin membrane, lined with pavement epithelium, resting upon an elastic fibrous layer. They are then known as the " ultimate bronchial tubes." ■ Each ultimate bronchial tube terminates in a pyramidal- shaped islet of pulmonary tissue, about 0.08 of an inch in diameter, termed a " pulmonary lobule."' It consists of a vascular membrane in the form of a sac, the cavity of which is divided into secondary compartments by thin partitions projecting from its inner surface. These secondary cavi- ties are the "pulmonary vesicles." They have an average ' diameter of about 0.01 of an inch ; but owing to the disten- sibility and' elasticity of their walls, they are capable of di- lating to double or triple their former size and returning to their original dimensions when the distending force is removed. There is reason to believe that during life they alternately expand and retract, as the lungs are filled and emptied with the movements of respiration. Bach vesicle is surrounded by capillary blood-vessels, which penetrate its partition walls and are thus exposed on both sides to the influence of the air in the pulmonary cavities. The abundant elastic tissue in the walls of the vesicles and in the interlobular spaces gives to the lungs their property of resiliency. The pavement epithelium lining the ultimate bronchial tubes extends into the lobules and vesicles, forming a continuous investment of their in- ternal surface. The extensive involution of the respiratory membrane resulting from the multiplication of the bronchial tubes and vesicles in the lungs, increases in a high degree the ANATOMY AND PHYSIOLOGY. 8 1 activity of respiration; since the blood in the capillary vessels, distributed in thin layers over so large a surface, in immediate proximity to the air in the pulmonary cavi- ties, is placed under the most favorable conditions for rapid arterialization. THE THOEAX. The Thorax (XXXVIIL, XLII,) is a conical framework formed partly of bones and partly of the soft tissues by which they, are connected together. It is supported and its back part is formed by the middle or dorsal region of the spine. It is narrow above, broad below, 'flattened be- fore and behind, and somewhat cordiform in a transverse section. It is bounded in front by the sternum (XXXVIII., 31, 32, 33), the six upper costal cartilages, the ribs, and intercostal muscles; at the sides by the ribs and intercos- tal muscles; and behind by the same structures and the dorsal portions of the vertebral column. The superior opening of the thorax is bounded on each side by the first rib; in front by the upper border of the sternum; and behind by the first dorsal vertebra. It is broader from side to side than from before backward, and its direction is backward and upward. The lojoer opening or base is bounded in front by the en- siform fartilage; behind by the last dorsal vertebra; and on each side by the last rib, the diaphragm filling in the in- tervening space (XXXVIIL, 31, 32, 33). The parts which pass through the upper opening of the thorax are (X.), from before backward, the sterno-hyoid and sterno-thyroid muscles, the remains of the thymus 82 A COMPEND OF gland, the trachea, oesophagus, thoracic duct, and the lon- gus colli muscles of each side; on the sides the arteria in- nominata, the left common carotid and left subclavian ar- teries, the internal mammary and superior intercostal arteries, the right and left venfe innominatas and the infe- rior thyroid veins, the pneumogastric, sympathetic, phreijic,, and cardiac nerves, the anterior branch of the first dorsal nerve, and the recurrent laryngeal nerve of the left side. The apex of each lung, covered by the pleura, also projects through this aperture, a little above the margin of the first rib. The. viscera contained in the thorax are (X., 5, 6) the heart, inclosed in its membranous bag, the pericardium, ^and the lungs, invested by the pleura. OEGAlSrS OF EBSPIEATION. THE LAEYNX. (XII., f., LXXXIII., LXXXIV., LXXXV.) , The Larynx is the organ of voice, placed at the upper part of the air-passage. It is situated between the trachea and base of the tongue, at the upper forepart of the neck, vifhere it forms a considerable projection in the middle line. On either side of it lie the great vessels of the neck; behind it forms part of the boundary of the pharynx (XXXIII., 6, 8), and is covered by the mucous membrane lining the cavity. The Larynx is narrow and cylindrical below, but broad above, wh^re it, presents the form of a triangular box, flat- ANATOMY AND PHYSIOLOGY. 83 tened behind and at the sides, while in front it is bounded by a prominent vertical ridge. It is composed of cartilages, which are connected together by ligaments and moved by numerous muscles; the interior is lined by mucous mem- brane and supplied with vessels and nerves. The Cartilages of the larynx are nine in number, three single and three pairs, one Thyroid, Cricoid, and Epiglot- tis; and two each Arytenoid, Cornicula Laryngis, and Cu- neiform (LXXXIII.). The Thyroid (6) is the largest cartilage of the larynx. It consists of two lateral lamellee or alse, mnited at an acute angle in front, forming a vertical projection in the middle line which is prominent above, and called the pommn Adami. The Cricoid Cartilage (9) is so called from its resemblance I to a signet ring. It is smaller but thicker and stroriger than the thyroid cartilage, and forms the lower and back part of the cavity of the larynx. The Arytenoid Cartilages (LXXXV., 5). are so called from the resemblance they bear, when approximated, to the mouth of a pitcher. They are two in number, and situated at the upper border of the cricoid cartilage, at the back of the larynx. Each cartilage is pyramidal in form. The cuneiform cartilages are two small, elongated car- tilaginous bodies, placed one on each side, in the fold of mucous membrane which extends from the apex of the arytenoid cartilage to the side of the epiglottis. The epiglottis (1) is a thin lamella of fibro-o^j-tilage, of a yellowish color, shaped like a leaf, and placed behind the tongue in front of the superior opening of the larynx. 84 A COMPEND OF During respiration its direction is vertically upward, its free extremity curving forward toward the base of' the tongue; but when the larynx is drawn up beneath the base of the tongue, during deglutition, it is carried downward and backward, so as to completely close the opening of the larynx. Iljs free extremity is broad and rounded; its at- tached end is long and narrow, and connected to the reced- ing angle between the two alse of the thyroid cartilage, just , below the median notch, by a long, narrow, ligamentous band, the tliyro-epiglottic ligament. It is also connected ' to the posterior surface of the body of the hyoid bone by an elastic ligamentous band, the liyo-epiglottic ligafmnt (LXXXIV.). The epiglottis, cuneiform ca;rtilages, and cornicula laryn- gis are composed of yellow cartilage, which shows little tendency to ossification; but the other cartilages resem- ble in structure the costal cartilages, becoming more or less ossified in old age. The ligaments of the larynx are extrinsic, those connect- ,; ingthe thyroid cartilage with theos hyoides; and intrinsic, • those which connect the several cartilaginous segments to each other (LXXXIIL, LXXXV. contain external figures in full). The ligaments connecting the thyroid cartilage with the OS hyoides are three in number : the thyro-hyoid membrane and two lateral thyro-hyoid ligaments. The thyro-hyoid membrane is attached below to the upper border of the thyroid cartilage, and above to tlie upper bor- der of the inner surface of the hyoid bone. In the middle it is pierced by the superior laryngeal vessels and nerve. » ANATOMY AND PHYSIOLOGY. 85 The two lateral thyro-hyoid ligaments pass between the superior cornua of the thyroid cartilage and the extremi- ties of the greater cornua of the hyoid bone. . ^ The crico-thyroid viembrane connects together the con- tiguous margins of the thyroid and cricoid cartilages, and extends from the superior border of the cricoid cartilage to the inferior margin of the true vocal cords, with which it is closely united in front. A capsular ligament incloses the articulation of the in- ferior cornu of the thyroid with the cricoid cartilage on each side. The hyo-epiglottic ligament extends from the anterior surface of the epiglottis, near its apex, to the posterior' surface of the body of the hyoid bone. The thy ro-epi glottic ligament connects the apex bf the epiglottis with the receding angle of the thyroid cartilage, immediately beneath the median notch, above the attach- ment of the vocal cords. Interior of the Larynx (LXXXIV.), The superior aper- ture of the larynx is a triangular or cordiform opening, wide in front, narrow behind, and sloping obliquely down- ward and backward. It is bounded in front by the epiglot- tis; behind by the apices of the arytenoid cartilages and the cornicula laryngis; and laterally by a fold of mucous membrane, inclosing ligamentous and muscular fibres, stretched between the sides ef the epiglottis and the apex of the arytenoid cartilages; these are the aryteno-epiglotti- dean folds, on the margins of which the cuneiform carti- lages form a more or less distinct' whitish prominence. The cavity of the larynx extends from the aperture be- 86 A COMPEND OF hind the epiglottis to the lower border of the cricoid car- tilage. It is divided into two parts by the projection inward of the vocal cords and the thyro-arytenoid muscles; between the two cords is a long, narrow triangular fissure or chink, theglottis or rima glottidis. The portion of the cavity of the larynx- atiove the glottis is broad and triangular in shape above, and corresponds to the int6rval between the alee of the thyroid cartilage ; the portion below the glottis is at first of an elliptical, and lower down of a circular form. The glottis is the interval between the inferior or true vocal cotds. The two superior or false vocal cords are placed above the latter, and are formed almost entirely by a folding inward of the mucous membrane; while the two inferior or true vocal cords are thick, strong, and formed partly by mucous membrane and partly by liga- mentous fibres. Between the true and false vocal cords, on each side, is an oval depression, the sinus, or ventricle of the larynx, which leads upward on the outer side of the superior vocal cord, into a csecal pouch of variable size, the sacculus laryngis. 'Yhe glottis {rima glottidis) is a narrow fissure. or chink between the inferior or true vocal cords. It is the narrow- est part of the cavity of the larynx, and corresponds to the lower level of the arytenoid cartilages. Its length in the male measures rather less than an inch, its breadth when dilated varying at its widest part from a third to half an inch. In the female these measurements are somewhat less. The form of the glottis A'aries. In its half-closed condition it is a narrow fissure, a little enlarged and ANATOMY AND PHYSIOLOGY. 8/ rounded behind. In quiet breathing it is widely open, somewhat triangular, the base of the triangle directed backward, and corresponding to the space between the sep- arafed arytenoid cartilages. In forcible expiration it is smaller than during inspiration. When sound is produced it is more narrowed, the margins of the arytenoid carti- lages being brought into contact, and the edges of the vocal cords approximated and made parallel, the degree of ap- proximation and tension corresponding to the height of the note produced. The superior or false vocal cords, so called because they are not directly concerned in the production of the voice, are two folds of mucous membrane, inclosing a delicate, narrow fibrous band, the superior thyr a- arytenoid ligament. This ligament consists of a thin band of elastic tissue, attached in front to the angle of the thyroid cartilage be- low the epiglottis, and behind to the anterior surface of the arytenoid cartilage. The lower border of this ligament, inclosed in mucous membrane, forms a free crescentic margin, which constitutes the upper boundary of the ventri- cle of the larynx. The inferior or true vocal cords, so called from their be- ing concerned in the production of sound, are two strong fibrous bands {inferior thyro-arytenoid ligaments) covered on their surface by a thin layer of mucous membrane. Each' ligament consists of a band of yellow elastic tissuu, attached in front to the depression between the two alae of the thyroid cartilage, and behind to the anterior angle of the base of the arytenoid. Its lower border is continuous with the thin lateral part of the crico- thyroid membrane. 88 A COMPEND OF Its upper bordei; forms the lower boundary of the ventricle of the larynx. Externally, the Thyro-arytsenoideus mus- cle lies parallel witli it. ' It is covered internally by mucous membrane, which is extremely thin and closely adherent to its surface. The ventricle of the larynx is an oblong fossa, situated between the superior and inferior vocal cords on each side, and extending nearly their entire length. This fossa is bounded above by the free crescentic edge of the superior vocal cord; below by the straight margin of the true vocal cordj externally by the corresponding Thyro-arytsenoideus muscle. The anterior part of the ventricle leads up by a narrow opening into a caecal pouch of mucous membrane of variable size, called the laryngeal pouch. The sacculus laryngis, or laryngeal pouch, is a membra- nous sac placed between the superior vocal cord and the inner surface of the thyroid cartilage, occasionally extend- ing as far as its upper border; it is conical in form and curved slightly backward, like a Phrygian cap. On the surface of its mucous membrane are the openings of sixty or seventy small follicular glands, which are lodged in the submucous areolar tissue. This sac is inclosed in a fibrous capsule continuous below with the superior thyro-arytenoid ligament; its laryngeal surface is covered by the Arytseno- epiglottideus inferior muscle {^Compressor sacculi laryngis), while its exterior is covered by the Thyro-epiglottideus muscle. These muscles compress the sacculus laryngis, and discharge the secretion it contains upon the chordae vocales, the surface of which it is intended to lubricate. Muscles. The intrinsic muscles of the larynx are eight.' ANATOIV^Y AND PHYSIOLOGY. 89 in number, five of which are the muscles of the chord^ vocales and rima glottidis; three are connected with the epiglottis. The five muscles of the chordse vocales and rima glottidis ■are the Crico-thyroid, Crico-arytsnoideus posticus, Crico- arytaenoideus lateralis, Arytsenoideus, and Thyro-arytsenoi- deus. The muscles of the epiglottis are the Thyro-epiglottideus and Arytseno-epiglottideus, superior and inferior. The muscles that open the glottis are the Crico-arytae- noid,ei postici, and those which close it are the ArytEenoi- deus and the Crico-arytaenoidei laterales. The muscles which regulate the tension of the vocal cords are the Crico- thyroidei, which stretch and elongate them, and the Thyro- arytaenoidei, wliich relax and shorten them. The Thyro- epiglottideus is a depressor of the epiglottis, and the Arytseno-epiglottei constrict the superior aperture of the larynx, compress the sacculi laryngis, and empty them of their contents. I'he Mucous Membrane of the larynx is continuous above with that lining the mouth and the pharynx, and is pro- longed through the trachea and bronchi into the lungs. It lines both surfaces of the epiglottis, to which it is closely adherent, and forms the aryteno-epiglottidean folds which encircle the superior aperture of the larynx. It lines the whole of the cavity of the laryn:^ ; forms, by its reduplica- tion, the chief part of the superior, or false, vocal cord; and from the ventricle is continued into the sacculus laryngis. It is then reflected over the true vocal cords, where it is thin and very intimately adherent; covers the 90 A COMPEND OF in,ner surface of the crico-thyroid membrane and cricoid cartilage, and is ultimately continuous with the lining membrane of the trachea. It is covered with columnar .ciliated epithelium below the superior vocal cord; but above this point the cilia are found only in front, as high as the middle of the epiglottis. In the rest of its extent ^ the epithelium is of the squamous variety. Glands. The mucous membrane of the larynx is fur- nished with numerous muciparous glands. The orifices are found ill nearly every part ; they are very numerous upon the epiglottis, being lodged in little pits in its substance; they are also found in large numbers along the posterior margin of the aryteno-epiglottidean fold, in front of the arytenoid cartilages, where they are termed the arytenoid glands. They exist also in large numbers upon the inner surface, of the sacculus laryngis. None is found on the. vocal cords. Vessels and Neeves. The arteries of the larynx are the laryngeal branches derived from the superior and in- ferior thyroid. The veins empty themselves into the su- perior, middle, and inferior thyroid veins. The lymphatics terminate in the deep cervical glands. The nerves are the superior laryngeal and the inferior or recurrent laryngeal branches of the pneumogastric nerves, joined by filaments from the sympathetic. The superior laryngeal nerves sup- ply the mucous membrane of the larynx and the Crico- thyroid muscles. The inferior laryngeal nerves supply the remaining muscles. The Arytenoid muscle is supplied by . both nerves. * ANATOMY AND PHYSIOLOGY. 9I THE TEAOHBA. (XII., g.) The Trachea or windpipe is a cartilaginous and membra- nous cylindrical tube, flattened posteriorly, which extends from the lower part of the larynx, on a level with the fifth cervical vertebra, to opposite the third dorsal, where it di- vides into the two bronchi (13), one for each lung. The trachea measures about four inches and a half in length; its diameter from side to side is from three-quarters of an inch to an inch, being always greater in the male than in the female. The anterior surface of the trachea is convex, and cov- ered in the neck, from above downward, by the isthmus of the thyroid gland, the inferior thyroid veins, the arteria thyroidea jma, the sterno-hyoid and sterno-thyroid' muscles, the cervical fascia (in the interval betweenJ;hose muscles), and, more superficially, by the anastomosing branches be- tween the anterior jugular veins; in the thorax it is cov- ered from before backward by the first piece of the sternum, the remains of the thymus gland, the arch of the aorta, the innominate and left carotid arteries, and the deep car- diac plexus. It lies upon the oesophagus, which is directed to the left near the arch of the aorta ; laterally, in the neck, it is in relation with the common carotid arteries, the lateral lobes of the thyroid gland, the inferior thyroid ar- teries, and recurrent laryngeal nerves; and in the thorax it lies in the interspace between the pleurse, having the pneumogastric nerve on each side of it. 92 A COMPEND OF The Right Bronchus, wider, shorter, and more horizon- tal in direction than the left, is about an inch in length, and enters the right lung, opposite the fourth dorsal ver- tebra. The vena azygos arches over it from behind, and the right pulmonary artery Ifes below and then in front of it. The L&ft Bronchus is smaller, more oblique, and longer than the right, being nearly two inches in length. It enters the root of the left lung, opposite the fifth dorsal vertebra, about an inch lower than the right bronchus. It crosses, in front of the oesophagus, the thoracic duct and the descending aorta, passes beneath the arch of the aorta, and has the left pulmonary artery lying at first above and then in front of it. If a transverse section is made across the trachea a short distance, above its point of bifurcation and a bird's-eye view taken of its interior, the septum placed at the bottom of the trachea and sepa- rating the two bronchi will be seen to occupy the left of the median line, so that any solid body dropping into the trachea would naturally be directed toward the right bron- chus, and this tendency is undoubtedly aided by the larger size of this -tube, as compared with its fellow. This fact serves to explain why a foreign substance in the trachea generally falls into the right bronchus. The trachea is composed of imperfect cartilaginous rings, ■fibrous membrane, muscular fibres, mucous membrane, and glands. The Cartilages vary from sixteen to twenty in number j each forms an imperfect ring, which surrounds about two- thirds of the cylinder of the trachea, being imperfect be- ANATOMY AND PHYSIOLOGY. 93 hind, where the tube is completed by fibrous membrane.. The cartilages are placed horizontally above each other, separated by narrow membranous intervals. Vessels and Nerves. The trachea is supplied with blood by the inferior thyroid arteries. The veins terminate in the thyroid venous plexus. The nerves are derived from the pneumogastric and its recurrent branches and from the sympathetic. THE PLEUE^. Each lung is invested, upon its ext.ernal surface, by a delicate serous membrane, the Pleura, which incloses the organ as far as its root, and is then reflected upon the in- ner surface of the thorax. The portion investing the sur- face of the lung is called the pleura pulpionalis, while that which lines the inner surface of the chest is called the pleura costalis. The interspace or cavity between these two layers is called the cavity of the pleura. Each pleura is therefore a shut sac, one occupying the rjght, the other the left half of the thorax; and they are perfectly separate, not communicating with each other. The two pleurae do not meet in the middle line of the chest, excepting at one point in front, an interspace being left between them which contains all the viscera of the thorax except the lungs; this is the mediastinum. - Commencing at the sternum, the pleura passes outward, covers the costal cartilages, the inner surface of the ribs and intercostal muscles, and at the back part of the thorax passes over the thoracic ganglia and their branches, and is reflected upon the sides of the bodies of the vertebrae. 94 A COMPEND OF where it is separated by a narrow interspace, the posterior mediastinum, fro In the opposite, pleura. From the verte- bral column the pleura passes to the side of the pericar- dium, which it covers to a slight extent; it then covers the back part of the root of the lung, from the lower bor- der of which a triangular fold descends vertically by the side of the posterior mediastinum to the Diaphragm. This fold is the broad ligament of the lung, the hgamentum , latum pulmonis, and serves to retain the lower part of that organ in position. From the root the pleura may be traced over the convex surface of the lung, the summit and base, and also over the sides of the fissures between the lobes. It covers its anterior surface and the front part of its root, and is reflected upon the side of the pericardium to the inner surface of the sternum. Below, it covers the surface of the Diaphragm. Above, its apex projects> in the form of a, cul-de;,saG, through the superior opening of the thorax, into , the neck, extending about an inch above the margin of the first rib, and receives the summit of the corresponding lung; this sac is strengthened by a dome-like expansion of, fascia, derived from the lower pajt of the Scaleni muscles (LXXXVIII. The dark line is the cavity of the pleurae). A little above the middle of the sternum, the contiguous' ^ surfaces of the two pleura are sometimes in contact for a slight extent; but above and below this point the interval left between them forms the anterior mediastinum. The inner surface of the pleura is smooth, polished, and moistened by a serous fluid; its outer surface is adherent to the surface of the lung and to the pulmonary vessel? as they emerge from the pericardium; it is also adherent ANATOMY AND PHYSIOLOGY, 95 to the upper surface of the Diaphragm ; throughout the rest of its extent it is somewhat thicker, and may be sepa- rated from the adjacent parts with great facility. Vessels and Nerves. The arteries of the pleura are de- rived from the intercostal, the internal mammary, the phrenic, inferior thyroid, thymus, pericardiac, and bron- chial. The veins correspond to the arteries. The lympha- tics are very numerous. The nerves are derived from the phrenic and sympathetic. MEDIASTINUM. The Mediastinum is the space left in the median line of the chest by the non-approximation of the two pleurae. It extends from the sternum in front to the spine behind, and contains all the viscera of the thorax, excepting the lungs. It is subdivided, for convenience of description, into the anterior, middle, and posterior. THE LUNGS. (X., 5; XII.) ^ The Lungs are the essential organs of respiration; they are two in number, placed one in each of the lateral cavi- ties of the chest, separated from each other by the heart and other contents of the mediastinum. Each lung is coni- cal in shape and the apex forms a tapering cone, which extends into the root of the neck a little above the level of the first rib. The base is broad, concave, and rests upon the convex surface of the Diaphragm (XVI., 27). The ex- .96 A"COMPEND OF ■ ' * , ». ternai or thoracib surface is smooth, convex, and corre- sponds to the form of t^e cayity of the chest, being deeper' ..behind than in front. The inn^r surface is concave. It presents in front a depression corresponding to the conj vex surface of bhepericardium, and behind, a deep fissure^ (the hilutn pulmonis) which , 'gives attachment to the root- of'^the lung. The posterior border istounded and broad, and is received in the deep concavity on either side of the sptnail column. It is much longer than the antd'ior bor- der, and projects below between^he ribs and the diaphragm. The .anterior border is thin and "sharp and overlaps the front of th« pericardium. cEachlripg is divided into two lobes, an upper and lower, by a'lon^ and deep fissure, which extends from the upper part of the pos|erior border of ' the organ, , about three inches fropa its.apex, downward and forward to the lower par^ of jts anterior border. ' This fissure penetrates nearly to the TOO t. In the right lung the upper lobe, is partially divided by a second and shorter fissure, which" extends from the middle of the preceding, forward and upward, to the anferior margki of tlje;prgan, marking ofE a ,f mall triangu. lar portioft, the middle lobe; thus there are really three lobes to the right lung and hut two to the, left. jriie right lung is tjie larger; it is broader than theJeft,* owing, to, the inclination 'of the heart to the left side; it is ' algo, shorter by an inch, in consequence of A COMPEND OF threQ branches, the inferior thyroid, supra-scapular, and transversalis colli. , The inferior thyroid passes upward in a serpentine course hehind the sheath of the common carotid vessel and sympathetic nerve, and is distributed to the under sur- face of the thyroid gland. Its branches are Laryngeal, dis- tributed to the back part, of the larynx; Tracheal, to the trachea; CEsophageal, to the oesophagus, and Ascend,ing cervical, to the vertebral column and the muscles of the iieck. The siiprorscapular artery passes obliquely from within outward, across the root of the neck, to the superior border of the scapula, where it passes over its transverse ligament to the supra-spinous fossa. It is mainly distributed to the supra-spinatus muscle, and sends branches to other adjacent muscles and to the shoulder-joint. 'The transversalis colli passes outward to the anterior margin of the trapezius muscle, beneath which it divides into two branches, the superficial cervical and the pos- terior Scapular. The superficial cervical supplies the Trapezius and neighboring muscles and glands. The posterior scapular sends branches to the Ehomboid, Latis- simus dorsi, and Trapezius muscles, anastomosing with the subscapular and the posterior branches of some of the in- tercostal arteries. .The Internal Mammary arises from the under surface of -the subcla.vian artery (XVII., 65) opposite the thyroid axis. It descends behind the clavicle to the inner surface of the anterior Wall of the chest, resting upon the costal car- tilages a short difitance from the margin of the sternum ANATOMY AND PHYSIOLOGY. I33 (XI., 1), and at the interval between the sixth and seventh cartilages divides into two branches, .the musculo-phrenic and superior epigastric. It is accompanied by two veins which join at the upper part of the thorax into a single trunk. The branches of this artery are : Superior Phrenic, which accompanies the phrenic nerve to the Diaphragm; Mediastinal branches which pass to the Mediastinum and the remains of the thymus gland; the pericardiac branches, to the pericardium and sternum; the anterior intercostal arteries, which inosculate with the intercostal arteries from the aorta; the perforating arteries, which supply the mam- mary glands ; the musculo-phrenic, to the intercostal spaces in a similar manner to the other intercostal artery, sending some branches to the diaphragm and abdominal muscles; and superior epigastric, distributed to the rectus muscle and anastomosing with the epigastric artery from the ex- ternal iliac. The superior intercostal artery arises from the upper and back part of the subclavian artery, behind the anterior scalenus on the right side and to the inner side of ; the muscle on the left. Passing backward it gives off the deep cervical branch, and then descends behind the pleura in front of the necks of the first two ribs, and inosculates with the first aortic intercostal; a branch goes to the pos- terior spinal muscles, and another to the spinal cord and its membranes. The deep cervical branch passes up the neck to the axis, supplying the muscles in its course. 134 A COMPEND OP THE AXILLA AND ITS AETBEY. The Axilla is^the name given to the space between the upper and lateral part of the chest and the inner side of the arm. It contains the axillary vessels and brachial plexus of nerves, with their branches, some branches of the intercostal nerves, and a large number of lymphatic glands, all connected together by. a quantity of fat and loose areolar tissue. The Axillary Artery (XVII., 68), the continuation of the subclavian, commences at the lower border of the first rib and terminates at the lower border of the tendons of the Latissimus dorsi and Teres major muscles, where it takes the name of brachial. The branches of this artery are: Supferior thoracic. Acromial thoracic, Thoyacica longa, Thoracica alaris, Subscapular, Anterior circumflex,- and Posterior circum- ' flex. These branches are distributed to all the muscles and integument of the axilla, from the deltoid and pectd- ralis (II., 30, 31) on the front to the tissues covering the scapula on the back (L., 7). The Brachial Artery (XVII., 69) commences at the lower margin of the tendon of the Teres major, and, pass- ing down the inner and anterior aspect of the arm, termi- nates about half an inch beloAV the bend of the elbow, where it divides into the radial and ulnar arteries (70, 71). Oc- casionally it is divided into two trunks for a short distance at its upper part, which are united above and below. The ^ point of bifurcation may be above or below the usual ANATOMY AND PHYSIOLOGY. 135 point, the JEormer condition being by far the most fre- quent. The divisions of the main arteries in the arm are variable in other respects also. The branches of the brachial artery are the Superior pro- funda, Nutrient artery, Inferior profunda, Anastomotica magna, and muscular. The most noted of these is the Anastomotica magna, 'by reason of its connection with the anastomosis around the elbow-joint. The Radial Artery (XVII., 71) commences at the bifur- cation of the brachial and passes along the radial side of the forearm to the wrist; it then winds back around the outer side of the carpus, beneath the extensor tendons of the thumb, and finally passes forward between the two heads of the first dorsal interosseous muscle into the palm of the hand, where it crosses the metacarpal bones to the ulnar border of the hand, to form the deep palmar arch (XVIIL, 4). At its termination it inosculates with the deep branch of the ulnar artery. This artery is accom- panied by two vensB comites throughout its whole course. The branches of the radial are — in the forearm, Badial reouiTent, Muscular, Superfici'alis volae. Anterior carpal; in the wrist. Posterior carpal. Metacarpal, Dorsales poUicis, Dorsales indicis; and in the hand, Princeps poUicis, Radialis indicis. Perforating, and Interosseous. The Ulnar Artery (XVII., 70), the larger of the two sub- divisions of the brachial, commences a little below the bend of the elboAV and crosses the inner side of the forearm obliquely inward to the commencement of its lower hal;f; it then runs along its ulnar border to the wrist, crosses the annular ligament -on the radial side of the pisiform ,136 A COMPEND OF , . bone, and passes across the palm of the hand, forming the ^superficial palmar- arch (X VIII., 3), which sometimes ter- minates by inosculating with the superficialis volae. The branches of the ulnar are — in the forearm. Anterior Ulnar Eecurrent, Posterior Ulnar Eecurrent, Interosseous, (XVII., 73), and muscular; in the wrist. Anterior carpal and Posterior carpal; in the hand. Deep,. or communicat- ing, and Digital branches (XVIII., 3). The most im- portant are the interosseous with its two branches and the digital branches to the fingers arising from the deep ppJmar arch. THE DESCENDING AOETA. (XVI., 25.) The Descending Aorta is divided into two portions, the •thoracic and abdominal, in correspondence with the two great cavities of the trunk in which it is situated. The Thoracic Aorta commences at the lower border ol the fourth dorsal vertebra on the left side, and terminates at the aortic opening of the Diaphragm in front of the last dorsal vertebra. At its commencement it is situated on the left side of the spine; it approaches the median line as it descends, and at its termination lies directly in front of the column. It is contained in the back part of the posterior mediastinum. The oesophagus with its accom- panying nerves lies on the right side of the aorta above, in front of the artery, in the middle^ of its course; while at its lower part it is on the left side, on a plane anterior'- to it, ANATOMY AND PHYSIOLOGY. 137 The branches of the thoracic aorta are : The Pericardiac, a few small vessels, distributed to the pericardium; the Bronchial, two or three in number, dis- tributed to the bronchi, the lungs, the bronchial glands, . and the oesophagus; the oesophageal arteries, four or fiye in number, arising from the front-of the aorta, anastomos- ing with branches of the inferior thyroid and phrenic and gastric arteries to form a chain along the tube; the Pos- terior mediastinal, numerous small vessels supplying the glands and loose areolar tissue in the mediastinum, and the Intercostal arteries (XVI., 34), arising from the back part of the aorta, ten in number on each side, distributed to the greater portion of the intercostal spaces, each artery dividing in its course into two branches, anterior and pos- terior, and each trunk and its branches being accompanied by an intercostal nerve and a vein. The Abdominal Aorta commences at the aortic opening of the Diaphragm, in front of the body of the last dorsal vertebra, and descending a little to the left side of the ver- tebral column, terminates on the body of the fourth lum- bar vertebra, commonly a little to the, left of the middle line, where it divides into the two common iliac arteries (XVI., 52, 53). As it lies upon the bodies of the vertebrae, the curve which it describes is< convex forward, the great- est convexity being in front of the third lumbar vertebra, which is a little above and to the left side of the umbilicus. The branches of the Abdominal aorta are as follows: The Ccelic Axis, a short thick trunk, about half an inch in length, which arises from the aorta opposite the margin of the Diaphragm, and, passing nearly horizontally for- 138' A COMPEND OF ward, divides into three large branches, the gastric, hepatic (31), and S2Jlenic (33), occasionally giving off one of the phrenic arteries. The gastric is the principal artery to the stomach, some of it^ branches, however, anastomosing in their course with branches from the splenic and hepatic arteries. The hepatic ife the artery that supplies the liver; it sends s, pyloric branch to unite with the gastric, the Gastro-duodenalis, to distribute branches to the duodenum, •pylorus, and pancreas, and the cystic artery, which supplies the gall-bladder. The SjJlenic artery is remarkable for the tortuosity of its course. It passes horizontally to the left side behind the upper border of the pancreas, accom- panied by the splenic vein, which lies below it, and on arriving near the spleen divides into numerous branches, some of which enter the spleen to be distributed to the substance of that structure, while others are distributed to the great end of the stomach and the pancreas. The gastro-epiploica, the largest branch of the splenic, anastomosing with a similar branch of the hepatic, runs along the great curvature of the stomach, between the layers of the great •omentum. In its course it distributes branches to the stomach which ascend on both surfaces; others ascend to supply the omentum. : The Superior Mesenteric Artery (XVI., 43) supplies the whole length of the small intestine except the first part of the duodenum; it also supplies the csecum and ascending and transverfee colon; it is a vessel of large size, arising from the fore part of the aorta, about a quarter of an inch below the coelic axis, being covered at its origin by the splenic vein and pancreas. It passes forward between the, ANATOMY AND PHYSIOLOGY. 13$ pancreas and transverse portion of the duodenum, crosses in front of this portion of the intestine, and descends be- tween the layers of the mesentery to the right iliac fossa, where it terminates, considerably diminished in size. ,' In its course it forms an arch ; the convexity is directed for- ward and downward to the left side, the concavity back- ward and upward to the right. It is accompanied by the superior mesenteric vein (40) and is surrounded by the superior mesenteric plexus of nerves. The names of the branches of the superior mesenteric ■ artery are the Inferior pancreatico-duodenal, Vasa in- testini tenuis, Ileo-colic, Colica dextra, and Colica media. By these branches the distribution is made as above in- dicated. The distribution of the .vasa intestini tenuis, twelve or fifteen in number, to the convolutions of the jejunum and jleum, is accomplished by an intricate net- work or plexus from which minute branches are sent to all the parts. The Inferior Mesenteric Artery (XVI., 43) supplies the descending (XIII., 9) and sigmoid flexure of the colon and the greater part of the rectum (10). It arises from the left side of the aorta, between one and two inches above its di- vision into the common iliacs. It passes downward to the left iliac fossa, and then descends between the layers of the meso-rectum into the pelvis, under the name of the superior hemorrhoidal artery. Its branches are the Colica sinistra. Sigmoid, and Su- perior hemorrhoidal, by which its distribution is made as above indicated. The Renal Arteries (XVI., 48, 49) are two large trunks HO A COMPEND OF which arise from the sides of the aorta immediately below the superior mesenteric artery. Each is directed outward so as to form nearly a right angle with the aorta. The right is longer than the left on account of the position of the aorta; it passes behind the vena cava (26). The left is somewhat higher than the right. Previously to enter- ing the kidney each artery divides into four or five branches, which are distributed to its substance. At the hilum these branches lie between the renal vein and ureter, the vein being usually in front and the ureter be- hind. Each vessel gives off some small branches to the suprarenal capsliles (39), the ureter (44), and the surround- ing membrane and muscles. The Phrenic Arteries are two small vessels which pre- sent much variety in their origin. They may arise sepa- rately from the front of the aorta, immediately below the coelic axis, or by a, common trunk, which may spring either from the aorta or the ccelic axis. Sometimes one is de- . rived from the aorta and the other from one of the renal arteries. Their general distribution is to the diaphragm, but branches pass also to the inferior vena cava, the CBSophagus, suprarenal capsules, spleen, and liver. The Ltimhar Arteries are analogous to the intercostals. They are usually four in number on each side and arise from the back part of the aorta, nearly at right angles with that vessel-. They pass outward and backward, around the sides of the body of the corresponding lumbar vertebra, behind the sympathetic veins and psoas muscle; those on the right side being covered by the inferior vena cava, and the two upper ones on each side by the crura of ANATOMY AND PHYSIOLOGY. I4I the Diaphragm, In the interval between the transverse processes of the vertebrae each artery divides into a dorsal and an abdominal branch. The dorsal branch is distrib- uted to the muscles and integument of the back, anasto- mosing with each other and with the intercostals; it also sends a branch to the spinal canal. The abdominal branches pass outward behind the Quadratus lumborum muscle, the lowest branch occasion- ally in front of that muscle, and being continued between the abdominal muscles, anastomose with branches of the epigastric and internal mammary in front, the intercostals above, and those of the ileo-lumbar and circumflex- iliac below. The Middle Sacral Artery is a small vessel which arises from the back part of the aorta, just at its bifurcation. It descends upon the last lumbar vertebra and along the middle line of the front of the sacrum to the upper part of the coccyx, and is distributed to the adjacent parts. COMMON ILIAC ARTERIES. (XVI., 53, 53.) The, abdominal aorta divides into the two Common Iliac arteries. The bifurcation usually takes place on the left side 0^ the body of the fourth lumbar vertebra. This point corresponds to the left'side of the umbilicus, and is on a level with a line drawn from the highest point of one iliac crest to the other (XLIII., 0). They are about two inches in length; diverging from the termination of 14^ A COMPEND OF the aorta, they pass downward and outward to the margin of' the pelvis, and divide opposite' the intervertebral sub- stance, between the last lumbar vertebra and the sacrum, into two branches, the external (XVI., 57) and internal iliac (56) arteries; the former supplying the lower ex- tremity and the latter the viscera and parietes of the pelvis. The common iliac arteries give off small branches to the peritoneum, psoas muscles, ureters, and the surrounding cellular membrane, and occasionally give origin to the ileo- lumbar or renal arteries. INTERNAL ILIAC AETEEY. (XVI., 56.) The Internal Iliac Artery supplies the walls and viscera of the pelvis and inner side of the thigh. It is a short thick vessel, smaller than the external iliac, and about an inch and a half in length, which arises at the point of bifurcation of the common iliac, and passing downward to the upper margin of the great sacro-sciatic foramen, divides into two large trunks, an anterior and posterior. Its anterior trunk has nine branches, its posterior trunk has three. The Obturator Artery iisually arises from the anterior trunk of the internal iliac, frequently from the posterior. It passes down through the obturator foramen, and divides into an external and an intern&l branch. After sending off a vesical and a pubic branch before leaving the cavity of the pelvis, its external branch distributes to the obtura- tor, Pectineus, Adductor, and Gracilis muscles. The ex- ANATOMY AND PHYSIOLOGY. 143 ternal branch supplies the Obturator Muscles and sends branches to the hip-joint. The Sciatic Artery, the larger of the two terminal branches of the anterior trunk of the internal iliac, is dis- tributed to the muscles on the back of the pelvis. It passes down to the lower part of the great sacro-sciatic foramen, resting on the sacral plexus of nerves and Pyri- formis muscle, and escapes from the pelvis betw"een the Pyriformis and Coccygeus. It then descends in the "in- terval between the trochanter major and tuberosity of the ischium, accompanied by the sciatic nerves and covered by the Gluteus maximus, and divides into branches which supply the deep muscles of the back of the hip. The Gluteal Artery is the largest branch of the internal iliac, and appears to be the continuation of the posterior division of that vessel. It passes out of the pelvis above the upper border of the Pyriformis muscle, and immedi- ately divides into a superficial and deep branch. Within the pelvis it gives ofE a few muscular branches' to the Iliacus, Pyriformis, and Obturator iiiternus, and just pre- vious to quitting that cavity a nutrient artery which en- ters the ileum. EXTEKNAL ILIAC AETIIEY. ~ (XVI., 57.) The External Iliac is the chief vessel that supplies the lower limb. It passes obliquely downTard and outward along the inner border of the Psoas muscle, from ±he bifur- cation of the common iliac to the femoral arch, where it 144; A compend of enters the thigh and becomes the femoral artery. The course of this vessel would be indicated by a line drawn from the left side of the umbilicus to a point midway be- tween the anterior superior spinous process of the ileum and the symphysis pubis. Besides several small branches to the Psoas muscles and the neighboring lymphatic glands, the external iliac gives off two branches of considerable size, the Epigastric and Circumflex iliac. Tlie Epigastric artery arises from the external iliac a little above Poupart's ligament, and after descending to that ligament ascends beneath and distributes branches to the Eectus muscle, and above the umbilicus anastomoses with the internal mammary and intercostal arteries. It is accompanied by two veins, which usually unite into a single trunk before their termination in the external iliac vein. The Circumflex Iliac Artery arises from the outer side of the external iliac nearly opposite the epigastric, and as- cends obliquely outward behind Poupart's ligament, and anastomoses with the ileo-lumbar and gluteal arteries. This artery also is accompanied by two veins which unite in a single trunk which enters the external iliac vein. FEMOKAL ARTEEY. I (XVI., 60; XIX., 1.) The Femoral Artery is the continuation of the external iliac. It commences immediately behind Poupart's liga- ment, midway between the anterior superior spinaxif the ANATOMY AND PHYSIOLOGY. I4S ilium and the symphysis pubis, and passing down the fore part and inner side of the thigh, terminates at the open- ing in the Adductor magnus, at the junction of the middle with the lower third of the thigh (XIX., 2), where it be- comes the popliteal artery. A line drawn from a point mid- way between the anterior superior spine of the ilium and the symphysis pubis to tlie inner side of the inner condyle of the femur will be nearly parallel with the course of the artery. ' The branches of the femoral artery are the Superficial epigastric, Superficial circumflex iliac. Superficial external pubic, Profunda femoris. Muscular, and Anastomotica magna. The Profxmda Femoris (XVI., 62) nearly equals in size the Femoral, from which it arises. It issues from the outer and back part of the femoral artery, one or two inches below Poupart's ligament. It at first lies on the outer side of the -femoral, and then passes behind it and the femoral vein to the inner side of the femur, and terminates at the lower third of the thigh in a small branch, which pierces the Adductor magnus to be distributed to the flexor muscles on the back of the thigh, anastomosing with branches of the popliteal and inferior perforating arteries (XIX., 10). The profunda femoris sends out several branches: !Ex- ternal circumflex, Internal circumflex, and Perforating; supplying the anterior and posterior muscles of the thigh. 146 A COMPEND OF POPLITEAL AETEEY. The Popliteal Artery (XIX., 3, 3, 4) commences at tlie termination of the femoral at the opening in the Adductor magnus (V., 48), and passing obliquely downward and out- ward behind the knee-joint to the lower border of the popliteus muscle, divides into the anterior and posterior ■ tibial arteries (XXXVII., 3). The region of the limb trav- ersed by this artery is called the Poplilteal Space. The artery iA its course downward to the lower border of the popliteus muscle rests first on the inner and then on the posterior surface of the femur; in the middle of its course, on the posterior ligament of the knee-joint; and below, on the fascia covering 'the popliteus muscle. The f)opliteal vein, which is intimately attached to the artery, ies superficial and external to it, until near its termina- tion, when it crosses it and lies on its inner side. In its course the popliteal artery sends out the following branches : Superior and Inferior muscular. Cutaneous, External and Internal Superior articular, Azygos articular, and External and Internal Inferior articular. These distribute filaments to the muscles of the popliteal space, to the knee-joint, and some to the integument of the calf. AISTTBEIOE TIBIAL AETEEY. (XIX., 5.) HhQ Anterior Tibial Artery commences at the bifurca- tion of the popliteal, at the lower border of the popliteus muscle, passes forward between the two heads of the Tibia- ANATOMY AND tMVSlOLOGY. 14/ lis posticus, and through the aperture left between the bones at the upper part of the interosseous menlbrane, to the deep part of the front of the leg; it then descends on the anterior surface of the interosseous membrane and of the tibia to the front of the ankle-joint, where it lies more superficially and becomes the dorsalis pedis. The anterior tibial artery is accompanied by two veins land the anterior tibial nerve. The branches of this artery are Ke- current tibial. Muscular, and Internal and External mal- leolar. The two former supply the musctes on the front of the leg and the latter the ankle-joint. DOKSALIS PEDIS AKTEEY. The Dorsalis Pedis, the continuation of the anterior tibial, passes forward from the bend of the ankle along the tibial side of the foot to the back part of the first inter- osseous space, where it divides into two branches, the dor- salis hallucis and communicating. It is accompanied by two veins. It has also Tarsal, Metatarsal, and Interosseous branches, and all its branches are distributed to the ankle and foot, some of them extending to the toes. POSTEEIOR TIBIAL ARTERY. (XIX., 8.) The Posterior Tibial is an artery of large size, which ex- tends obliquely downward from the lower border of the popliteus muscle, along the tibial side of the leg, to the fossa between the inner ankle and the heel, where it divides . 148 ' A cOmpenE) op beneath the origin of the Abductor pollicis, into the inter- nal and external plantar arteries. At its origin it lies op- posite the interval between the tibia and fibula; as it descends, it approaches the inner side of the leg, lying behind 'the tibia, and in the lower part of its course is sit- uated midway between the inner malleolus and the tuber- osity of the OS calcis. Its branches are Peroneal, Anterior Peroneal, Muscular, Nutrient, Communicating, and Inter- nal Calcanean. The Peroneal Artery (XIX., 9) lies deeply seated along the back part of the fibular side of the leg. It arises from the posterior tibial, about an inch below the lower border of the Popliteus muscle, passes obliquely outward to the fibula, and then descends along the inner border of that bone to the lower third of the leg, where it gives ofE the anterior peroneal. It then passes across the articulation between the tibia and fibula, to the outer side of the os calcis, supplying the neighboring muscles and back of the ankle, and anastomosing with the external malleolar, tarsal, and external plantar arteries. The Anterior Peroneal pierces the interosseous mem- brane, about two inches above the outer malleolus, to reach the fore part of the leg, and passing down beneath the Peroneus tertius, to the outer ankle, ramifies on the front and outer side of the tarsus, anastomosing with the exter- nal malleolar and tarsal arteries. The Internal Plantar, one of the terminal branches of the posterior tibial artery, arising between the inner ankle and the heel, passes forward along the inner side of the foot. At the base of the first metatarsal bone, it passes ANA;rOMY AND PHYSIOLOGY. 149 along the inner border of the great toe, inosculating. with its digital branches. The External Plantar passes obliquely outward and forward to the base of the fifth metatarsal bone. It then turns obliquely inward to the interval between the bases of the first and second metatarsal bones; where it anastomoses with the communicating branch from the dorsalis pedis artery, thus completing the plantar arch. The Plantar Arch (XIX.), besides distributing numer- ous branches to the muscles, integument, and fascise in the sole, gives off the following branches : Posterior perforating, and Digital — Anterior perforating, distributing branches to the toes. OF THE VEINS. The Veins are the vessels which serve to return the blood from the capillaries of the different parts of the body to the heart. They consist of two distinct sets of vessels, the pulmonary and systemic. The Pulmonary Veins contain arterial blood, which they return from the lungs to the left auricle of the heart. The Systemic Veins return the venous blood from the body generally to the right auricle of the heart. The Portal Vein, an appendage of the systemic venous system, is confined to the abdominal cavity, returning the venous blqpd from the viscera of digestion, and carrying it to the liver to be diffused through this organ and to be trans- mitted by the hepatic veins to the vena cava. The veins, like' the arteries, are found in nearly every tisgue pf the body. ISO A COMPEND OF They commence by minute plexuses, which communicate with the capillaries. The branches which coriimence in these plexuses unite together into trunks, and these, in their passage toward the heart,'constantly increase in size as they receive branches and join other veins similar in size to themselves. The veins are larger and altogether more numerous than the arteries ; hence the entire capac- ity of the venous system is much greater than that of the, ^rterial, the pulmonary veins excepted, which do not ex- ceed in capacity the pulmonary arteries. In form the veins are not perfectly cylindrical like the arteries, their walls being collapsed when empty and the uniformity of their surface being interrupted at intervals by slight con- tractions, which indicate the existence of valves in their interior. They usually retain, however, the same calibre as long as they receive no branches. ' The veins communicate very freely with each other, es- pecially in certain regions of the body; and this communi- cation exists between the larger trunks as well as between the smaller branches. Thus in the cavity of the cranium and between the veins of the neck, where obstruction would be attended with imminent danger to the cerebral venous system, we find that the sinuses and larger veins have large and very frequent anastomoses. The sarae free communication exists between the veins throughout the whole extent of the spinal canal, and between the veins composing the various venous plexuses in' th© abdomen and pelvis. The veins are subdivided into three sets: superficial, deep, and sinusesi ANATOMY AND PHYSIOLOGY. Ijl The Superficial or Gutaneonn Veins are found between the layers of superficial fascia, immediately beneath the integument; they return the blood from these structures, and communicate with the deep veins by perforating the deep fascia. There is a general uniformity in the main trunks of these veins, but in the anastomosing and dis- tribution of their branches there is great diversity, not only in different individuals, but also in the two sides of the same individual. The Deep FeiW accompany the. arteries and are usually inclosed in the same sheath with them. With the smaller , arteries, as the radial, ulnar, brachial, tibial, peroneal and their subdivisions, they exist generally in pairs, one lying , on each side of the vessel, and are called vense comites. The larger arteries, as the axillary, subclavian, popliteal, and femoral, have usually only one accompanying vein. In certain organs of the body, however, the deep veins do not accompany the arteries; for instance, the veins in-the skull and spinal canal, the hepatic veins in the liver, and the larger veins returning blood from the osseous tissue."' ■ Sinuses are venous channels which, in their structure and mode of distribution, differ altogether from the veins. They are found only on the interior of the skull, and are formed by a separation of the layers of the dura mater, their outer coat consisting of fibrous tissue, their inner of ^ a serous membrane continuous with the serous membrane of the veins. The veins may be arranged into four groups: 1. Those of the head and neck, upper extremity, and thorax, which terminate in the superior vena cava (XIT., 16). 2. Those 152 A COMPEND OF of the lower limb, pelvis and abdomen which terminate in the inferior vena cava (14). 3. The cardiac veins, which open directly into the right auricle of the heart (3). i. The pulmonary veins, which open into the left auricle (4). VEINS OF THE HEAD AND NECK., (XII.) The veins of the exterior of the head are Facial (25), Temporal (38), Internal maxillary, Temporo-maxilla,ryi ■ ,)• Posterior auricular, and Occipital (39). The veins of the neck are External Jugular (20), Posterior external jugu- lar, Anterior jugular (21), Internal jugular (19), and Ver- tebral (X., 3, 3, 4). There are numerous venous channels in the diploe be- tween the plates of the skull. The sinuses of the Dura Mater are venous channels sim- * ■'' ilar to the veins, and communicating with the large venous trunks in the neck. The External Jugular Vein (X., 3; XII., 30) receives the greater part of the blood from the exterior of the cra- nium and deep parts of the face, being a continuation of the temporo-maxillary and posterior auricular veins. K commences in the substance of the parotid gland (XXXI., 1), on a level with the angle of the lower jaw, and runs down the neck to about the middle of the clavicle (XI., 3), * and tBrminates in the subclavian vein (XX., 74), on the ' outer side of the internal "jugular (X., 3). This vein is occasionally double. It has two valves at its junction with ANATOMY AND PHYSIOLOGY. 153 the subclavian and two others about an inch and a half above the clavicle. The Internal Jugular Vein (X., 2; XII., 19) collects the blood from the interior of the cranium, from the superfi- cial parts of the face, and from the neck. It commences at the jugular foramen, in the base of the skull, being formed by the coalescence of the lateral and inferior pe- trosal sinuses. It runs down the side of the neck in a vertical direction, lying at first on the outer side of the internal carotid artery and then on the outer side of the common carotid, and at the root of the neck unites with the subclavian vein to form the vena innominata (XII., 17, 18). It has a pair of valv6s at its junction with the subclavian. This vein receives in its course the facial, lingual, pharyngeal, superior and middle thyroid veins, and^ some- times the occipital. At its point of junction with the branch common to the temporal and facial veins, it be- comes greatly increased in size (XII., 25). The common carotid artery, the internal jugular vein, and the pneumogastric nerve in the neck are united in one sheath. The Anterior Jugular Vein (XII., 21) collects the blood from the integument and muscles in' the middle of the anterior region of the neck. It passes down between the median line and the anterior border of the sterno-mastoid muscle, and at the lower part of the neck passes beneath that muscle to open into the termination of the external jugular or into the subclavian vein. Most frequently there are two of these veins, but occasionally only one. 1 54 A COMPEND OF Just above the sternum the two anterior jugular veins communicate by a transverse trunk, which receives branches' from the inferior thyroid veins. It also communicates with the internal and external jugular. There are no valves in this vein. The Cerebral Veins, very numerous, return the blood from the convolutions and substance of the cerebrum; they terminate in the sinuses by which the bloocf is passed to the jugulars. The Cerebellar Veins occupy the surface of the cerebel- lum; they terminate in the lateral sinuses. VEINS OF THE ARM AND HAND. (III., IV., XVII., XVIII.) The veins of the upper extremity are divided into two sets, "superficial and deep. The Superficial Veins are placed immediately beneath ' the integument, between the two layers of superficial fascia; they commence in the hand chiefly on its dorsal aspect, where they form a more or less complete arch. .' , The Deep Veins accompany the arteries and constitute the vense comites of those vessels. Both sets of vessels are provided with valves, which are more numerous in the deep than in the superficial. ' The, superficial veins of the upper extremity (III.) are the Anterior Ulnar (1), Posterior Ulnar (k). Basilic (j), E'adial (n). Cephalic (i). Median (m). Median basilic, and Median cephalic. ANATOMY AND PHYSIOLOGY. 1 55 The Anterior Ulnar Vein (I) commences on the anterior surface of the ulnar side of the hand and wrist, and as- cends along the inner side of the forearm to the bend of the elbow; here it joins with the posterior ulnar to form the basilic. It communicates with branches of the median vein in front and with the posterior ulnar behind. The Pgsterior Ulnar Vein (k) commences on the pos- terior surface of the ulnar side of the hand, and from the vein of the little finger. It runs on the posterior surface of the ulnar side of the forearm, and just below the elbow unites with the anterior ulnar vein to form the basilic. The Basilic (j) is formed by the coalescence of the an- terior and posterior ulnar veins. It is situated along the inner side of the elbow, receives the median basilic vein, and passing upward along the inner side of the arm pierces the deep fascia, and ascends in the course of the brachial artery, terminating either in one of the vense comites of that vessel or in the axillary vein. The Radial Vein (n) commences from the dorsal surface of the thumb, index finger, and radial side of the hand, and ascends along the radial side of the forearm, and re- ceives numerous branches from both its surfaces. At the bend of the elbow it receives the median cephalic, when it becomes the cephalic vein. The Cephalic Vein (i) courses along the outer border of the biceps muscle to the upper third of the arm; it then passes in the interval between the pectoralis major and Deltoid muscles, accompanied by the descending branch of the thoracico-acromialis artery and the up^er external cutaneous branch of the musculo-spiral nerve, and termi- 156 A COMPEND OF nates in the axillary vein, just below the clavicle. This vein is occasionally connected with the external jugular or subclavian, by a branch which passes upward in front of the clavicle. The Median Vein (m) collects the blood from the super- ficial structures on the palmar surface of the hand and middle line of the forearm, communicating with the an- terior ulnar and radiaL veins. At the bend of the ejbow it receives a branch of communication from the deep veins accompanying the brachial artery, and divides into two branches, the median cephalic and the median basilic, which diverge from each other as they ascend. The Median Cephalic passes outward and joins the ce- phalic vein. The Median Basilic Trasses inward and joins the basilic vein. The Beep Veins (XVIL) of the upper extremity follow the course of the arteries. They are generally two in number, one lying on each side of the corresponding artery, and they are connected at intervals by short transverse branches. These double vense comites commence in ■ the fingers, as there are two digital veins, accompanying each artery along the sides of the fingers; these, uniting at their base, pass along the interosseous spaces in the palm, and terminate in the two superficial palmar veins. Branches from these vessels on the radial side of the hand accom- pany the superficialis volae, and on the ulnar side terminate. , in the deep ulnar veins (70). The deep ulnar veins, as they pass in front of the wrist, communicate with the interos- seous and superficial veins, and unjtQ at the elbow with ANATOMY AND PHYSIOLOGY. 1$? the deep radial Teins, to form the^ vense comites of the brachial artery (69). The Interosseous Veins (73) are the veins accompanying the interosseous arteries. The Beep Palmar Veins accompany the deep palmar arch, being formed by branches which accompany the ram- ifications of that vessel. They communicate with the su- perficial palmar veins at the inner side of the hand, and on the outer side terminate in the vense comites of the radial artery (71). At the wrist they receive a dorsal and a palmar bramch from the thumb, and unite with the deep radial veins. Accompanying the radial artery, these ves- sels terminate in the venae comites of the brachial artery (69). The brachial veins are placed one on each side of the brachial artery, receiving branches corresponding with those given off from that vessel; at the lower margin of the axilla they unite with the basilic to form the axillary vein. The deep veins have numerous anastomoses, not only with each other, but also with the superficial veins. The Axillary Vein is of large size and formed by the continuation upward of the basilic vein. It commences, at the lower part of the axillary space, increases in size as it ascends by receiving branches corresponding with those of the axillary artery, and terminates immediately beneath the clavicle at the outer margin of the first rib, where it becomes the subclavian vein (66). It lies on the thoracic side of the axillary artery. Opposite the subscapularis it is joined by a large vein, formed by the junction of the IS8 . , A COMfEND. OF veiiEe comites of the brachial; and near its termination it receives the cephalic vein. This vein is provided with a pair of valves opposite the lower border of the subscapn- laris muscle; valves are also found at the termination of the cephalic and subscapular veins. The Subclavian Vein (XVII., 66), the continuation of the axillary, extends from the outer margin of the first rib to the inner end of the sterno-clavicular articulation, where it unites with the internal jugular (XII., 19), to form the vena innominata (17, 18). It is in front of the subclavian artery, and rests in a depression on the first rib. It is provided with valves about an inch from its ter- mination in the vena innominata, just external to the en- trance of the external jugular vein. The 'Vbn.S! iNKOMiNATiE are two large trunks, placed ' one on each side of the root of the neck, and formed by the union of theinternal jugular and subclavian veins of the corresponding side. The BigJit Vena Innominata (17) is about an inch and a half in length. It receives the right vertebral vein and right lymphatic duct, the right internal mammary, right inferior thyroid, and right superior intercostal veins. The Left Vena Innominata (18) is about three inches in length, and crosses obliquely from left to right across the upper and front part of the chest, to unite with its fellows, of the opposite side,. forming the superior vena cavd, (16). It lies in front of the three large arteries that arise from the arch of the aorta. This vessel is joined by the left , vertebral, left inferior thyroid, left internal mammary, and the, left superior . intercostal veins, and occasionally some ANATOMY AND PHYSIOLOGY. 1S9 thymic and pericardiac veins. There are no' valves in the venae innominatae. The Internal Mammary Veins, two in number to each artery, follow the course of that vessel. The Inferior Thyroid Veins arise in the venous plexus on the thyroid body (X., n), communicating with the mid- dle and superior thyroid veins. The Superior Intercostal Veins return the blood from the upper intercostal spaces. The Superior Vena Cava (XIL, 1G) receives the blood ' that is conveyed to the heart from the whole of the upper half of the body. It is two and a half or three inches in length, formed by the junction of the two venae innom- inataa. It enters the pericardium about an inch and a half above the heart and terminates in the upper part of the right auricle. The AzTGOS Veins (XVI.) connect together the supe- rior and inferior vente cavae, supplying the place of those vessels in the part of the chest occupied by the heart. , The Right Azygos (20) commences opposite the first or second lumbar vertebra, by a branch from the right lum- bar veins; sometimes by a branch from the renal vein, or from the inferior ven^ cava. It enters the thorax through the aortic opening in the Diaphragm, and passes along the right side of the vertebral column to the third ' dorsal ver- tebra, where it arches forward over the root of the right lung, and terminates in the superior vena cava, just before that vessel enters the pericardium. While passing through the abrtio opening of. the Diaphragm, it lies With the thoracic duct (17) on the right side of the aorta; and in l6o A COMPEND OF the thorax it lies upon the intercostal arteries, on the fight side of the aorta and thoracic duct, covered by the pleura. It receives nine or ten intercostal veins of the right side (24), the vena azygos minor (21), several oeso- phageal, mediastinal, and vertebral veins; near its termina- tion the right bronchial vein; and is occasionally connected with the right superior intercostal vein. This vein and its branches are provided with valves. The intercostal veins on the left side, below the two or three upper intercostal spaces, usually form two trunks, named the left lower and the left upper azygos veins. The left lower or smaller azygos vein commences by a branch from one of the lumbar veins, or from the left renal vein. It passes into the thorax, through the left crus of the Diaphragm, and ascending on the left side' of the spiije, as high as the sixth or seventh dorsal vertebra, passes across the column, behind the aorta and thoracic^' duct, to terminate in the right azygos vein. It receives the four or five lower intercostal veins of the left side and some oesophageal and mediastinal veins. The Left Upper Azygos Vein receives veins from the in- tercostal spaces between the left superior intercostal vein and the highest branch of the left lower azygos. They are usually two or three in number, and join to form a trunk, which ends in the right azygos vein or in the left lower azygos. Sometimes this vein is wanting, in which case the left superior intercostal vein will extend as low as the fifth or sixth intercostal space (23). ' The hronchial veins return the blood from the substance of the lungs; that of the right side opens into the vena ANATpMY AND PHYSIOLOGY. l6l azygps major, near its termination; that o'f the left side into the left superior intercostal vein. THE SPINAL VEINS. ^ The numerous venous plexuses placed, upon and within the spine may be arranged into four sets : 1. Those placed on the exterior of the spinal column {the dorsi-spinal veins). 2. Those in the interior of the spinal canal, between the vertebrae and the theca vertebralis (m'eningo-rachidean veins). 3. The veins of the bodies of the vertebrae. 4. The veins of the spinal cord (medulla-spinal). VEINS OE THE LOWER EXTEEMITY. (V.) The veins of the lower extremity are superficial and deep, the superficial veins, like those of the arm, being placed beneath the integument, between the two layers of superficial fascia; the deep veins accompanying the arteries and forming the venee comites of those vessels. Both sets of veins are provided with valves, which are more numer- ous in the deep than in the superficial set. They are also more numerous in the lower limb than the upper. The superficial veins of the lower extremity are thff internal or long saphenous vein and the external or short saphenous. There is the same want of uniformity in the anastomoses l62 A COMPEND OF and branches of these veins as in those of the upper ex- tremity. The Internal Saphenous, Vein (o) commences from a mi- nute plexus, which covers the dorsum and inner side of the foot; it ascends in front of the inner ankle and alon^ the' inner side of the leg, behind the inner margin of the tibia, accompanied by the internal saphenous nerve. At the knee it passes backward behind the inner condyle of the femhr, ascends along the inside of the thigh, and passing through the saphenous opening in the fascia lata, termi- nates in the femoral vein about an inch and a half below Poupa,rt's ligament. This vein receives in its course cuta- neous branches from the leg and thigh, and at the saphe- nous opening the superficial epigastric, superficial circum- flex iliac, and external pudic veins. The veins froip the inner and back part of the thigh frequently unite to form a large vessel, which enters the main trunk near the saphe- nous opening; and sometimes those on the outer side of the thigh join to form a large branch, so that occasionally three large veins are seen converging from different parts of the thigh toward the saphenous opening. The internal saphenous vein communicates in the foot with the internal plantar vein; in the leg, with the posterior tibial veins, and also with the anterior tibial veins ; at the knee, with the articular veins; in the thigh, with the femoral vein by one or more branches. The valves in this Vein vary from two to six in number; they are more numerous in the thigh than in the leg. The External or Sliort Saphenous Vein is formed by branches which collect the blood from the dorsum and ANATOMY AND PHYSIOLOGY. 163 outer side of the foot. It ascends behind the outer ankle, and along the outer border of the tendo Achillis, across which it passes at an acute angle to reach the middle line of the posterior aspect of the leg. Passing directly up- ward, it perforates the deep fascia in the lower part of the popliteal space, aud terminates in the popliteal vein, between the heads of the Gastrocnemius muscle. It re- ceives numerous large branches from the back of the leg, and communicates with the deep veins on the dorsum of the foot, and behind the outer malleolus. This vein has only two valves, one of which is always found, near its ter- mination in the popliteal vein. The Deep Veins of the lower extremity accompany the arteries and their branches, and are called the vencB comites of those vessels. The external and internal plantar veins unite to form the posterior tibial (XIX., 8). They accompany the posterior tibial artery, and are joined by the peroneal veins (9). The anterior tibial veins are formed by a continuation upward of the vense comites of the dorsalis pedis artery. They perforate the interosseous membrane at the upper part of the leg, and form, by their junction with the pos- terior tibial, the popliteal vein. The valves in the deep veins are very numerous. The Popliteal Vein (XIX., 13) is formed by the junction of the vense comites of the anterior and posterior tibial vessels; it ascends through the popliteal space to the ten- dinous aperture inthe Adductor magnus, where it becomes the femoral vein. In the lower part of its course it is 164; A COMPEND OF placed internal to the artery; between the heads of the Gastrocnemius (XXXVII., 1) it is close to its outer side. It receives the sural veins from the Gastrocnemius mus- cle, the articular veins, and the external saphenous. The valves of this vein are usually four in number. The Femoral Vein (XIX., 13) accompanies the femoral artery through the tipper two-thirds of the thigh. In the Ipwer part of its course it lies external to the artery; higher up it is iDehind It; and beneath Poupart's ligament it lies to its inner side and on the same plane. It receives nu- merous muscular branches; the profunda femoris joins it about an inch and a half below Poupart's ligament, and near its termination the internal saphenous vein (XVI., 61). The valves in this vein are four or five in number. The External Iliac Vein (XVI., 54) commences at the ter- mination of the femoral, beneath the crural arch, and pass- ing along the brim of the pelvis, terminates opposite the sacro-iliac symphysis by uniting with the internal iliac to form the common iliac vein. On the right side, ib lies at first along the inner side of the external iliac artery; tut as it passes upward, gradually inclines behind it. On the ■ left side, it lies altogether on the inner side of the artery. It receives, immediately above Poupart's ligament, the epi- gastric and circumflex iliac veins. It has no valves. The Internal Iliac Vein (66) is formed by the venae comi- tes of the branches of the internal iliac artery, the umbili- cal arteries excepted. It receives the blood from the ex- terior of the pelvis and from the organs in the cavity of the pelvis. The internal iliac vein lies at first on the inner side and then behind the internal iliac artery, and termi- ANATOMY AND PHYSIOLOGY. 1 65 nates opposite the sacro-iliac articulation, by uniting with, the external iliac to form the common iliac vein. This vessel has no valves. The Common Iliac Veins are formed by the uniop of the internal and external iliac veins in front of the sacro-ver- tebral articulation; passing obliquely upward to the right side of the vertebrae, they terminate upon the interverte- bral substance between the fourth and fifth lumbar verte- bra, where the veins of the two sides unite at an acute angle to form the inferior vena cava. The right common iliac ascends behind and to the outside of its correspond- ing artery. The left common iliac is at first on the inner side of the corresponding artery, and then behind the right common iliac artery. No valves are found in these veins. The Inferior Vena Cava (XVI., 36) returns to the heart the blood from all the parts below the Diaphragm. It passes upward along the front of the spine, on the right side of the aorta, and having reached the under surface of the liver, is contained in a groove in its posterior border. It then perforates the tendinous centre of the Diaphragm, enters the pericardium, where it is covered by its serous layer, and terminates in the lower and back part of the right auricle (XIL, 2). At its termination in the auricle it is provided with a valve, the Eustachian. This vein re- ceives in its course the following branches : Lumbar, Eight spermatic, Renal, Suprarenal, Phrenic, and Hepatic. l66 A COMPEND OF POETAL SYSTEM OF VEINS. (XVI.) The Portal Venous System is composed of foui large veins, which collect the venous blood from the viscera of digestion. These veins are the Inferior mesenteric (41), Superior mesenteric (40), Splenic (33), and Gastric. These collect the blood from the stomach, spleen, pancreas, and intestines. The trunk formed by their union (vena ptJrtge) enters the liver and ramifies throughout its substance; and its branches, again emerging from that organ as the hepa- tic veins (29), terminate in the inferior vena cava (26). These veins are destitute of valves. The Portal Vein (30) is formed by the Junction of the superior mesenteric, and splenic veins, in front of the vena cava, and behind the upper border of the great end of the pancreas. Passing upward through the right border of the lesser omentum to the under surface of the liver, it enters the transverse fissure, where it is somewhat enlarged, forming the sinus of the portal vein, and divides into two l)ranches, which accompany the ramifications of the hepa- tic artery and hepatic duct throughout the substance of the liver. The portal vein is about four inches in length, and, while contained in the lesser omentum, lies behind and between the hepatic duct and artery, the former being to the right and the latter to the left. Within the liver the portal vein receives the blood from the branches of the hepatic artery. The ramifications of the hepatic artery are distributed ANATOMY AND PHYSIOLOGY. 167 to the walls of the hepatic ducts and of the portal vein, to the capsule of Glisson, and to the peritoneal covering of the organ; while those of the portal vein pass into the glandular parenchyma, and, after traversing its substance as a capillary plexus, become continuous with the rootlets of the hepatic vein. Besides arterial blood, accordingly, which the liver receives in moderate quantity, it is supplied with venous blood in great abundance, received from the stomach, spleen, pancreas, and intestine. The complex organization of the liver, by reason of its peculiar relations to the digestive system, has made it ex- ceedingly difficult to arrive at definite conclusions concern- ing its functions. Whether its secretion, the bile, is wholly or partly excrementitious from the portal venous blood, or whether it has ingredients that are indispensable to the completion of the digestive processes, are questions yet unsettled among physiologists. The Renal Veins (XVI., 47, 50) are of large size, and placed in front of the renal arteries. The left is longer than the right, and passes in front of the aorta just below the origin of the superior mesenteric artery. It receives the left spermatic and the left inferior phrenic veins. It usually opens into the vena cava, a little higher than the right. THE KIDNEYS. (XVI., 37, 38.) The Kidneys are situated at the back part of the abdo- men, behind the peritoneum in the lumbar regions; each kidney extending from the eleventh rib nearly to the crest l68 ' A COMPEND OF of the ilium, but the right a little lower than the left, in consequence of the large space occupied by the liver. They are usually imbedded in a considerable quantity of fat,- which principally holds them in position, though they are also to some extent sustained by the large blood-vessels with which they are tonnected. Each kidney is about four inches in length, two in breadth, and one inch in thickness, the left being some- what larger, though thinner, than the right. In the intricate internal structure of the kidney by which its secretion is extracted from the blood, and which is in- dispensable to the health of the body, are the Malpighian (XCIV;, 2) bodies through which the function is per- formed. These are small rounded masses, exceedingly minute, of a deep red color, found only in the cortical structure of the kidney. Each of these little bodies are composed of two parts : a central glomerulus of vessels called a Malpighian tuft, and a membranous envelope, the Malpighian capsule; which latter is a small pouch-like commencement of a uriniferous tubule. The Suprarenal Cajj-suhs (XVI., 39) are two small flat- tened glandular bodies, of a yellowish color, situated at the back part of the abdomen, behind the peritoneum, and immediately in front of the upper part of either kidney; hence their name. These are ductless glands and their function is not known. THE CONSTITUENCY OF THE BLOOD. The 'Blood is a thick opaque fluid, varying in different parts of the body from a brilliant scarlet to a dark purple ANATOMY AND PHYSIOLOGY. 169 or nearly black color. It has a slightly alkaline reaction and a specific gravity of 1055. It consists, first, of a nearly' . colorless, transparent, alkaline fluid, the plasma, contain-' ing water, albuminous matters, and salts, in solution; and, secondly, of distinct corpuscles, or blood-globules, swim- ming in the liquid plasma. The globules form 40 per cent, the plasma about 60 per cent by volume of the entire mass. The specific gravity of the two is somewhat differ- ent. Their relative quantities, by weight, are more nearly equal than when estimated by volume, the exact propor- tions being as 45 to 55. The globules of the blood are of two kinds, red and vifhitc; of which the red are far more numerous, the pro- portion being about as 300 to 1. The red globules of the blood serve mainly as carriers of oxygen. The readiness with which they absorb this substance from the atmosphere, and their changes of color depending upon its supply or withdrawal, indicate that they have a special relation to its, introduction and distribution in the body. They are composed of an albuminous and a coloring matter, with mineral salts and water. The most important ingredient of the red globules is their coloring matter, or Jmmoglbbin. The physiological properties and functions of the vvrhite globules are not BO distinct as those of the red. Their great inferiority in number shows that they are less im- portant for the immediate continuance of the vital opera- tions; and the same thing may be inferred from their want of strongly-marked specific characters. For while the red globules of the blood vary in appearance to a marked de- gree in different classes, orders, and families, the white 170 A COMPEND OF globules present the same general features of size, form, and structure everywhere. The Plasma of the Blood is a transparent, colorless, homogeneous liquid, in which the blood-globules are sus- pended. It consists of water holding in solution mineral salts and albuminous matters with various crystallizable substances of organic origin. Its albuminous matters are the most abundant and important of its solid ingredients, It contains some thirteen ingredients, of which, in 1,000 parts, 903 are water, 53 are albumin, and 23 are paraglobu- lin. The albumin is doixbtless the nutritious element ^ar excellence. It in all probability supplies the greater part of the nitrogenous ingredients of the tissues, and provides for their daily nourishment and renovation. In this proc- ess it must suffer a variety of transformations, by which it is converted into the different albuminoid matters char- acteristic of muscular, nervous, glandular, and other struc- tures throughout the body. The ingredient next in abundance is 2Mraglobulin, the average quantity of which is about one-half of that of al- bumin. It is closely allied to albumin in its chemical relattons, and no doubt also in its physiological action; and it is possible that either one of these substances may be an intermediate stage of production or metamorphosis of the other. ' The fibrinogen of the plasma, being 0.3 of the mass, is the substance that produces the solid fibrin of coagulated blood. ANATOMY AND PHYSIOLOGY. Ifl THE CAPILLAEY CIECULATIOK The Capillary blood-vessels are minute inosculating tubes^ distributed through all the periphery, permeating the vas-- cular organs, and bringing the blood into close proximity with their tissues. They are continuous, on the one hand, with the terminal ramifications of the arteries, and, on the other, with the commencing rootlets of the veins. ^ As the arterial ramifications approach the capillary sys- tem, they diminish in size, and leave their external coat of connective tissue. Their middle coat is, at the same time, reduced to a single layer of fusiform muscular fibres, which become gradually less numerous, and at last disappear al- together. The vascular canal is thus finally composed only of a single tunic continuous with the internal coat of the arterial ramification. These minute ramifications of the vascular system are necessarily microscopic in their pro- portions. It is during its passage through the capillaries that the blood serves for the nourishment of the tissues, and for absorption, secretion, or elimination; The nutritious' in- gredients of the blood transude through their walls, and are appropriated by the tissues beyond. The conditions which influence the movement of the blood in the capillaries are somewhat different from those of the arterial and venous circulations. By the successive division of the arteries from the heart outward, the move- ment of pulsation is to a great extent equalized in their smaller branches. But in the neighborhood of the capil- 172 A COMPEND OF ' lary system they iSuddenly break up into a terminal rami- Hcation of still smaller vessels, and so lose, themselves at last in the capillary network. By this final increase of the vascular surface the equalization of the heart's action is completed. There is no longer any pulsating character in- the force which acts on the circulating fluid ; and the blood moves through the capillary vessels under a contin- uous and uniform pressure. This pressure is sufficient to propel the blood through the capillary plexus into the veins. The complete circuit of the blood through the vascular system, from the time it leaves the heart until it returns, when no special obstacle is interposed, is estimated at about twenty seconds. The condition of the blood in its passage through the secreting glands, such as the salivary glands and the kid- neys, is peculiar. Throughout the muscular system the blood leaves the muscles of a dark color, and this is the more intense when they are in active contraction; but the dark" color of the blood returning from these glands is inter- mittent. When the gland is in active secretion and its veins are discharging blood into -the general circulation, it is largely arterial in its character, but when the gland is in repose, the blood in the veins proceeding from it is dark, similar to that returned from the muscles. This would seem to indicate that while the blood is supplying the secretion to the gland it suspends its supply of oxygen to its tissues, and as the circulation is continuous it passes on, leaving the gland measurably unchanged in color. ANATOMY AND PHYSIOLOGY. 1/3 THE NERVOUS SYSTEM. This may be termed the great electro-magnetic system of the body, along whose lines pass signals of thought, sensation, and motion, under the control of the centre of government in the brain. It is the system through whfeh all the functions of the body are performed, and without which there could be neither mental nor physical action. Bones, miiscles, and viscera would all be inert without the powers it communicates through all the organism. The nervous system may be comprised under three gen- eral divisions : 1, a series of connected central organs called, collectively, the cerehro- spinal centre or axis; 2, of the ganglia; and, 3, of the nerves. The Cerebrospinal Centre consists of two parts, the spinal cord and the encephalon; the latter consists of the cere- brum, the cerebellum, the pons Varolii, and the medulla oblongata. (XXXIX., XL., XLI.) The Beain (encephalon) is contained in the cranial cavity. The cerebrum occupies a considerable part, of the cavity of the cranium, resting in the anterior and middle fossae of the base of the skull, and separated posteriorly from the cerebellum by the tentorium cerebelli. About the middle of its under surface is a narrow constricted portion, part of which, the crura cerebri, is continued onward into the pons Varolii below, and through it to the medulla oblon- gata and spinal cord; while another portion, the crura cerebelli, passes down into the cerebellum. 174 A compend of CEREBEUM— UPPER SURFACE. The Gerehmm constitutes the largest portion of the ea- cephalon. It is divided into two lateral halves or hemi- spheres, right and left, by the great longitudinal fissure,' which extends throughout the entire length of the cere- hrum in the middle line, 'reaching down to the base of the brain in front and behind, but interrupted in the middle by a broad transverse commissure of white matter, the cor- pus callosum (XL., A; XLI., 4), which connects the two hemispheres together. This fissure lodges the falx cerebri, and indicates the original development of the brain by two lateral halves. Each hemisphere presents an outer surface, which is convex, to correspond with the vault of the cranium; an inner surface, flattened, and in contact with the opposite hemisphere (the two inner surfaces forming the sides of the longitudinal fifisure) ; and an under surface or base, of more irregular form, which rests in front, on the anterior and middle fossse at the base of the skull, and behind- tipon the tentorium. Convolutions. The entire surface of each hemisphere presents a number of convoluted eminences, the convolu- tions, separated from each other by depressions (sulci) of various depths. The outer surface of each convolution, as well as the sides and bottom of the sulci, between them, are composed of gray matter, which is here called the cor- tical substance. The interior of each convolution is com- posed of white matter; and white fibres also blend with the gray matter at the sides and bottom of the sulci. By ANATOMY AND PHYSIOLOGY. I^S this arrangement the convolutions are adapted to increase the amount of gray matter without occupying much addi- tional space, while they also afford a greater extent of sur- face for the termination of white fibres in gray matter. There is no accurate resemblance between the convolu- tions in different brains, nor are they symmetrical on the two sides of the same brain. The sulci are generally an inch in depth; they also vary in different brains, and in different parts of the same brain; they are usually deepest on the outer convex surface of the hemispheres; the deepest is situated on the inner sur- face of the hemisphere, on a level with the corpus callosum, and corresponds to the projection in the posterior horn of the lateral ventricle, the hippocampus minor. The number and extent of the convolutions, as well as their depth, appear to bear a close relation to the intellec- tual power of the individual, as is shown in their increas- ing complexity of arrangement as we ascend from the low- est mammalia up to man. Thus they are absent in some of the lower order of mammalia, and they increase in num- ber and extent through the higher orders. In men they present the most complex arrangement. In the child at birth, before the intellectual faculties are exercised, the convolutions are simple, with few undulations; and the sulci between them are less deep than in the adult. In old age, when the mental faculties have diminished in activity, the convolutions become much less prominent. The. convolutions on the outer convex surface of the hemisphere are especially characteristic of the human brain, but are seldom symmetrical on the two 'sides. 176 A compeNd of Each hemisphere is divided into five lobes, the division being made by the main fissures and by imaginary lines drawn ta connect them. The fissure of Sylvius (XXXIX., 7; XL., B), between the anterior and middle lobes, and the fissure of Eolando (XXXIX., 8) are the principal fissures involved in these divisions. The chief convolutions which bound these several fis- sures are pretty constant, but the secondary convolutions, or those which form the bulk of the several lobes, vary greatly in their number and arrangement. The convolution of the corpus callosum (gyrus fornicatus) is always well marked. The supraorbital convolution on the under surface of the anterior lobe is well marked. The convolution of the longitudinal fissure bounds the margin of the fissure on the upper surface of the hemi- sphere. CEKEBEUM— UNDEE SUEFACE. (XL.) The under surface of each hemisphere presents three lobes, anterior, middle, and posterior. The various objects on the under surface of the cere- brum, in the order as they exist from before backward, are : Longitudinal fissure. Corpus callosum (A) and its pedun- cles. Lamina cinerea. Olfactory nerve (1). Fissure of Syl- vius (B). Anterior perforated space. Optic commissure (3). Tuber cinereum. Infundibulum. Pituitary body. Cor- pora albicantia. Posterior perforated space. Crura cerebri. ANATOMY AND PHYSIOLOGY. 1 77 The hemispheres are connected together by the corpus callosum, and the interval left between its under surface, the upper surface of the ganglia, and the parts closing the interpeduncular space, forms the general ventricular cav- ity. The upper part of this cavity is subdivided into two 'by a vertical septum, the septum lucidum, and thus the two lateral Ventricles are formed. The lower part of the cav- ity forrris the third ventricle, which communicates with the lateral ventricles above and with the fourth ventricle behind. The fifth ventricle is the interval left between the two layers composing the septum lucidum. The white matter of each hemisphere consists of three kinds of fibres: 1. Diverging or peduncular fibres, which connect the hemisphere with the cord and medulla ob- longata. 3. Transverse commissural fibres, which connect the two hemispheres. 3. Longitudinal commissural fibres, which connect distant parts of the same hemisphere. The cerebellum is situated in the inferior occipital fo'ssse, beneath the under surface of the posterior lobes of the cerebrum. It_ is connected to the rest of the encephalon by connecting bands, called crura; of these, two ascend to the cerebrum, two descend to the medulla oblongata, and two blend together in front, forming the pons Varolii. The ^o«s Varolii is that portion of the encephalon which rests upon the upper part of the basilar process and body of the sphenoid bone. It is the bond of union of the vari- ous segments above named, receiving, above, the crura from the cerebrum ; at the sides, the crura from the cere- bellum j and below, the medulla oblongata. The medulla oblongata (XLL, 9) is the upper enlarged 1/8 , A COMPEND OF portion of the spinal cord within the cranium, and extends from the lower border of the pons Varolii to the upper border of the atlas, beneath the cerebellum, .resting on the lower part of the basilar groove of the occipital bone. , The average weight of the brain in the adult male is 49| oz., that of the female 44 oz. The prevailing weight of the brain in the male ranges between 46 oz. and 53 oz. ; and in the female, between 41 oz. and 47 oz. In the male, the maximum weight out of 378 cases was 65 oz., and the minimum weight 34 oz. The maximum weight of the adult female brain, out of 191 cases, was 56 oz., and the mini- mum weight 31 oz. It appears that the weight of the brain increases rapidly up to the seventh year, more slowly to between sixteen and twenty, and still more slowly to between thirty and forty, when it reaches its maximum. Beyond this period, as age advances and the mental facul- ties decline, the brain diminishes slowly in weight, about an ounce for each subsequent decennial period. The size of the brain appears to bear a general relation to the intellectual capacity of the individual. DUEA MATEE. ■ 7%e Dura mater is a fibrous membrane lining the interior of the skull and spinal column. It is the periosteum of ihe inner surface, and is continuous with the pericranium, which envelops the outer surface, through the various foramina in the base. It has numerous arteries, chiefly distributed to the bodies ascending from the carotid arte-, ries and their branches. Its nerves are a branch of the ANATOMY AND PHYSIOLOGY. I79 fourth and filaments from the Gasserian ganglion, from the ophthalmic nerve, and from the sympathetic. It dips down between the two hemispheres, and covers the upper surface of the cerebellum, passing in between it and the occipital lobe. AEACHNOID MEMBEANE. The Arachnoid Membrane is extremely thin and is the serous membrane which envelopes the brain and spinal cord, and is then reflected on the inner surface of the dura mater. It is a shut sac consisting of a parietal and visceral layer. The parietal covers the inner surface of the dura mater, and passes with it between the hemispheres and between the occipital lobe and the cerebellum. PIA MATEE. The Pia Mater is a vascular membrane deriving its blood from the internal carotid and vertebral arteries. It con- sists of a minute plexus of blood-vessels, and invests the entire surface of the brain, dipping down between the con- volutions, and is prolonged into the interior, forming the ,velum interpositum and choroid plexuses of the fourth ventricle. It sends branches deep down into the substance of the brain. THE SPINAL COED. The Spinal cord (medulla spinalis) is the cylindrical elongated part of the cerebro-spinal axis which is contained in the vertebral canal. It extends from the upper border of the atlas to the lower border of the first lumbar verte- l80 A COMPEND OF bra, where it terminates in a slender filament of gray sub- stance, which is continued for some distance into the filum terminale._. In form, the spinal cord is a flattened cylinder. It presents, on its anterior surface, along the middle line, a longitudinal fissure, the anterior median fissure ; and, on its posterior surface, another fissure, which also extends along the entire length of the cord, the posterior median fissure. These fissures serve to divide the cord into two symmetrical halves, which are united in the middle line, throughout their entire length, by a transverse band of nervous substance, the commissure. If a transverse section of the spinal column be made, it will be seen to consist of white and gray nervous substance. The white matter is situated externally and forms the greater part. The gray substance occupies the centre; and is so arranged as to present on the surface of the section > two crescentic masses placed one in each lateral half of the cord, united together by a transverse band of gray matter, the gray commissure. Each crescent has an anterior and posterior horn. The posterior horn is long and yarrow, and approaches the surface of the postero-lateral fissure, near which it presents a slight enlargement. The anterior horn is short and thick, and , does not quite reach the sur- face, but extends toward the point of attachment of the anterior roots of the nerves. THE GANGLIA. 77ie Ganglia are nervous centres within the cranium and trunk, accessory to the cerebro-spinal axis, receiving and distributing nerves within the body. These will be ANATOMY AND PHYSIOLOGY. l8l considered as we proceed with the nerves with which they are connected. SPESTAL NEEVES. (XLII.) The Spinal Nerves are so called, because they proceed from the spinal cord and are transmitted through the in- tervertebral foramina, on either side of the spinal column. There are thirty-one pairs which are arranged into the following groups, corresponding to the region of the spine through which they pass : Cervical, 8 pairs ; Dorsal, 12 ; Lumbar, 5; Sacral, 5; and Coccygeal,!. Thus each group of nerves corresponds in number with the vertebrae in that jegion, except the cervical and coccygeal. Each spinal nerve arises by two roots, an anterior, or motor root, and a posterior, or sensory root (LIT.) The anterior roots arise from a linear series of foramina on the antero-lateral column of the spinal cord. The posterior roots are all attached to the posterior white columns only, but some of them pass through the gray substance into both the lateral and anterior white columns. A ganglion is developed upon the posterior root of each of the cervical nerves, with the occasional exception of the first cervical. Immediately beyond the ganglion the two roots coalesce, their fibres intermingle, and the trunk thus formed passes out of the intervertebral foramen, and divides into an anterior branch for the supply of the anterior part of the body, and a posterior branch for the posterior part, each branch containing fibres from both roots. J.S2 A COMPEND OF The anterior branches are conne'cted by slender filaments from the sympathetic. In the dorsal region the anterior ^branches are completely separated from each other, and are uniform in their distribution; but in the cervical, lumbar, and sacral regions, they form intricate plexuses previous to their distribution. The posterior branches pass backward, and, dividing into external and internal branches, are distributed to the mus- cles and integument behind the spine. The first cervical and the lower sacral nerves vary somewhat from this gen- eral description. " Cervical Nerves. — The first four cervical nerves issue from the spinal column above the fifth vertebra, and their ante- rior branches form the cervical plexus (XLVIL, 30). The anterior branches of the f ourlower cervical nerves, together with the first dorsal nerve, form the brachial plexus (XLVII., 21). The Cervical Plexus is situated opposite the four up- per vertebrae, resting upon the Levator anguli scapulae, and scalenus medius muscles, and covered in by the sterno- mastoid (I., 13, 14, 15). Its branches and their distribu- tion are as follows : Superficialis Colli arises from the second and third cer- vical nerves, diyides beneath the platysma (I., 18) into two branches, which are distributed to the anterior and lateral parts of the neck. Auricularis Magnus arises from the second and third cervical nerves, ascends upon the sterno-mastoid muscle beneath the platysma to the parotid gland, where it di- vides into numerous branches. These are distributed to ANATOMV AND PHYSIOLOGY. 183 the muscles of the face, to the parotid gland (XXI., 1), and to the integument behind the ear. Occipitalis Mitwr arises from the second cervical nerve, and is distributed to the back part of the side of the head, supplying the integument and occipito-frontalis muscle (I., 4). A branch from this nerve supplies the Attolens aurem (I., 3), and the integument of the upper and back part of the auricle. The sternal, clavicular, and acromial branches arise from the third and fourth cervical nerves. The sternal branch crosses obliquely over the sterno-mas- toid, and supplies the integument as far as the median line. The clavicular branch crosses the clavicle and supplies the integument over the pectoral (II., 30) and deltoid mus- cles (II., 31), communicating with the cutaneous branches of the upper intercostal nerves. The acromial branch crosses obliquely across the outer surface of the Trapezius (I., 16, 17) and the acromion, and supplies the integument of the upper and back part of the shoulder. Communicating branches pass from the loop between the first and second cervical nerves in front of the atlas to the pneumogastric, hypoglossal, sympathetic, and fifth cervical. Muscular brandies proceed from the loop formed be- tween it and the second, to supply the Anterior recti and Eectus lateralis muscles. The Communicans noni is derived from the .second and third cervical, descends and forms a loop with the descendens noni, and is distributed in the- omohyoid muscle. Tlie Phrenic Nerve arises from the third and fourth cer- l84 V A COMPEND OF vical nerves and receives a branch. from the fifth. It passes down and enters the chest, and descends vertically to the Diaphragm (XVI., 37), where it divides into branches which are distributed to the under side of that organ. The two phrenic nerves differ somewhat in their relations in the thorax by reason of the difference of the two sides, occasioned by the inclination of the heart to the left side. The right nerve passes, down on the outer side of the su- perior vena cava (XII., 16), and the left nerve passes down in front of the arch of the aorta (XII., 6). These nerves have connection with the sympathetic (L., 1), the fifth and sixth cervical, the solar plexus, the hepatic plexus, the suprarenal capsule (XVI., 39), and inferior vena cava (XVI., 36). Gommunicating branches of the cervical plexus commu- nicate with the spinal accessory nerve, in the sterno-mastoid muscle, in the occipital triangle, and beneath the Trapeziu's. Muscular branches are distributed to the Sterno-mastoid, ' Levator anguli scapulas. Scalenus medius, and Trapezius (I., 13, 14, 15, 16, 17). The posterior branches of the cervical nerves, with the exception of those of the first two, pass backward, and di- vide behind the posterior Intertransverse muscles into ex-, ternal and internal branches. The external branches supply the muscles at the side of the neck. The internal branches of the third, fourth, and fifth ■nerves pass between the Semi-spinalis and Complexus mus- cles, and having reached the spinous processes, perforate the aponeurosis of the Splenius and Trapezius, and are ANATOMY AND PHYSIOLOGY. 1 85 continued ontward to thg integuments over the Trapezius; those from the three lower cervical nerves are placed beneath the Semi -spinalis, which they supply. These internal branches supply the Complexus, Semi-spinalis colli, Inter- spinales, and Multifidus spinas. The posterior branch of the first cervical nerve escapes from the spinal canal between the occipital bone and the atlas, behind the vertebral artery, and supplies the Kecti and Oblique muscles and the Complexus. The posterior branch of the second cervical nerve is the largest of all the posterior cervical nerves. It emerges from the spinal canal between the posterior arch of the atlas and lamina of the axis, below the Inferior oblique muscle, which it supplies, and receives a filament from the first cervical. It then divides into an external and internal branch, called the occipitalis major, is joined by a filament from the third cervical nerve, and ascending on the back part of the head, divides into two branches, which supply the in- tegument of the scalp communicating with the occipitalis minor. It gives off an auricular branch to the back part of the ear and muscular branches to the Complexus. The joosfonor branch of the third cervical differs from those of the other cervical nerves in its supplying an addi- tional filament to the integument of the occiput, and which supplies the skin on the lower back part of the head. The Brachial Plexus (XX., 75, 76) is formed by the anterior branches of the four lower cervical and first dor- sal nerves. It extends from the lower part of the side of the neck to the Axilla. It is very broad and presents little of a plexiform arrangement at its commencement, is nar- I 86 A COMPEND OF &." row opposite the clavicle, becomes broad, and forms a more dense interlacement in the axilla, and divides opposite the coracoid process into numerous branches for the supply of the upper limb. The fifth and sixth nerves unite near their exit from the spine into a common trunk; the sev^th . nerve joins this, trunk near tlie outer border of the middle scalenus ; and the three nerves thus form one large single cord. The eighth cervical and first dorsal nerves unite behind the Anterior scalenus into a common trunk! Thus two large trunks are formed, the upper one by the union of the fifth, sixth, and seventh cervical, and the lower one by the eighth cervical and the first dorsal.. These two trunks accompany the subclavian artery to the axilla, lying upon its outer side, the trunk formed by the union of the last, cervical and first dorsal being nearest to the vessel. Opposite to the clavicle, and sometimes in the axilla, each of these cords gives ofE a fasciculus, by the union of which a third trunk is formed, so that in the middle of the axilla three cords are found, one lying on the outer side of the axillary artery,- one on its inner side, and one -behind. The brachial plexus communicates with the cervical plexus by a branch from the fourth to the fifth nerve, and with the phrenic nerve by a branch from the fifth cervical, which joins that nerve on the Anterior scalenus muscle; the cervical and first dorsal nerves are also joined by filaments from the middle and inferior cer- vical ganglia of the sympathetic close to their exit from the intervertebral foramina. In the neck, the brachial plexus lies at first between the Anterior and Middle scaleni. muscles, and then above and to the outer side of the sub- ANATOMY AND PHYSIOLOGY. 1 8/ clavian artery; it then passes behind the clavicle and Sub- clavius muscle, lying upon the first serration of the Serra- tus magnus (II., 33), and the Subscapularis muscles. In the axilla it is placed on the outer side of the first portion of the axillary artery; it surrounds the artery in the second part of its course, one cord lying upon the outer side of that vessel, one on the inner side, and one behind it ; and at the lower part of the axillary space gives off its terminal branches to the upper extremity. The branches of the brachial plexus above the clavicle are communicating branch, muscular branches, posterior thoracic, and Suprascapular. The communicating branch with the phrenic is derived from the fifth cervical nerve; it joins the phrenic on the Anterior scalenus muscle. The muscular branches supply the Longus colli, Scaleni, Khomboidii, and Subclavius muscles. The posterior thoracic supplies the Serratus magnus, and is remarkable for the length of its course. It arises by two roots from the fifth and sixth cervical nerves imme- diately after their exit from the spinal column. It extends along the side of the chest to th^ lower border of the Serratus magnus (II., 33) and supplies it with numerous filaments. The suprascapular arises from the cord formed by the fifth and seventh cervical nerves, passes outward beneath the Trapezius, enters the supraspinous fossa through the notch in the upper border of the scapula, and, passing be- neath the supraspinatus muscle, curves in front of the spine of the scapula to the infraspinous fossa. In the Su- 1 88 , A COMPEND OF pra^pinous fossa it gives off two branches to the Supraspi- natus muscle, ijnd an articular filament to the shoulder- joint,, and in the inf raspinous fossa it gives off two branches to the infraspinatus muscle, besides some filaments to the shoulder-joint and scapula. The branches of the brachial plexus below the clavicle (XX) are Anterior thoracic. Subscapular, Circumflex, Musculo-cutaneous (78), Internal cutaneous. Lesser in- ternal cutaneous, Median, Ulnar (77), and Musculo-spiral (XLVII., 23, 23, 24, 26). The Anterior Thoracic Nerves supply the Pectoral mus- cles (II., 20). The Subscapular Nerves supply the Subscapularis, Teres major, and Latissimus dorsi muscles. The Circumflex Nerve supplies some of the muscles and the integument of the shoulder, and the shoulder-joint. The Musculo- Cutaneous Nerve supplies some of the muscles of the arm and the integument of the forearm. The Internal Cutaneous Nerve arises from the inner cord in common with the ulnar and internal head of the median, and passing down the inn'er side of the arm, pierces the deep fascia with the basilic vein, about the middle of the limb, and, becoming cutaneous, divides into branches. One filament supplies the integument covering the Biceps (III., 28) muscle, nearly as far as the elbow. The anterior branch descends on the anterior surface of the ulnar side of the forearm, distributing filaments to the integuments as far as the wrist. The posterior branch passes obliquely downward on the inner side of the basilic vein, winds over the internal condyle of the humerus to the baqk pf the ANATOMY AlSfD PHYSIOlOGV. 189 forearm, and descends on the posterior surface of its ulnar side to a little below the middle, distributing filaments to the integument. The Lesser Internal Cutaneous Nerve is distributed to the integuments on the inner side of the arm. The Median Nerve (XL VII., 23) passes from its origin in the brachial plexus down the middle of the arm arid forearm to the hand, passing beneath the annular liga- ment. No branches are given off in the arm, but in the forearm its muscular branches supply all the superficial muscles except the Flexor carpi ulnaris; its anterior inter- osseous supplies the deep muscles on the front of the fore- arm, except the Plexor carpi ulnaris and part of the Flexor profundus digitorum. The palmar cutaneous branch arises near the wrist, and after passing the annular liga- ment supplies the skin over the ball of the thumb and the integument of the palm of the hand, anastomosing with the cutaneous branch of the ulnar. In the palm of the hand the median nerve divides into two "branches, which in turn are subdivided and distributed to the thumb and fingers. These are called digital branches. The Ulnar Nerve (XLVII., 23) is placed along the inner side of the arm and is distributed to the forearm and hand. It arises from the inner, cord of the brachial plexus, and at the wrist crosses the annular ligament and divides into two branches. It distributes articular branches to the elbow- joint; Muscular branches, near the elbow, to the Flexor carpi ulnaris and Flexor profundus digitorum; cutaneous branches to the integument of the forearm ; a dorsal cuta- igo A compend of neons branch to the little and ring fingers ; articular fila- ments to the wrist; a superficial palmar branch to the in- tegument of the inner side of the hand, and terminates in digital branches to the fingers and a deep palmar branch to the muscles of the palm and fingers. The Musculo-Spiral Nerve, the largest branch of the brachial plexus, supplies the muscles of the back part of the arm and forearm and the integument of the same parts, as well as that of the hand. It arises from the posterior cord of the brachial plexus. It winds round the humerus in the spiral groove with the superior profunda artery, passing from the inner to the outer side of the bone. Its muscular branches are internal, posterior, and external; they supply the triceps. Anconeus, Supinator longus, Ex- tensor carpi radialis longior, and Brachialis anticus. These branches are derived frolJj^ the nerve at the posterior side of the arm. Its cutaneous branches are three in number, one internal and two external. The internal branch sup- plies the integument on the inner side of the arm as far as the olecranon. The two external cutaneous branches per- forate the outer head of the Triceps at its attachment to the humerus. The upper and smaller one follows the course of the cephalic vein to the front of the elbow, sup- plying the integument of the lower half of the upper arm on its anterior aspect. The lower branch pierces the deep fascia below the insertion of the Deltoid, and passes down the outer side of the arm and elbow, and along the back part of the radial side of the forearm to the wrist, supply- ing the integument in its cobrse, and joining, near its ter- mination, with a branch of the external cutaneous nerve. ANATOMY AND PHYSIOLOGY. I9I The radial branch of the musculo-spiral nerve passes along the front of the radial side of the forearm to the commencement of its lower third, where it divides into two branches, external and intei:nal. The external branch supplies the integument of the radial side and ball of the thumb, joining with the posterior branch of the external cutaneous nerve. The internal branch communicates, above the wrist, with a branch from the external cutaneous, and on the back of the hand forms an arch with the dor- sal branch of the ulnar nerve. It then divides into four ' digital nerves which are distributed to the thumb and fin- gers. The posterior interosseous branch of the Musculo- spiral winds to the back of the forearm, and descending to the back of the carpus, presents a gangliform enlarge- ment from which filaments are distributed to the ligaments and articulations of the carpus. It supplies all the muscles of the radial and posterior brachial regions, excepting the Anconeus, Supinator longus, and Extensor carpi radialis longior. This nerve being on the back of the arm is not shown on the manikin. DORSAL NERVES. The Dorsal Nerves are twelve in number on each side. The first appears between the first and second dorsal ver- tebrae and the last between the last dorsal and first lumbar. The roots increase in length from above downward, and remain, in connection with the spinal cord, within the canal for a distance equal to the height of two vertebrae, and at their exit each divides into two branches, a posterior (dor- sal) and an anterior (intercostal) branch. 192 A COMPEND OF The posterior branches of the dorsal nerves pass backward between the transverse processes, and divide into external branches. The external branches supply the Longissimus dorsi and Sacro-lumbalis and the Levatores costarum. The internal branches of the six upper nerves pass in- ward and supply the Multifidus spinse and Semi-spinalis dorsi muscles, and then becom§ cutaneous beside the spi- nous processes. The internal branches of the six lower nerves are distributed to the Multifidus spinse 'without giving off any cutaneous filaments. The cutaneous branches of the dorsal nerves are twelve in number, the six upper being derived from the internal branches and the six lower from the external branches. INTEKCOSTAL NERVES. (XLII.) The Intercostal Nerves (anterior branches of the dorsal nerves) are twelve in number on each side. They are dis- tributed to the parietes of the thorax and abdomen sepa- rately from each other. Each nerve is connected with the adjoining ganglion (a, a) of the sympathetic by one or two filaments. The six upper nerves, with the exception of the first, are distributed to the chest. The six lower sup- ply the chest and abdomen. The upper intercostal nerves pass forward in the inter- costal spaces with the intercostal blood-vessels. Near the Sternum they cross the internal mammary artery and sup- ANATOMY AND PHYSIOLOGY. I93 ply the integument of the mamma and front of the chest, forming the anterior cutaneous nerves of the thorax. There are numerous anterior and posterior lateral cutane- ous branches arising midway between the vertebrse and the sternum (XXXVIII., 31, 32, 33). The lower intercostal nerves (excepting the last) are ar- ranged as the uppfer ones as far as the anterior extremities of the intercostal spaces, where they pass behind the costal cartilages. They supply the Eectus muscle and terminate in branches, which become subcutaneous, near the linea alba. These branches supply the integument in front. The lower intercostal nerves supply the intercostal and ab- dominal muscles, and about the middle of their course, give off lateral cutaneous branches which are distributed to the integument of the abdomen. LUMBAR NERVES. The Lumbar Nerves (XLII., 29) are five in number on each'side; the first appears between the first and second lumbar vertebrae, and the last between the last lumbar and the base of the sacrum (XLII., c; XLIII., k). The roots of the lumbar nerves are the largest and their filaments the most numerous of all the spinal nerves, and they are closely aggregated together at the lower end of the cord. The roots of these nerves have a vertical direc- tion, and are of considerable length, especially the lower ones, since the spinal cord descends only to the first lum- bar vertebra. As they issue from the spinal column they divide into anterior and posterior branches. 13 194 .^ A COMPENb OF The posterior brandies pass backward «and divide into external and internal branches. The External branches supply the Erector spinas aiid intertransverse muscles. Cutaneous branches descend over the .crest of the back part of the ilium, to be distrib- uted to the integument of the gluteal region, some of the filaments passing as far as the trochanter major. The Internal branches pass inward close to the articular processes of the vortebrse, and supply the Multifidus spinse and interspinalis muscles. The anterior branches of the lumbar nerves increase in size from above downward. At their origin they communicate with the lumbar ganglia of . the sympathetic by long, slender filaments, which accom- pany the lumbar arteries round the sides of the bodies of the vertebrsB, beneath the Psoas muscle. The anterior branches of the four upper nerves are connected together in this situation by anastomotic loops, and form the lum- bar plexus. The anterior branch of the fifth lumbar, joined with a branch from the fourth, descends across the base of the sacrum to join the anteripr branch of the first sacral nerve, and assist in the formation of the sacral plexus. The cord resulting from the union of these two nerves is called the lumbo-sacral nerve (XLII., 30, 31). LUMBAE PLEXUS, The Lumbar Plexus (XLII., 30) is formed by the loops of communication between the anterior branches of the four upper lumbar nerves. The plexus is narrow above, and occasionally connected with the last dorsal by a slen- ANATOMY AND PHYSIOLOGY.- I9S der branch, the dorsi-lnmbar nerve; it is broad below, where it is joined to the sacral plexus by the lumbosacral . cord. It is situated in the substance of the Psoas muscle near its posterior part, in front of the transverse processes of the lumbar vertebrs. , The mode in which the plexus is formed is the follow- ing: The first lumbar nerve gives dfl the ilio-hypogastric and ilio-inguinal nerves and a communicating branch to • the second lumbar nerve. The second gives off the exter- nal cutaneous and genito-crural and a communicating branch to the third nerve. The third nerve gives a de- scending filament to the fourth, and divides into two branches which assist in forming the anterior cruml and obturator nerves; sometimes also it furnishes a part of the accessory obturator. The fourth nerve completes the for- mation of the anterior crural and the obturator and gives off a communicating branch to the fifth lumbar; some- times it also furnishes part of the accessory obturator. The branches of the lumbar plexus are the Ilio-hypogas- tric, Ilio-inguinal, Genito-crural, External cutaneous. Ob- turator, Accessory obturator, arid Anterior crural nerves. The first two and part of the third suj^ply the lower part of the parietes of the abdomen; all the remaining nerves supply the fore part of the thigh and the inner side of the leg (XLIL, e, 32, 33, 34, 35). The Ilio-hypogastric JS'erve, issuing from the first lum- bar nerve, divides into two branches, the iliac and hypo- gastric. The iliac branch is distributed to the integument of the gluteal region. The hypogastric branch is distrib- uted to the integument covering the hypogastric region. 196 A COMPEND OF The Ilio-inguinal Nerve arises also from the first lum- bar nerve, and is distributed to the viscera in the lower portion of the pelvis. The Genito-crural Nerve arises from the second lumbar, and by a few fibres from the cord of communication be- tween it and the first. It divides into a genital and crural branch. The genital branch descends on the external iliac artery, sending a few filaments around that vessel; it then pierces the fascia transversalis, and passing through the abdomi- nal ring, descends to the viscera below. The crural branch passes along the inner margin of the Psoas muscle, beneath Poupart's ligament, into the thigh, where it pierces the fascia lata, and is distributed to the integument of the upper anterior aspect of the thigh, communicating with the middle cutaneous nerve. A f«w filaments pass on to the femoral artery (XLII., ' 33). The External Cutaneous Nerve arises from the second ^ 'J lumbar, or from the loop between it and the third. It passes beneath Poupart's ligament into the thigh and di- vides into two branches. The anterior branch subdivides into branches which are distributed to the integument along the outer anterior part of the thigh as far down as the knee. This nerve occasion- ally communicates with the long saphenous nerve. 'Yhe pos- terior branch subdivides into branches distributed to the outer posterior surface of the thigh, supplying the integu- ment as far as the middle of the thigh. The Obturator Nerve (XLII., 35) arises by two branches : ANATOMY AND PHYSIOLOGY. I97 one from the third and the other from the fourth lumbar nerve. It descends to the upper part of the obturator fo- ramen (XLIIL, m), where it enters the thigh and divides into anterior and posterior branches, separated by the Ad- ductor brevis muscle. These branches are distributed to the Obturator externus and Adductor muscles of the thigh (V., 46, 48), the articulations of the hip and knee, and occasion- ally the integument of the thigh and leg. Some filaments are distributed to the femoral and popliteal arteries (XIX., 1, 3). The Accessory Obturator Nerve is of small size and some- times does not exist at all; its function, as its name indi- cates, being to aid in the work of the obturator. When it is absent, additional branches from the obturator perform its functions. The Anterior Crural Nerve (XLII., 33) is the largest branch of the lumbar plexus. It supplies muscular branches to the Iliacus, Pectineus, and all the muscles on the front of the thigh, excepting the Tensor vaginae femoris; cuta- neous filaments to the front and inner side of the thigh and to the leg and foot; and articular branches to the knee. It arises from the third and fourth lumbar nerves, receiv- ing a fasciculus from the second. It descends through the fibres of the Psoas muscle and issues from the pelvis be- neath Poupart's ligament (II., 26), into the thigh, and di- vides into an anterior or cutaneous and posterior or mus- cular part. Withm the pelvis the anterior crural gives off from its outer side some small branches to the Iliacus and a branch to the femoral artery, which is distributed upon the upper 198 A COMPEND OF part of that vessel. Sometimes this branch arises lower down in the thigh. External to the pelvis the following branches are given off : From the anterior division, Middle cutaneous, Internal cutaneous, and Long saphenous; from the posterior divi- sion, Muscular and Articular. The anterior division by its divisions and subdivisions is distributed to the' front of the leg and foot., The two br^jiches of the posterior divi- sion supply the Pectineus and all the muscles in the front ,■ of the thigh except the Tensor vagina femoris and Sarto- rius and the capsular ligament and synovial membrane of the knee-joint. SAOKAL AND COCCYGEAL NBEVES. The sacral nerves are five in number on each side. The four upper ones pass from the sacral canal through the sacral foramina; the fifth through the foramen between the sacrum and coccyx. The roots of origin of the upper sacral (and lumbar) nerves are the largest of all the spinal nerves; while those of, the lowest sacral and coccygeal nerves are the smallest. These roots are longer than other spinal nerves by rea- son of the termination of the spinal *cord within the first lumbar vertebrae. The roots of origin of these nerves are called collectively cauda equina. Each of these nerves, as with other spinal nerves, divides into anterior and pos- terior branches. The posterior branches of the thr^e upper ones are divided into internal and external. The external branches communicate with one another, and with the last ANATOMY AND PHYSIOLOGY. I99 1 lumbar and fourth sacral nerves, by means of anastomizing loops. These branches pass 6utward to the outer surface of the great sacro-sciatfc ligament, where they form a sec- ond series of loops beneath the Gluteus maximus muscle. Cutaneous branches frOm this second series of loops pierce the muscle and supply the integument over the posterior part of the gluteal region (XXXVI., 1). The tivo lower posterior sacral nerves join with each other and with the coccygeal nerve so as to form loops on the back of the sa- crum, filaments from which supply the integument oyer the coccyx. The first, second, and third sacral nerves, with the lumbo-sacral, unite to form the sacral plexus (XLII., 31.) All the anterior sacral nerves connect with the sacral ganglia of the sympathetic (a). The fourtli anterior sacral nerve sends a branch to the sacral plexus. The remaining portion of the nerve divides into visceral and muscular branches; and a communicating filament descends to join the fifth sacral nerve. The visceral branches are distributed to the viscera of the pelvis communicating with the sympathetic nerve, thus entering into the structure of the hypogastric plexus (LI., 10). The muscular branches are distributed to the Levator ani, Goccygeus, and Sphincter ani. Cutaneous filaments are also distributed to this portion of the pelvis. The fifth anterior sacral nerve passes from the lower end of the sacral canal, pierces the Coccygeus muscle, and descends upon its anterior surface to the tip of the coccyx, where it perforates that muscle, to be distributed to the integument over the back part and sides of the coccyx. 200 A COMPEND OF This nerve communicates above with the fourth sacral and below with the coccygeal nerve p,nd supplies the Coccygeus muscle. ' The anterior branch of the coccygeal nerve is a delicate filament which escapes at the termination of the sacral canal. It pierces the sacro-sciatic ligament and Coccygeus ■ muscle, is joined by a branch from the fifth anterior sacral, and becomes lost in the integument at the back part and sides of the coccyx. SACEAL PLEXUS. The Sacral Plexus (XLII., 31) is formed by the lumbo- sacral, the anterior branches of the three upper sacral nerves, and part of the fourth. These nerves proceed in different directions; the upper ones obliquely downward , and outward, the lower one nearly horizontally, and they all unite into a single broad flat cord. The sacral plexus is triangular in form, its base corresponding with the 'exit of the nerves from the sacrum, its apex, with the lower part of the great sacro-sciatic foramen (XLIIL, 1). It rests upon the anterior surface of the Pyriforjnis, and is covered in front by the pelvic fascia, which separates it from the sciatic and pudic branches of the internal iliac ■ artery and from the viscera of the pelvis. The branches of the sacral plexus are Muscular, Supe- rior gluteal, Pudic, Small sciatic, and Great sciatic (XLII., 34). 'Yhe muscular branches supply the Pyriformis, Obturator jnternus, the two Gemelli, and the Quadratus femoris. ANATOMY AND PHYSIOLOGY. 201 The Superior Gluteal Nerve arises from the back part of the lumbo-sacral, and passing out of the pelvis through the sacro-sciatic foramen accompanied by the gluteal vessels, divides into superior and inferior branches. The superior branch supplies the Gluteus minimus and Gluteus medius muscles (XXXVL, 1). The inferior branch crosses obliquely between the two above-mentioned muscles, "distributing filaments to both, and terminates in the Tensor vaginas femoris, extending nearly to its lower end. The Pudic Nerve arises from the lower part of the sacral plexus, and leaves the pelvis through the sacro- sciatic foramen. It then crosses the spine of the ischium and re-enters the pelvis through the lesser sacro-sciatic foramen. It accompanies the pudic vessels upward and forward along the outer wall of the ischio-rectal fossa, be- ing covered by the obturator fascia, and divides into two terminal branches; other numerous branches of the pudic nerve are distributed to the viscera of the pelvis and thighs. The Small Sciatic nerve supplies the integument of the perineum and back part of the thigh and leg, and one muscle, the Gluteus maximus. It is usually formed by the union of two branches which arise from the lower part of the sacral plexus. It descends beneath the Gluteus maxi- mus (XXXVI., 1) with the sciatic artery, and at the lower border of that muscle passes along the bacls, part of the^ thigh, beneath the fascia lata, to the lower part of the popliteal region, below the knee-joint where it pierces the fascia and becomes cutaneous. It then accompanies the external saphenous vein below the middle of the leg, 202 A COMPEND OF its terminal filaments communicating with the external saphenous nerve. The Great Sciatic Nerve (LVIII., 1) supplies nearly the whole of the integument of the leg, the muscles of the back of the thigh, and. those of the leg and foot. It is the largest nervous cord in the body, measuring three-quarters of an inch in breadth, and is the continuation of the lower part of the sacral plexus (XLIL, 31). It passes out of the pelvis through the great sacro-sciatic foramen (XLIII., 1) below the Pyriformis muscle. It descends between the trochanter major and tuberosity of the ischium along the back part of the thigh, to about its lower third, where it divides into two large branches, the internal and external popliteal nerves (XLIX., 36). The' branches of the nerve before its divisiion are articu- lar and muscular. The articular branches supply the hip-joint, perforating its fibrous capsule posteriorly. The muscular tranches are distributed to the Biceps, Semi-tendinosus, and the Semi-membranosus, and a branch to the Adductor magnus. The Internal Popliteal Nerve (LVIII., 2), the larger of the two terminal branches, of the great sciatic, descends along the back part of the thigh, through the middle of the popliteal space, to the lower part of the popliteus mus- cle, where it passes with the artery beneath the arch of the Soleus, and becomes the posterior tibial. It lies at first very superficial, and at the outer side of the popliteal ves- sels; opposite the knee-joint it is in close relation with the vessels, and crosses the artery to its inner side. ANATOMY AND PHYSIOLOGY. 203 The branches of this nerve are articular, muscular, and a cutaneous branch, the short saphenous nerve. The articular branches supply the knee-joint. The mjiscular branches, four or five in number, arise from the nerve as it lies between the two heads of the Gastrocnemius muscle. They supply that muscle, the Plantaris, Soleus, and Popliteus. The short saphenous nerve descends between the two heads of the Gastrocnemius muscle, and about the middle of the back of the leg pierces the deep fascia, and receiv- ing a communicating branch from the external popliteal nerve. The nerve then continues its course down the leg near the outer margin of the tendo Achillis, in company with the external saphenous vein, winds round the outer malleolus, and is distributed to the integument along the outer side of the foot and little toe, communicating on the dorsum of the foot with the musculo-cutaneous nerve. The Posterior Tibial nerve, the extension of the internal popliteal, passes along the back part of the leg with the posterior tibial vessels to the interval between the inner malleolus and the heel, where it divides into the external and internal plantar nerves. In the lower part of the leg it is placed parallel with the inner margin of the ^ tendo Achillis. The branches of the posterior tibial nerve are muscular and plantar-cutaneous. The muscular branches supply the Tibialis posticus. Flexor longus digitorum, and Flexor longus pollicis mus- cles; the branch to the latter muscle accompanying the peroneal artery. 204 A COMPEND OF The plantar-cutaneous branch perforates the internal anaular ligament and supplies the integument of the heel and inner side of the sole of the foot. The internal plantar nerve, the larger of the two terminal hranches of the posterior tibial, accompanies the internal plantar artery along the inner side of the foot. It passes forward between the Abductor poUicis and Flexor brevis digitorum, divides opposite the bases of the metatarsal bones into four digital branches, and communicates with the external plantar nerve. The external plantar nerve completes the nervous supply- to the structures of the fOot. The External Popliteal or Peroneal Nerve (XLIX., 36), about half the size of the internal popliteal, descends ob- liquely along the outer side of the popliteal space to the fibula (XLV., v) close to the margin of the Biceps muscle. About an inch below the head of the fibula it pierces- the origin of the Peroneus longus, and divides beneath that muscle into the anteiior tibial and musculo-cutaneous nerves. The branches of the peroneal nerve, previous to its divi- sion, are articular and cutaneous. The articular branches are distributed to the knee-joint. The cutaneous branches supply the integument along the back part and outer side of the leg, as far as its middle or lower part; a branch sometimes continues down to the heel. « The Anterior Tibial Nerve (XLIX., 38) commences at the bifurcation of the peroneal nerve, between the fibula ANATOMY AND PHYSIOLOGY. 205 fore part of the interosseous membrane, and reaches the outer side of the anterior tibial artery above the middle of the leg ; it then descends with the artery to the front of the ankle-joint, where it divides into an external and internal branch. This nerve lies first on the outer side of the anterior tibial artery, then in front of it, and again at its outer side at the ankle-joint. The branches of the anterior tibial are the muscular nerves to the Tibialis anticus. Extensor longus digitorum, Peroneus tertius, and Extensor proprius pollicis muscles. The external or tarsal branch of the anterior'tibial passes outward across the tarsus, and having become ganglionic, supplies the Extensor brevis digitorum and the articular tions of the tarsus and metatarsus. The internal branch, the continuation of the nerve, accompanies the dorsalis pedis artery along the inner side of the dorsum of the foot, and at the first interosseous space divides into two branches, which supply the adjacent sides of the great and second toes, communicating with the in- ternal division of the musculo-cutaneous nerve. The Musculo-cutaneous Nerve (XLIX., 39) supplies the muscles on the fibular side of the leg and the integument of the dorsum of the foot. It passes forward between the peronei muscles and the Extensor longus digitorum, pierces thd deep fascia at the lower third of the leg on its front and outer side, and divides into two branches. This nerje, in its course between the muscles, gives off muscu- lar branches to the Peroneus longus and brevis, and cuta- neous filaments to the integument of the lower part of the leg. The internal branch passes in front of the ankle- 2o6 A-COMPiENJ) OF joini and 'Hilong the dorsum of the foot, supplying ' the inner side of the greatj^toe and the adjoining sides of, the second and 'thirds toes. \,' It also supplies the integument of the injier ankle an(|'jniier side of the foot, communicating Tvitlj tfe'e internal sajft,es6otis.nerve, and join^j-with the anterior tibial nerve bmween the great and second toes.; Th'6 eifforwafJrawc/i, the larger, passes" along the outer.side of the dorsum of the foot, to be'distrihuted to the. adjoin- ing sides of the third, fourth, and :^th toes. It also -sup- plies the integument of the outer anlJle and oute^side of the fod*, communicating with the short saphenous nerve (XLiX.). THE SYMPATHETfC IfEEVE. (LL) The Sympathetic 'ingrvB 'is so called :from the opinion entertain.ed that through it is produced a ^rn.patA%hetTTe^ the affections of distaAjorgans., It consists of Series of ganglia, coiiheeted toa^ffi^r fey intejrvening^fl^rds (a)- 'ex- tendingpn'eAch.side of tW vertebral eolumrna-om ^e base' 06 the skull "to -the coccyx *(XLII., a)l It may, moreover, be traced up into the head, where the ' ganglia, which are all in connection with the^; fifth, cranial 'iierve (XLL, 14), occupy spaces between the cranial tod facial bdfllBs. Thes^ two gangliated cords lie parallel with one another as far as-the saijtum, on which bone they convergte, communiqat-H , ing togetlier through a sipgle ganglion (ganglion impar) placed in front of-^he cop'^x (L., 9).' Some anatomists' alsQ/itMe thaf^he twffoordl |,re joined at their cepjialic r> . Anatomy anI) physiology. - • ■ 'io'j '>■■ ■ - . v-^ ' • ■ extremity thrortgha small ganglioti-(tlieganglfcn of Ribes) ■ situated upon the anterior comrtrtfciQ£iting artery. More- over, the cjiains of opposite sidejg ■ communicate between these two "extremities in several' parts by means »f the 'fiervous''^pords that arise from\|hem. The synlpatliftic # ganglia are located "thus; CephaiJre, 4; Gervi