: 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/cu31 924031 26801 8 Cornell University Library arV18001 A manual of dissections of the human bod 3 1924 031 268 018 olin.anx A MANUAL OF DISSECTIONS OF THE HUMAN BODY. A MANUAL OF DISSECTIONS OF THE HUMAN BODY, FOR THE USE OF STUDENTS, AND MORE PARTICULARLY FOR THOSE PREPARING FOR THE HIGHER EXAMINATIONS IN ANATOMY. r > BY R? EfCARRINGTON, M.D. Lond., M.R.C.P., SENIOR DEMONSTRATOR OP ANATOMY, GUY'S HOSPITAL. LONDON: GEORGE BELL AND SONS, YORK STREET, COVENT GARDEN. 1881. /^cornellN [university! ^LIBRARY CHISWICK PRES5: C. WHITTINGHAM AND CO. TOOKS COURT, CHANCERY LANE. PREFACE. It has not been found possible in the arrangement of these dissections to classify them under the usual headings of Head and Neck, Upper extremity, Abdomen, and Lower extremity, because many of them would have been included under two or even more of these : in fact, they have often been specially planned with this object, so as to include the border lines of parts which, as they belong strictly neither to one nor the other dissector, are often ne- glected entirely. Nevertheless, this order has been followed for the most part, and in cases where a dissection involves partly one part and partly another, it has as far as pos- sible been used as an intermediate link between the two,. It is taken for granted that the student should have care- fully dissected the whole body through before he turns his attention to special dissections. The steps outside the usual routine that are necessary to be taken to expose different structures, form a special feature of the higher anatomical examinations, and, indeed, are not absent from the more ordinary ones, and my experience of the past four years has shown me that students are often non- plussed as to the mode in which questions of this sort should be answered : it is to meet this difficulty, and also to assist those who may wish to carry their anatomical VI PBEFACE. knowledge further than the usual dissecting-room course would allow them, that this work has been published. I am thoroughly convinced that it is well nigh impos- sible to accurately answer many of the questions that are asked in the higher examinations, except they have pre- viously been worked out practically, and am strongly of opinion that special arrangements should be made to meet the requirements of candidates for these tests. If a subject were allotted to four instead of eight dissectors, I think, by mutual arrangement and consultation between themselves, they might each of them perform many special dissections, and might collectively work out many others. The present manual is the result of special work during the conduct for the past two years of the anatomical class for the first M.B. examination of the University of Lon- don. I have been greatly assisted by Messrs. ~W. A. Lane and J. A. P. Price, Assistant Demonstrators at Guy's Hospital, and to them I desire to express my great obligations for thorough and painstaking work in the pro- section for this class. The principle that has been followed throughout, has been to perform the dissection with the least possible de- struction of surrounding parts compatible with the full ex- posure of the structure under consideration. The skin incisions have been carefully planned with this object, and I may incidentally remark that this is often one of the most difficult steps of the dissection, and that further, owing to the retraction of the divided skin, the surface exposed will always be greater than that strictly included between the lines of incision. It will frequently happen that there are several preliminary steps to be taken before the actual point of the question is reached. Thus in a dissection to expose the Thoracic duct, the opening of the PKEFACE. VU Thoracic and Abdominal cavities may fairly be considered as not an essential part of the dissection, whilst in one to display the Internal Mammary Artery, a detailed account of the Thoracic and Abdominal parietes is evi- dently required. Students are often puzzled to know whether they are to consider such cavities as opened, or whether they are to write down every separate structure they divide in the course of the dissection. It is difficult to give an absolute answer, but in the absence of specific information from the examiner himself, much will depend upon the amount of time allowed them to write their paper. It may, however, be taken for granted that nothing but naked-eye anatomy is required. The plan that has been followed in arranging and writing out the various dissections is this: — 1. The position of the body, or part, is indicated. 2. The requisite skin incisions have then been stated carefully. 3. The dissection has been divided into stages numbered I., II., III., &c, and the different steps of each stage have been indicated by the small letters a, b, c, d, &c. 4. After each stage short accounts numbered 1, 2, 3, 4, &c, of the structures exposed have been given, following as far as possible some definite direction, as from above downwards, or from side to side, and taking them in the order of bones, muscles, arteries, veins, nerves, &c. The student should avoid giving a bare list: he is not required to describe each structure that may be exposed, but he should indicate the relative positions of parts succinctly and distinctly. 5. When a structure to be exposed lies in two or Vrn PREFACE. more distinct regions each has, in some cases, been taken separately and indicated by the capitals A, B, C. I am painfully aware of the imperfections of this work, but trust that as each dissection has been actually per- formed, want of accuracy will not be one of them. No doubt the absence of plates is a striking deficiency, but in the presence of the beautiful atlases of Professor Ellis, and more recently that of Mr. Godlee, I am strongly of opinion that these will not be found necessary. My object, however, has been mainly to supply a little manual within the reach of all, which may be a guide to actual dissecting- room work. Sx. Thomas's Street, S.E. A MANUAL OF DISSECTIONS. A Dissection to Expose the Stetjctubes that aee seen on the removal oe the outee Wall oe the Oebit. Position. — The body lying upon its back, and the face rotated to the opposite side. I. Skin Incisions. 1. From the external angular process of the Frontal bone horizontally backwards an inch above the Zygoma, and parallel with it to a point one inch above its root. No. 1. 2. From just outside the outer canthus, obliquely downwards and backwards, over the Malar pro- cess, to a quarter of an inch below the lower B 2 A MANUAL OF DISSECTIONS. border of the Zygoma, and horizontally back- wards to its root. 3. A vertical incision joining the anterior extremi- ties of Nos. 1 and 2. Reflect the flap backwards, and expose the superficial fascia; clear this away, and the deep fascia over the muscles, and expose — 1. The Zygoma at the lower part of the surface ex- posed. 2. The lateral prolongation of the aponeurosis of the Occipito-frontalis muscle running down to be attached to the preceding. On the removal of this, the Temporal fascia is displayed. 3. The outer part of the Orbicularis palpebrarum muscle at the outer canthus. 4. The upper fibres of the Masseter muscle attached to the lower border of the Zygoma. 5. The anterior part of the Attrahens aurem muscle above the Zygoma, at the posterior part of the dissec- tion. 6. A small portion of the Parotid gland, covered by its fascia below the Zygoma at the posterior part. 7. Cutaneous arteries from — a. The Anterior Temporal above the Zygoma. b. The Transverse Facial below the Zygoma, o. The Lachrymal at the outer canthus. 8. Temporal branches of the Facial nerve passing up- wards over the Zygoma, and Malar branches run- ning over the Malar process. 9. The Temporal branch of the Temporo-malar nerve becoming cutaneous a finger's breadth above the Zygoma, and its communication with a Temporal branch of the Facial nerve. ORBIT THROUGH ITS OUTER WALL. 3 10. The Malar branch of the Temporo-malar nerve, cuta- neous over the Malar process, and communicating with a Malar branch of the Facial nerve. 11. A small twig of the Lachrymal nerve at the outer canthus. II. a. Remove the part of the Attrahens aurem muscle exposed. b. liaise the fibres of the Orbicularis palpebrarum muscle and turn it forwards, dissecting out more fully the Malar branch of the Temporo-malar nerve. c. Detach the Masseter muscle from the lower border of the Zygomatic and the Malar processes. d. Cut through the Temporal fascia from the upper border of the Zygoma. It will be found to consist of two layers, and between them will be found some fat, the Temporal branch of the Tem- poro-malar nerve behind the Frontal process of the Malar bone, and a small twig of the Middle Temporal artery. e. Saw through the Zygoma in front and behind and remove it, and clear away the fat beneath it in front of the Temporal muscle, extending down upon the Superior Maxilla. There will now come into view — 1. The part of the Malar bone previously covered by the Orbicularis muscle. 2. The tendon of the Temporal muscle attached to the Coronoid process of the lower jaw. 3. The Masseteric artery, vein, and nerve behind the Coronoid process, passing out through the Sigmoid notch, seen entering the muscle or divided. 4 A MANUAL OF DISSECTIONS. III. Remove completely the Temporal muscle from its origin and insertion as far as it is displayed. The Middle Temporal artery will be taken away with it, and there will then be exposed — 1. The posterior surface of the Orbital process of the Malar bone, the outer surface of the Ala major of the Sphenoid bone as low down as the Pterygoid ridge, the anterior part of the Squamous portion of the Temporal bone, and a small portion of the outer surface of the Superior Maxilla. 2. The upper head of the External Pterygoid muscle. 3 . The end of the second portion of the Internal Maxillary 'artery, and the Alveolar branch of the third portion upon the Superior Maxilla. 4. Twigs of the Lachrymal artery, passing through foramina in the Malar bone anastomosing with the Deep Temporal. 5. The anterior and posterior Deep Temporal arteries at the front and back parts of the Temporal fossa, and their veins running into 6. A portion of the Pterygoid plexus of veins upon the External Pterygoid muscle, joining in front with the Alveolar plexus. 7. The anterior and posterior Deep Temporal nerves with the corresponding arteries. 8. Oftentimes a small twig of the Masseteric nerve to the Temporal muscle behind the posterior Deep Temporal nerve. 9. The two Posterior Dental branches of the second division of the Fifth nerve lying upon the Superior Maxilla. 10. The temporal branch of the Temporo-malar nerve is again seen piercing the Malar bone. OEBIT THROUGH ITS OUTER WALL. 5 IV. a. Draw forwards the Orbicularis palpebrarum muscle, cut through the External Tarsal ligament, and, with the handle of the scalpel, separate the Dura mater of the Orbit from the outer wall, to pre- vent injuring it in the removal of the bone. b. Chip away with the chisel the Malar bone at the exit of the Malar branch of the Temporo-malar nerve, and follow this nerve through the bone. Its division into Temporal and Malar branches may thus be traced, and the nerve itself followed, into the inferior and outer angle of the Orbit. c. Now proceed to remove the portions of bone form- ing the outer wall of the Orbit with the chisel. This will be done piecemeal, but the following may be taken as the requisite incisions: — 1. A horizontal one at the upper part of the exposed surface, commencing in front at the suture be- tween the External Angular process and the Malar bone, and ending behind at the articulation be- tween the Squamous part of the Temporal bone and the Ala major of the Sphenoid bone. This is carried onwards until it reaches the Sphenoidal fissure behind. 2. A second horizontal one at the lower part of the dissection, commencing in front at the anterior part of the Malar process, passing through it, run- ning parallel with No. 1, and ending behind at a point corresponding to the upper. This opens up the Spbeno-maxillary fissure. 3. A vertical incision joining the hinder extremities of Nos. 1 and 2. The middle fossa of the skull is opened up slightly. b A MANUAL OF DISSECTIONS. There will now be exposed — 1. The Dura mater of the Orbit. 2. The Infra-orbital branch of the third part of the Internal Maxillary artery entering the Infra-orbital foramen, and the commencement of the Descending Palatine branches. 3. The second division of the Fifth nerve with the Infra- orbital artery, entering the same foramen, and the following branches ; the whole of the Temporo-malar and the upper portions of the two Posterior Dental. 4. Two or three twigs from Meckel's ganglion to the peri- osteum of the Orbit. Their source, however, is not seen. V. Remove the periosteum of the Orbit as far back as the Sphenoidal fissure ; here it will be seen to be conti- nuous with the Dura mater of the skull. Clear away fat. There will now be exposed — 1. The Eye-ball. 2. The External and Inferior Recti muscles outside and below the eye-ball respectively, and the Inferior Oblique muscle passing below the Inferior, and in- ternal to the External Rectus muscle. 3. The Lachrymal gland at the upper and outer part of the orbit. 4. The Lachrymal nerve and artery above, the nerve joining with the Temporo-malar. 5. The nerve from the Third to the Inferior Oblique muscle entering its posterior border. THE VERTEBRAL ARTERY. 7 A Dissection to Expose the Vertebral Artery. Position. — A block should be placed under the shoulders, the head allowed to hang supported by a smaller one, and the face rotated to the opposite side on which the dissection is to be made. No. 2. I. Skin Incisions. 1. From immediately in front of the Mastoid process to the Sterno-clavicular articulation. 2. Transversely from the upper end of No. 1 to the Occipital tuberosity. 3. Transversely from the lower end of No. 1 along the upper border of the Clavicle for the inner half. Reflect the flap backwards and expose the superficial fascia containing — 8 A MANUAL OF DISSECTIONS. 1. The Platysma myoides muscle at the lower and front part. 2. Cutaneous arteries from: — The Posterior Auricular behind the ear. The Occipital upon the Occiput. The Ascending Cervical at the lower part through the Sterno-mastoid muscle. At the upper part of the same muscle from the Sterno-mastoid branch of the Occipital or External Carotid. From the Superficial Cervical over the Trapezius muscle. From the Suprascapular over the Clavicle. 3. The upper part of the External Jugular vein. 4. The Great Auricular nerve at its distribution over the Mastoid process, and the commencement of the branches to the Pinna and face. 5. The Small Occipital nerve perforating the deep fascia near the skull. 6. The Great Occipital nerve perforating the fascia lata about half an inch from the anterior border of the Trapezius muscle, close to the Occiput. 7. The Third Occipital nerve perforating behind the dis- tribution of the Great, and running up to the Occi- pital protuberance. 8. Cutaneous filaments from the third and fourth Cer- vical nerves ramifying over the lower part of the Trapezius mnscle. 9. Filaments of the Superficial Cervical nerve perforating the Platysma muscle over the centre of the Sterno- mastoid muscle. II. Remove the Platysma muscle, dissecting out at the same time the Sternal and Clavicular branches of the third and fourth Cervical nerves. The External Jugular Vein will now be displayed as far as the point of its perforation of the deep fascia at the lower part of the posterior triangle, THE VERTEBRAL ARTERY. V III. Clean away the fascia lata, preserving and dissect- ing further the preceding vessels and nerves to the extent that this is possible without removal of muscles. There will now be exposed — 1. The Sterno-mastoid muscle in front. 2. The anterior portion of the Trapezius muscle be- hind. 3. In the angular interval between the preceding muscle at the skull, either a dense fascia or the Complexus muscle. 4. The Splenius capitis muscle, and the slip of the Splenius colli to the transverse process of the Atlas. This muscle runs downwards and back- wards highest of those forming the floor of the posterior triangle. 5. The attachments of the Levator anguli scapulae muscle to the upper three or four Cervical transverse prooesses. 6. The Scalenus medius muscle immediately below the preceding, and behind the Sterno-mastoid muscle. 7. The posterior edge of the Scalenus anticus muscle, in the case of a narrow Sterno-mastoid muscle. 8. The posterior belly of the Omo-hyoid muscle crossing the Scalenus medius obliquely at the lower part. 9. Branches of the Superficial and Ascending Cervical arteries in the upper part of the posterior triangular space. 10. The Transverse Cervical artery crossing from beneath the lower part of the Sterno-mastoid muscle and passing under the Omo-hyoid muscle. 11. The third part of the Subclavian artery turning over the first rib, and the Posterior Scapular artery when it is a branch of this part of the vessel. 10 A MANUAL OF DISSECTIONS. 12. The whole length of the External Jugular vein and its sinus joined below by the Transverse Cervical, Suprascapular and Posterior Jugular branches, and communicating over the Clavicle with the Cephalic vein, and over the Sterno-mastoid muscle with the Anterior Jugular vein 13. The Posterior Auricular nerve, artery, and vein be- hind the Pinna. 14. The Great Auricular nerve turning round the poste- rior border of the Sterno-mastoid muscle at its upper part and dividing into branches for the skin over the Mastoid process, Pinna, and the Parotid gland. 15. The Small Occipital nerve running up the posterior border of the Sterno-mastoid muscle. 16. The Great Occipital nerve now seen perforating the Trapezius muscle near its anterior border and ramify- ing over the Occiput accompanied by the Occipital artery and vein. 17. The Third Occipital nerve perforating the Trapezius internal to the preceding. 18. The Superficial Cervical nerve turning over the Sterno-mastoid muscle, and running transversely across beneath the External Jugular vein. 19. The superficial descending Sternal and Clavicular branches of the Cervical plexus. 20. The Spinal-accessory nerve crossing transversely from the upper third of the Sterno-mastoid muscle downwards and backwards to the Trapezius muscle. 21. A branch of the Cervical plexus from the third nerve to the Levator anguli scapulae muscle. 22. Branches from the third and fourth Cervical nerves to the Trapezius muscle. They accompany the THE VERTEBRAL ARTERY. 11 Spinal-accessory nerve and communicate with it, and some perforate the Trapezius muscle and supply the skin over it. These have been mentioned with the superficial fascia. 23. The Phrenic nerve in case the Scalenus anticus muscle is exposed. 24. The fifth, sixth, and seventh Cervical nerves form- ing part of the Brachial plexus. 25. The nerve to the Rhomboid muscle perforating the outer border of the Scalenus medius muscle at the upper part. 26. The Posterior Thoracic nerve perforating the same muscle lower down, and running down behind the Brachial plexus. 27. The Suprascapular nerve arising from the cord formed by the junction of the fifth and sixth nerves, and crossing the space transversely a little above the Clavicle. 28. The nerve to the Subclavius muscle running down over the third part of the Subclavian artery. 29. The branch from the Descendens noni nerve to the posterior belly of the Omo-hyoid muscle, passing from beneath the Sterno-mastoid to the lower border of the muscle it supplies. 30. The Glandulae concatenates along the posterior border of the Sterno-mastoid muscle, and a small piece of the Parotid gland immediately in front of the Mastoid process. IV. Remove now — a. The External Jugular vein and its branches. b. The Great Auricular, the Superficial Cervical, the Sternal and Clavicular, the Muscular to the Tra- pezius and the Spinal-accessory nerves. 12 A MANUAL OF DISSECTIONS. c. Take away the posterior portion of the Sterno- mastoid muscle by cutting through the mastoid and clavicular attachments and removing the piece. The branches of the second nerve to the muscle will be cut through. d. Detach the Trapezius muscle from its occipital attachment, and hook it well back. e. Cut through the Omo-hyoid and Splenius capitis muscles, and remove the attachments to the transverse process of the Atlas, of the Splenius colli, Levator anguli scapula, and Scalenus medius muscles. There will now be exposed — 1. The transverse process of the Atlas. 2. The posterior belly of the Digastric muscle running downwards and forwards from the deep surface of the Mastoid process. 3. The Stylo-hyoid muscle parallel with its anterior border. 4. The Trachelo-mastoid muscle at the upper part in- serted into the outer surface of the Mastoid process. 5. The Complexus muscle, behind the immediately pre- ceding muscle. 6. A small piece of the Superior Oblique muscle is seen running up from the transverse process of the Atlas between the Trachelo-mastoid and Complexus muscles. 1. The Rectus capitis anticus major muscle is seen in front arising and running upwards from the anterior tubercles of the transverse processes of the third, fourth, fifth, and sixth Cervical vertebrae. 8. The Scalenus anticus muscle is seen below the Rectus muscle inserted into the same points. THE VERTEBRAL ARTERY. 13 9. A further piece of the Splenius colli muscle is seen by the removal of the Sterno-mastoid muscle. 10. The Longus colli muscle is seen on the front of the vertebral column anterior to the Rectus anticus major, and Scalenus anticus muscles. 11. Above the Manubrium the outer margin of the Sterno-hyoid muscle is displayed. 12. The Common Carotid artery, its Internal and Ex- ternal branches, and the Occipital offset of the latter. 13. The first part of the Subclavian artery and the foil owing branches : — Thyroid axis giving off Trans- verse Cervical and Suprascapular offsets, which run backwards over the Scalenus anticus muscle, and the Inferior Thyroid running upwards beneath the Common Carotid, having given off previously the Ascending Cervical branch which passes upwards in the interval between the Scalenus anticus and Rectus anticus major muscles, and sends numerous offsets to the posterior triangle. The commencement of the Internal Mammary branch of the first part of the Subclavian, but the Vertebral offset is not seen, as it lies under cover of its vein. 14. Branches of the Princeps Cervicis branch of the Occipital artery are seen superficial to the Complexus muscle. 15. The Internal Jugular vein parallel with and outside the Common Carotid artery, and its Occipital branch. 16. The part of the Anterior Jugular vein which lies below the Sterno-mastoid muscle. 17. The upper part of the Subclavian vein and its Ver- tebral branch. 18. The Thoracic and right lymphatic ducts opening into 14 A MANUAL OF DISSECTIONS. the junction of the Internal Jugular and Subclavian veins. 19. The first four Cervical nerves and their loops. Only, however, the lower part of the first loop is seen. The communications of the loop of the Atlas with the Hypoglossal nerve, and the Superior Cervical gan- glion. Branches of all the loops to the anterior Recti muscles. 20. The Hypoglossal nerve, the Descendens noni branch. The Communicans noni branches of the second and third Cervical nerves pass over or under the In- ternal Jugular vein, and join the Descendens in a loop. The branch from this loop to the Sterno- hyoid muscle is seen. 21. The lower two ganglia of the Sympathetic nerve, their connecting cord, and the lower part of the connection with the superior ganglion, the upper part of this trunk being overlapped by the Internal Jugular vein. The communication of the middle gan- glion with the fifth and sixth nerves, and of the in- ferior with the seventh and eighth. 22. The Phrenic nerve, and its communication with the nerve to the Subclavius muscle, lying upon the Scalenus anticus muscle. 23. The fifth, sixth, seventh, and eighth Cervical nerves, and the cord from the first Dorsal nerve to the Brachial plexus. V. Remove now — a. The upper part of the Complexus muscle with its nerves from the Suboccipital, and Great Occipital, and small arteries from the Vertebral entering its deep surface, and from the Princeps Cervicis overlying it. THE VERTEBRAL ARTERY. 15 , b. Detach the posterior belly of the Digastric muscle from its origin and turn it forwards, its nerve from the Facial will be divided. c. Cut through the origin of the Trachelo-mastoid muscle, its nerve from the Great Occipital will be cut. d. Detach the Scalenus anticus muscle from its origin and turn it back, the following structures will be cut through with it : — The Phrenic nerve and its communication with the Subclavian nerve. The Transverse Cervical, the Suprascapular, and As- cending Cervical arteries. e. Divide the Internal Jugular vein above and below, and remove the intermediate piece. f. Remove the Thoracic duct which crosses superficial to the Vertebral artery and vein. There will now be exposed — 1. The Occipital bone. The Mastoid process of the Tem- poral bone, and the transverse processes of the Cer- vical vertebrae. The posterior arch of the Atlas is seen in the floor of 2. The Suboccipital triangle bounded internally by the Rectus capitis anticus major, below by the Infe- rior Oblique, and above by the Superior Oblique muscles. 3. The Rectus capitis lateralis muscle is seen running up from the transverse process of the Atlas, and the Intertransverse muscles and ligaments between the transverse processes. 4. The Longus colli muscle is seen more fully in front of the vertebras. 5. The whole of the Subclavian artery is displayed be- low. Its Vertebral branch overlapped by the vein, 16 A MANUAL OF DISSECTIONS. and surrounded by branches of the inferior Cervical ganglion, is seen passing from the first part of the Subclavian artery to the foramen in the sixth Cer- vical transverse process ; and is again exposed in its upper part above, lying upon the posterior arch of the Atlas in the floor of the Suboccipital tri- angle. 6. A further part of the Occipital artery is seen above, and superficial to the same triangle a general anas- tomosis between the Frinceps and Profunda Cervicis arteries, and other twigs from the Vertebral. Mus- cular branches, and the occasional Mastoid branch of the Occipital may be seen. 7. The radicles of the Vertebral vein are exposed over- lying the Suboccipital triangle. The following are also exposed — 1. The Suboccipital nerve between the Vertebral artery and the posterior arch of the Atlas giving branches to both the Oblique and posterior Recti muscles. 2. The Great Occipital nerve (the internal branch of the posterior primary division of the second) turning round the lower border of the Obliquus inferior muscle. The anterior primary branch of the second nerve upon the transverse process of the Axis ex- ternal to the Vertebral artery. 3. A further portion of the Hypoglossal nerve closely united with the Vagus. 4. The Vagus nerve. 5. The Spinal-accessory nerve. 6. The Superior Cervical ganglion. 7. The loop of the Atlas and its communications with the Hypoglossal and Vagus nerves and the superior ganglion of the Sympathetic nerve. THE VERTEBRAL ARTERY. 17 VTI. a. Cut away the Superior Oblique muscle entirely, and detach the Inferior Oblique muscle from the transverse process of the Atlas and turn it down. b. Remove the Eectus lateralis, the Eecti antici major and minor muscles, and detach the Longus colli muscle from the third, fourth, fifth, and sixth transverse processes. c. Chip away with the chisel the anterior tubercles of the Cervical transverse processes and small portions of the bone behind, leaving the posterior tubercles ; in this way the vertebral foramina will be opened up. d. Remove with the chisel and small saw a piece of the Occipital bone by the following incisions : — 1. From the Occipital tuberosity vertically to the foramen magnum, behind. 2. From the Occipital tuberosity transversely to the articulation of the Mastoid portion of the Temporal bone with the Occipital. 3. Vertically down from the anterior end of No. 2, through the middle of the Occipital Condyle, to the foramen magnum. e. Divide the Capsular, Posterior Occipito-atloid and Check ligaments of the same side, and the first process of the Denticulate ligament. f. Take away a small piece of the lower part of the lateral lobe of the Cerebellum. g. Remove the Vertebral vein, which conceals the artery both below and in the foramina of the transverse processes. The Vertebral artery is now exposed in its whole course, c 18 A MANUAL OF DISSECTIONS. with its Anterior and Posterior Spinal, Meningeal, and the commencement of the Posterior inferior Cerebellar branches. It is seen lying in the foramina in the transverse pro- cesses of the Cervical vertebrae surrounded by branches of the Sympathetic nerve derived from the Inferior Cervical ganglion, and having the Anterior primary branches of the Cervical nerves behind it, except the first, which is internal, and the second, which is external to it. Within the skull the eighth and ninth nerves pass over it, and the Spinal- accessory is separated from it by the first process of the Ligamentum Denticulatum. A Dissection to Expose the Otic Ganglion and the Cartilaginous portion of the Eustachian Tube. Position. — The body lying upon the back, and the face rotated to the opposite side. I. Skin Incisions. 1. Along the upper margin of the Zygoma, from the anterior extremity of the origin of the Masseter muscle to the posterior part of the Condyle of the jaw. 2. Vertically along the anterior margin of the Masseter muscle to a point midway between the origin and the lower margin of insertion. 3. From the lower end of No. 2 transversely back- wards to the posterior margin of the Ramus of the jaw. Reflect the flap backwards, and expose the superficial fascia. THE EUSTACHIAN TUBE. 19 II. Clear this away and expose — 1. The Zygoma. 2. The Temporal fascia just at its attachment, to the Zygoma. 3. The Parotid fascia, that covering the Masseter muscle, and a small piece of the Buccal fascia in front. 4. The Temporal, Malar, and Infraorbital branches of the Facial nerve emerging from the Parotid gland. 5. The Transverse Facial artery and vein parallel with and below the Zygoma. No. 3. 6. The duct of the Parotid Gland below the artery, with branches of the nerve above and below it. III. Remove the preceding structures and expose — 1. A portion of the neck of the jaw, the Capsular and the External lateral ligaments of the articulation. 2. The Masseter muscle running downwards and back- wards from the Zygoma. 3. A small piece of the Buccinator muscle at the anterior margin of the preceding. 4. Emerging from the front border of the Masseter, the , Buccal branch of the fifth nerve. 5. The Buccal branch of the Internal Maxillary artery accompanying it. 20 A MANUAL OF DISSECTIONS. 6. The Anterior Internal Maxillary vein also issuing from beneath the Masseter muscle. 7. The Parotid gland upon the Masseter mnscle. IV. a. Divide both layers of the Temporal fascia at their attachment to the Zygoma. b. Remove the anterior part of the Parotid gland, the Socia parotidis, and the included part of the Facial nerve. c. Remove the Masseter muscle within the limits of the skin incision. In doing this its nerve from the third division of the Fifth, with its artery from the Internal Maxillary, and its vein to the Pterygoid plexus will be divided. d. Saw through the Zygoma, in front and behind, and remove the included piece of bone. The following structures are now exposed — 1. The upper half of the Ramus, and the Coronoid pro- cess of the jaw, a portion of the upper Alveolus, and the tuberosity of the Superior Maxilla. 2. The Posterior Dental nerve and artery, and the Alveolar plexus of veins lying upon the Superior Maxilla. 3. Part of the fleshy fibres and the insertion of the Tem- poral muscle into the Coronoid process. 4. The Buccal nerve, artery, and vein in front of the Temporal tendon. 5. The divided end of the Masseteric nerve, artery, and vein behind the tendon emerging from the Sigmoid notch. 6. The Auriculotemporal nerve at the posterior part, running vertically upwards. 7. The Temporal artery and vein with the preceding. THE EUSTACHIAN TUBE. 21 V. a. Divide the jaw through its neck, and again trans- versely across the Ramus halfway down. b. Cut through the Temporal muscle parallel with the upper skin incision. c. Remove the piece of bone with the muscle attached. Branches of the Buccal nerve and occasionally others from the Masseteric nerve to the Temporal muscle will be divided, and the Middle Temporal artery removed in its substance. There will now be exposed — 1. The External Pterygoid muscle lying transversely. 2. The Internal lateral ligament passing vertically down beneath the Ramus. 3. The Internal Maxillary artery, 1 at firBt crossing the ligament, then lying upon the muscle, and pass- ing between its two heads in front. Whilst the artery is lying upon the External Pterygoid muscle, it is seen giving off the anterior and posterior Deep Temporal, the Masseteric, Buccal, and Pterygoid branches ; and whilst upon the ligament the In- ferior Dental offset. 4. Lying upon the muscle the superficial part of the Pterygoid plexus of veins, joining in front with the Alveolar, receiving branches corresponding to those of the artery, and forming behind the Internal Maxillary vein which joins the Temporal. 5. Issuing above the upper border of the muscle, the. anterior and posterior Deep Temporal nerves. Pass- ing between the two heads, the Buccal nerve and the anterior part of the Internal Maxillary artery ; 1 "When it occupies the normal position superficial to the Ex- ternal Pterygoid Muscle, otherwise it is beneath it. 22 A MANUAL OF DISSECTIONS. and emerging from the lower border the Dental and Gustatory nerves, the latter being anterior. The Buccal nerve is frequently seen to join the anterior Deep Temporal, and the posterior Deep Temporal may be derived from, the Masseteric nerve. VI. a. Divide the Internal Maxillary artery in front and behind, cut through its branches, and remove it. b. Disarticulate the jaw. Remove the External Ptery- goid muscle from its origin, and take it away ; dividing at the same time the Buccal nerve. c. Divide carefully with the chisel the External Ptery- goid plate and remove it, cutting the fibres of origin of the Internal Pterygoid muscle from its deep surface. There will now be exposed — •■ 1. The Internal Pterygoid muscle passing obliquely downwards and backwards. 2. The ascending branches of the first part of the In- ternal Maxillary artery, before hidden by the jaw ; viz., Middle Meningeal, running up to the Foramen Spinosum, the Small Meningeal, often a branch of the preceding to the Foramen Ovale, the Tympanic branch backwards to the Glasserian fissure. 3. The deep part of the Pterygoid plexus of veins. 4. The Third division of the Fifth nerve issuing from the Foramen Ovale and dividing into an anterior or motor part from which the anterior and posterior . Temporal, the divided Masseteric and Buccal nerves, and the branch to the External Pterygoid muscle may be traced; and a posterior or motor-sensory part from which the Auriculo-temporal with its two roots embracing the Middle Meningeal artery, and THE EUSTACHIAN TUBE. 23 the Dental and Gustatory branches may be followed. A communication between the Auriculo-temporal and the Facial nerves may be seen. 5. The Chorda Tympani nerve issuing from the canal of Huguier and joining the Gustatory nerve. VII. Divide the Internal lateral ligament. Cut through the Dental and Gustatory nerves, and reflect them carefully upwards. There will now be seen — 1. The nerve to the Internal Pterygoid entering the posterior border of the muscle. -7 ft 2. The Otic ganglion lying upon the .mrwfug, closely , connected with its nerve. 3. The Tensor palati muscle lying beneath it. 4. The branch of the Otic Ganglion to the Tensor palati, and that to the Tensor tympani muscle passing backwards. 5. The Lesser Petrosal nerve coming through the spine of the Sphenoid, and the communication with the Sympathetic nerve on the Middle Meningeal artery may be traced to the ganglion. VIII. Divide— a. The Internal Pterygoid muscle, at its attachment to the Ramus, and remove it. Its nerve will be cut through. b. The Great and Small Meningeal arteries, and the Pterygoid veins, and clear them away. c. The Third division of the Fifth Nerve, and remove it entirely. The Chorda Tympani nerve will be destroyed. d. Cut through the Tensor palati muscle from its origin, and at the point where it turns round the Hamular process, and take it away. The outer surface of the cartilaginous portion of the 24 A MANUAL' OF DISSECTIONS. Eustachian tube is now fully exposed, from the retiring angle between the Squamous and Petrous portions of the Temporal bone, to its attachment to the Internal Ptery- goid plate. The following structures are also seen — 1. The Levator palati muscle arising from its lower membranous part, and passing over 2. The arched upper border of the Superior Constrictor, which muscle arises from the lower third of the In- ternal Pterygoid plate. 3. Lying upon the preceding the Ascending Pharyngeal artery, dividing into the following branches : — one following the tendon of the Tensor palati muscle, one passing over the upper border of the Superior Constrictor muscle, another to the Middle Lacerated foramen, and sometimes one to the Anterior Condy- loid. A Dissection to Expose the Hypoglossal Nerve in the Extra-Cranial part op its course. Position. — The body lying upon its back, the face rotated to the opposite side to that upon which the dissec- tion is to be made, the jaw pulled well upwards, so as to extend the head, and the Hyoid bone drawn downwards by hooks. I. Skin Incisions. 1. From the middle line in front along the base of the jaw, and the posterior border of the Ramus as high as the Zygoma, then backwards, winding round THE HYPOGLOSSAL NERVE. 25 the attachment of the Pinna, to the Mastoid process. Transversely from the middle line opposite the Hyoid bone, outwards to a point vertically below the hinder end of No. 1. No. 4. 3. Join the anterior ends of Nos. 1 and 2 by a vertical incision along the median line. Reflect the flap backwards, and there will be exposed the superficial fascia, containing — 1. Twigs of the Posterior Auricular artery behind the Pinna. 2. An Anterior Auricular artery to the front of the Pinna. 3. Cutaneous offsets of the Submental branch of the Facial artery below the jaw. 4. The Great Auricular nerve crossing the Sterno- mastoid muscle obliquely towards the Pinna, and dividing into Mastoid, Auricular, and Facial branches. 26 A MANUAL OF DISSECTIONS. 5. Cutaneous twigs of the upper branch of the Super- ficial Cervical nerve beneath the jaw. II. a. Remove the superficial fascia, and expose the Platysma myoides muscle running up to the base of the jaw, from the middle line nearly as far back as the angle. Take this away, and expose the fascia lata, which should then be cleaned away. In the course of this dissection, the upper branch of the Superficial Cervical nerve, and the Infra-maxillary branch of the Facial nerve will come into view. They will both be found to lie at first, beneath the deep fascia, and to communi- cate with one another ; they then perforate the fascia, and again communicate, and then the former is distributed to the skin, and the latter to the Platysma muscle. They may now be re- moved. When this is done, the Parotid and Sub- maxillary glands will come into view, with many other structures. It will be convenient to take the glands away at once, to avoid enumerating the same parts twice over. b. In removing the Parotid gland, the following structures will be found in its substance from the surface inwards : — 1. The commencement of the Facial nerve, and its division into Cervico-facial and Temporo- facial offsets. When the gland is completely removed the exit from the Stylo-mastoid foramen will be seen, and the Posterior Auricular, and the branches to the Digastric THE HYPOGLOSSAL NERVE. 27 and Stylo-hyoid muscles observed coming off close to the point of exit. The nerve should be removed. 2. The External Jugular vein and the com- mencement of its communications with the Internal Jugular and Facial veins. These and the Internal Maxillary vein should be divided, and the External Jugular removed. 3. The External Carotid artery, its Anterior and Posterior Auricular, Temporal, and In- ternal Maxillary branches, and the Trans- verse Facial offset of the Temporal. All these should be divided, and the trunks re- moved. c. In removing the Submaxillary gland, the Facial vein will be found passing over it, and should be cut away ; the Facial artery traversing it, or grooving its deep surface and giving off in its substance the Submental and Submaxillary off- sets. It also should be divided above and below, and these branches taken away. The following structures will now be exposed — 1. The body of the Hyoid bone and the greater Cornti, at the lower part of the dissection. 2. Part of the Sterno-Mastoid muscle behind, running up to the Mastoid process. 3. Both bellies and the tendon of the Digastric muscle. The posterior belly running downwards and for- wards from beneath the Sterno-mastoid muscle, the tendon attached by areolar tissue to the body of the Hyoid bone, and the anterior belly, running thence, 28 A MANUAL OF DISSECTIONS'. upwards and forwards, to the lower jaw close to ' the Symphysis. 4. The Stylo-hyoid muscle parallel with, and in front of the posterior belly of the Digastric muscle, seen splitting below for the tendon of the latter to be attached to the body of the Hyoid bone. 5. The Mylo-hyoid muscle, running up from the body of the Hyoid bone to the lower jaw. 6. The Hyoglossus muscle, seen in small part behind the Mylo-hyoid, and running up beneath it. 7. The under surface of the angle of the jaw can be seen, and the Internal Pterygoid muscle lying upon it. 8. The External Carotid artery, and the following branches : the commencement of the Occipital and Lingual : the origins of the divided Temporal, Pos- terior Auricular, and Facial. The last may be seen giving off the Tonsillar and Inferior Palatine offsets. 9. Owing to the retraction of the Sterno-mastoid muscle on the division of the process of fascia, extending from the angle of the jaw to its anterior border, the Internal Carotid artery, and the 10. Internal Jugular vein behind it. 11. The Mylo-hyoid branch of the Inferior Dental artery lying upon its muscle. 12. Radicles of the Anterior Jugular vein beneath the chin. 13. The Vagus nerve between the Internal Carotid artery and the Internal Jugular vein. 14. The branch of the Inferior Dental nerve, to the Mylo-hyoid and Digastric muscles. The small twig supplying the latter, however, being traceable be- fore the removal of the Submaxillary gland. 15. The Hypoglossal nerve winding round the Occipital THE HYPOGLOSSAL NERVE. 29 artery, and then running transversely forwards beneath the posterior belly of the Digastric muscle. The Descendens noni branch upon the External Carotid artery and the commencement of the twig to the Thyro-hyoid muscle. 16. Lymphatic glands of the Submaxillary region. III. a. Cut through the Mylo-hyoid muscle at its attach- ment to the jaw and the median raphe, and turn it downwards. b. Remove the exposed portion of the Sterno-mastoid muscle. c. Remove the whole of the Digastric and the Stylo- hyoid muscles. The nerves to these and the . preceding muscles will be divided. d. Divide the External Carotid artery below the point at which it is crossed by the Hypoglossal nerve. Cut through its Occipital offset, and the Inferior Palatine and Tonsillar branches of the Facial artery. Remove the upper portion and pull down the lower. The Styloid process will now come into view, and the different structures attached to it. 1. The Stylo-glossus muscle, and Stylo-hyoid and Stylo- maxillary ligaments to the tip. 2. The origin of the Stylo-hyoid muscle from the centre of the outer surface, and 3. The Stylo-pharyngeus muscle from the inner side of the base. e. Cut the process through at the base with the forceps, and pull it down with the structures attached to it, having previously detached the Stylo-glossus muscle. 30 A MANUAL OF DISSECTIONS. f. Divide the Internal Jugular vein above and below, and remove it. The following structures will now come into view — 1. Above, the transverse process of the Atlas, and a small portion of the Rectus capitis lateralis muscle. 2. The Hyoglossus muscle running upwards from the body, and greater and lesser Cornua of the Hyoid bone to the side of the tongue. 3. The Stylo-glossus muscle at the upper border of the preceding muscle, divided posteriorly. 4. The Geniohyoid muscle in front, running up from the body of the Hyoid bone to the lower jaw. 5. The Genio-hyo-glossus muscle in front of the Hyo- glossus, and above the Genio-hyoid muscle. 6. The Middle Constrictor muscle, posteriorly. 7. Lying upon the Hyoglossus from above downwards : a. The Gustatory nerve, and the Submaxillary ganglion. 6. The deep part of the Submaxillary gland, with Wharton's duct running upwards and forwards from it, and passing beneath the preceding nerve. o. The Hypoglossal nerve lower down. It may now be seen in the whole of its course. At its commencement it is closely conjoined with the Vagus nerve, it then descends vertically, next turns forward on the Hyoglossus, and is finally distributed to the Hyoglossus, Stylo-glossus, Genio-hyoid, and Genio-hyo-glossus muscles. The commencement of the Descendens noni and Thyro-hyoid branches may also be seen, as well as the loops of communication with THE HYPOGLOSSAL NERVE. 31 the Gustatory nerve, at the anterior border of the Hyoglossus muscle. 8. Issuing from the anterior border of the Hyoglossus muscle is the Eauine branch of the Lingual artery, with its vein. 9. Passing under the posterior border of the same muscle are from above downwards — a. The Glosso-pharyngeal nerve, which may also be seen from the base of the skull downwards. 6. The Stylo-hyoid ligament, in the centre, c. The Lingual artery, lowest of all. 10. The Internal Carotid artery will be seen running up to the base of the skull, deep down in the hollow behind the Ramus of the jaw. 11. The Ascending Pharyngeal artery in front of, but parallel with the Carotid. 12. The Vagus nerve is seen passing down behind the artery, and giving off the Superior Laryngeal nerve beneath it, and the Pharyngeal branch either over or under the vessel. 13. The Spinal-accessory nerve is seen with the Vagus. It will probably be cut below by the removal of part of the Sterno-mastoid muscle. 14. The Superior Cervical ganglion of the Sympathetic nerve will be displayed. 15. The loop of the anterior primary branches of the first and second Cervical nerves in front of the transverse process of the Atlas. 16. Communications between this loop and the Vagus, Hypoglossal, and Sympathetic nerves are traceable. The preceding structures of the Submaxillary region may all be displayed if the preceding directions have been followed ; a more satisfactory view, may, however, be 32 A MANUAL OF DISSECTIONS. obtained ,if, after the reflection of the Mylo-hyoid muscle (Stage III.), the following steps be taken : — a. Sew the tip of the tongue to the Septum nasi. b. Divide the lower jaw and investing soft parts, in front near the Symphysis, and behind at the junc- tion of the body and Ramus, and turn the included piece upwards. In the anterior incision the following structures will be . divided : — 1. Skin. 2. Superficial and deep fasciae. 3. The Orbicularis oris muscle, and Inferior Coronary artery. 4. Depressor labii inferioris muscle. 5. Levator menti muscle. 6. The bone. 7. The mucous membrane of the mouth. In the posterior incision — 1. Skin. 2. Superficial and deep fasciae. 3. Facial vessels lying upon the bone. 4. Supra-maxillary, and Buccal branches of the Facial nerve. 5. Buccinator muscle. 6. Depressor anguli oris muscle. 7. Bone, and Inferior Dental nerve and artery in its substance. 8. The mucous membrane of the mouth, which should also be detached from the bone between the two incisions. If the bone be turned up in this way, the Sublingual gland and the Sublingual branch of thejjubjjfl. artery will in addition come into view, above the anterior border of the THE FIRST DORSAL NERVE. 33 Genio-hyo-glossus muscle. The Hypoglossal nerve may also be more fully traced into the substance of the tongue. A Dissection to Expose fully the first Dorsal Nerve. Position. — The body is to be supported by blocks upon the opposite shoulder to that on which the dissection is to be made. The shoulder to be well pulled down. I. Skin Incisions. A semilunar flap of skin, following the course of the first rib, is to be removed by the following incisions : — 1. From the seventh Cervical spinous process, to the lower border of the inner end of the Clavicle at its articulation with the Sternum. 2. From the second Dorsal spinous process, to the upper border of the second Costal cartilage at the Ster- num. 3. Vertical incisions joining the anterior and poste- rior ends of the preceding. The flap thus removed will cross in front the middle third of the Clavicle. There will now be exposed the superficial fascia, con- taining, passing from before backwards — 1. The Platysma myoides muscle over the Clavicle. 2. Arterial twigs over the Clavicle from the Supra- scapular. In the body dissected a branch from the Acromio-thoracic artery ascended over the bone. 3. A communication over the Clavicle between the Cephalic and the External Jugular veins, » 34 A MANUAL OP DISSECTIONS. The descending cutaneous branches of the Cervical plexus. The Supra-sternal branch oyer the inner end, and the Supra-clavicular over the middle of the Clavicle. The upper part of the Supra-acromial branches. No. 5. 5. The first Anterior Cutaneous nerve, artery, and vein. 6. The branch of communication from the Supra-clavi- cular to the second Anterior Cutaneous nerve. In this case it was with the first, and therefore the junction was seen. 7. By the side of the first Dorsal spine, the internal branch of the posterior primary division of the first THE FIRST DORSAL NERVE. 35 Dorsal nerve, with its corresponding artery and a radicle of the Dorsi-spinal veins. II. Remove the preceding structures and the fascia lata, and expose — 1. The Sterno-mastoideus muscle passing down to the inner third of the Clavicle, only a small portion of the outer border being seen. 2. Below this the Pectoralis major muscle, corresponding to the inner half of the same bone. 3. Posteriorly, and also at the outer side of the front aspect, the. Trapezius muscle. III. a. Within the limits of the skin incisions divide and remove the Pectoralis major muscle in front, and with it, branches of the External Anterior Thoracic nerve. b. Take away the portion of the Trapezius muscle exposed in the dissection. With it will be divided — 1. Branches of the Superficial Cervical artery and vein. 2. The Posterior Jugular vein. 3. Portions of the Spinal-accessory, and third and fourth Cervical nerves. There will now be exposed, passing from before back- wards — 1. A further portion of the inner end of the Clavicle. 2. Below this the fascia prolonged from the Pectoralis minor muscle, and the Costo-coracoid membrane and the structures perforating it, viz. : — The Acromio-Thoracic artery. The Cephalic vein. The External Anterior Thoracic nerve. 36 A MANUAL OF DISSECTIONS. Perhaps a small branch of the Superior Thoracic artery. 3. Above the Clavicle the third part of the Subclavian artery. 4. The Transverse Cervical branch of the first portion of the same artery is seen higher up, but the Supra- scapular offset is hidden by the Clavicle. Both these arteries have their veins with them. 5. Above the Subclavian artery are seen the cords of the Brachial plexus, and the following branches: The Supra-scapular, Posterior Thoracic, and the nerve to the Subclavius muscle. 6. Beneath the plexus and the Subclavian artery, the Scalenus medius and posticus muscles, the latter most external. 7. Still further back is seen the upper and inner angle of the Scapula, covered by the Supra-Spinatus muscle. 8. Ascending from the Scapula, and running upwards and forwards above the Brachial plexus, the poste- rior belly of the Omo-hyoid muscle. 9. The first digitation of the Serratus magnus muscle is seen, internal and posterior to this, above the upper border of the Scapula. 10. Still further back is the Levator anguli scapulae muscle ascending from the angle. 11. Interna] to it, and nearer the spine, the upper part of the Rhomboideus minor muscle. 12. The upper edge of the Serratus posticus superior muscle seen just above the Rhomboideus. 13. The Posterior Scapular artery, accompanied by its vein, is seen passing beneath the Levator anguli scapulae muscle, having previously given a branch over the dorsum Scapulae. Its continuity with the THE FIRST DORSAL NERVE. 37 Transverse Cervical artery beneath, the Omohyoid muscle is traceable. 14. The nerve to the Rhomboid muscles lies between the Rhomboideus minor and Levator angnli sca- pulae muscles, and may be found if they are sepa- rated from one another. IV. The dissection should now be commenced behind, and carried forwards. a. Remove the exposed part of the Rhomboideus minor muscle. The Serratus posticus superior muscle is seen beneath it, and the Posterior Scapular artery and vein between the two. b. Remove the Levator anguli scapulas muscle within the limits of the dissection. The nerve to the Rhomboidei muscles will be seen beneath it. c. Take away the exposed part of the Serratus posticus superior muscle, and remove at the same time the Posterior Scapular vessels, and the nerve to the Rhomboidei muscles. There will now be exposed, passing from the spinous processes outwards — 1. The tubercle of the first, and a considerable portion of the second rib. 2. The Splenius muscle in part, most internally. 3. The Transversalis colli muscle in part. 4s. The Cervicalis ascendens muscle in part, seen passing upwards. 5. The second Levator costse muscle passing from the transverse process of the first Dorsal vertebra downwards and outwards to the second rib, the ex- ternal ' branch of the posterior primary division of 1 In two dissections I have found this to be the case. -Both branches may however, be internal to the Levator costse muscle. 38 A MANUAL OP DISSECTIONS. the first Dorsal nerve passing out external to it, and the internal division internally. 6. Still more externally the Scalenus posticus muscle. Passing from below are — 7. The upper tendon of the Musculus accessorius into the first rib. 3. The highest tendon of the Longissimus dorsi muscle when attached to the first rib. V. a. Remove the preceding muscles as far as they are exposed in the dissection. In detaching the Transversalis colli muscle the Trachelo-mastoid will.be found beneath it, and should be taken away at the same time. The second Levator costse muscle may be retained in order to follow out more fully the nerves in relation with it. There will now be exposed — - A portion of the Complexus muscle along the median line. b. Eemove this and there will be seen — The Semispinalis muscle. c. Take away this and there will come into view — 1. The Multifidus spinse muscle. 2. Lying upon it the internal branches of the posterior primary divisions of the eighth Cer- vical and first Dorsal nerves. d. Clear away the Multifidus spinse muscle, and there will be seen — 1. The first rib at its inner part, the transverse process of the first Dorsal vertebra, and part of the second rib. 2. The posterior Costo-transverse ligament, be- THE FIRST DORSAL NERVE, 39 tween the first Dorsal transverse process and its rib. 3. The posterior part of the External Intercostal muscle. e. Divide the first Dorsal transverse process at its root with the chisel. Cut through the first rib at its neck, and again external to its tubercle. Cut through the first anterior Costo-transverse ligament which runs downwards from the first Dorsal transverse process to the second rib. Remove the included portions of bone. The posterior and middle Costo-transverse ligaments of the first rib will be taken away at the same time. The Superior Intercostal artery, which lies upon the neck of the first rib, will be divided ; but the Inferior Cervical ganglion of the Sympathetic, which is internal to it, will not come into view. f. Remove now the exposed External Intercostal muscle, and The trunk of the first Dorsal nerve and its division into anterior and posterior primary- branches will come into view. VI. Continue now the dissection forwards in order to trace out fully the anterior primary branch. a. Divide and remove the exposed portions of the Scalenus posticus, and Scalenus medius muscles. The latter muscle is taken away to trace the branch of the first Dorsal nerve which joins the eighth Cervical. b. Cut through the Clavicle in two places and remove its middle third with the Costo-coracoid membrane and the Subclavius muscle. c. Divide the Transversalis colli artery and vein, and the Supra-scapular artery and vein. 40 A MANUAL OF DISSECTIONS'. d. Cut through the cords of the Brachial plexus, and the Supra-scapular branch. e. Remove the first digitation of the Serratus magnus muscle, the fascia over the External Intercostal muscle, and the remaining portion of the muscle itself. The anterior primary branch of the nerve may now be fully traced. N.B. — The nerve in the posterior part of its course lies underneath the first rib, and this must be lifted up, or better, the outer border may be chipped away to the necessary extent. A Dissection of the Posterior Surface of the Coed in the Cervical Eegion. Position. — The body lying on its face, the shoulders supported by blocks, and the head hanging forwards. I. Skin Incisions. 1. A vertical one along the middle line, the upper limit of which is the central point of a line encir- cling the neck at the level of the apices of the Mastoid processes, and the lower the first Dorsal spinous process. 2. Transverse incisions above and below for two inches on each side. Reflect the flaps to the sides and expose the superficial fascia containing — 1. Small cutaneous branches from the Superficial Cervical artery on the outer side, and from the Profunda Cervical artery with the nerves described under No. 4. THE SPINAL COED IN THE NECK. 41 2. Veins corresponding to the preceding arteries, and others along the spines connected with the Dorsi- spinal. 3. At the outer parts of the surface exposed cutaneous twigs from the third and fourth Cervical nerves supplying the skin over the Trapezius muscles. 4. Along the Spinous processes the inner branches of the posterior primary divisions of the third, fourth, and fifth Cervical nerves, the third sending a branch up to the Occiput. No. 6. II. Remove the preceding and the fascia lata, and expose — 1. The Trapezii muscles running up above to the inner third of the superior curved lines, each attached to all the Cervical spines by means of the ligamentum nucha. 2. Small portions of the Sterno-mastoidei muscles at the extreme upper and outer parts. 3. A small portion of the Splenius capitis muscle between the two preceding on either side. III. Cut through and remove the Trapezius muscle on each side as far as it is exposed. With it there will be re- 42 A MANUAL OF DISSECTIONS. moved the Spinal-accessory nerve and branches from the third and fourth Cervical nerves, together with offsets of the Super- ficial Cervical artery. The following structures will now be seen on both sides : — 1. The Complexus muscle highest of all, inserted into the space between the curved lines of the Occipital bone. 2. Below this, the Splenius muscle, arising as far as it is possible to make out in this dissection, from the spines of the first Dorsal and the seventh Cervical vertebrae and the ligamentuin nuchas up to the third vertebra, and splitting above into two portions, the upper one of which goes to the head (S. capitis), and the lower to the posterior tubercles of the upper three or four Cervical transverse processes (S. colli). 3. Below the Splenius the Ehomboideus minor muscle, running downwards and outwards from the seventh Cervical and first Dorsal spines. 4. The Serratus posticus superior muscle has the same origin as the preceding, and lies beneath it; its superior border showing above it however. 5. The origin of the Levator anguli scapulas muscle, from the upper three or four posterior tubercles of the Cervical transverse processes is seen on the outer side of the Splenius. 6. Between the Levator- anguli scapulas and the Ehom- boideus minor, and below the Splenius muscles is a triangular interval, in which some tendinous slips of the Cervicalis ascendens and Transversalis colli muscles appear, the latter being internal. 7. Lying upon the Complexus muscles at their extreme THE SPINAL CORD IN THE NE"CK. 43 upper and outer parts are the Occipital artery and vein, and lower down on the Splenitis muscle branches of the Superficial Cervical artery and vein, and the Posterior External Jugular vein. 8. Lying upon the Complexus above the Splenius muscle, the internal branches of the posterior primary divisions of the second and third Cervical nerves and their communications (Great and Third Occi- pital nerves). immv. a. Detach the Rhomboideus minor and the Serratus posticus superior muscles of both sides and take them away. The nerves to the Rhomboid, and also those supplying the Serrati muscles, will be divided. b. Hook well aside the following muscles of each side : — Levator anguli scapulae, Cervicalis ascen- dens, and Transversalis colli. c. Remove the Splenii muscles as far as they are ex- posed in the space dissected. Their nerves from the external branches of the posterior primary divisions of the Cervical nerves will be seen and divided on their deep surface. There will now be exposed — 1. The tubercle of the first rib, internal to the retracted Transversalis and Cervicalis muscles on each side. 2. The Complexus muscles lying in the vertebral groove, and reaching above from the Occiput to the lower extremity of the space. The inner division called Biventer cervicis is apparent. 3. The Transversales and Cervicales muscles of both sides more fully. 4. The Trachelo-mastoid muscles on either side, inside 44 A MANUAL OF DISSECTIONS. the two immediately preceding muscles, arising from the Cervical articular processes from the fourth to the seventh inclusive, and inserted into the Mastoid processes. All their origin however, is not seen. 5. The Occipital vessels, lying upon the Complexus muscle of each side at its extreme upper part, and offsets of the Princeps Cervicis branch running down superficial to the muscle. 6. The same branches of the second and third Cervical nerves already mentioned. 7. The nerves to the Splenii muscles from the posterior primary branches of the Cervical are seen entering their deep surface. V. a. Cut through and remove the Complexus muscles from their origins and insertions. The former ; as is displayed in this dissection is from the trans- verse processes of the first Dorsal and seventh Cervical vertebrae, the spine of the seventh, and the articular processes of the fourth, fifth, and sixth Cervical vertebras ; the latter ; is into the space between the two curved lines of the Occi- pital bone. The nerves to the Complexus from the Suboccipital, and internal branches of the posterior primary divisions of the second and third Cervical nerves, will be divided on re- moving the muscle. There will now be exposed — 1. The articular processes of the second, third, fourth, fifth, and sixth Cervical vertebrae. 2. The ligamentum nuchse now displayed by the re- moval of the various muscles. THE SPINAL COED IN THE NECK. 45 3. The Suboccipital triangle, bounded internally by the Rectus capitis posticus major muscle, below and externally by the Inferior Oblique muscle, and above and externally by the Superior Oblique muscle. In its floor is the posterior arch of the Atlas. 4. The Semispinales muscles, running from the trans- verse processes to the spines as high as the second vertebra. 5. Above and external to the processes of the Semi- spinalis muscle, passing to the second and third spinous processes, is seen a small piece of the Multi- fidus spinse muscle on either side. 6. Lying upon the arch of the Atlas in the floor of the triangle is seen the Vertebral artery. 7. Upon the Semispinales, beneath the nerves to be mentioned, the Profunda Oervicis branch of the Superior Intercostal artery running np to join in a general anastomosis over the Suboccipital triangle, with branches of the Vertebral and Princeps Cervicis arteries. 8. The origins of the Vertebral vein, and sometimes the Posterior Condyloid vein in the triangle. The Profunda Cervicis vein with the corresponding artery. 9. The Suboccipital nerve, and the internal divisions of the posterior primary branches of the second, third, fourth, and fifth Cervical nerves. The first, second, and third communicate and form Oruveilhier's plexus. The Suboccipital nerve lies beneath the Verte- bral artery wpon the arch of the Atlas and supplies both the Eecti postici and Oblique muscles and the Complexus ' muscle. The great Occipital nerve turns round the lower border of the Inferior Oblique 46 A MANUAL OF DISSECTIONS. muscle. The third, fourth, and .fifth nerves course inward over the Semispinalis to become cutaneous by the Spines ; these are seen at their junction with the external branches. 10. The external branches of the second, third, fourth, fifth, sixth, seventh, and eighth nerves, emerging externally to the line of the articular processes of the Cervical vertebrae. These enter the following muscles : — Gomplexus,Transversalis colli, Trachelo- mastoid, and Cervicalis ascendens. 11. Branches from the Vertebral artery are seen with the last-mentioned nerves. VI. a. Remove now the Semispinals muscles, with the inner branches of the posterior primary divisions of the third, fourth, and fifth Cervical nerves lying upon them. This brings into view — 1. The seventh Cervical articular processes. 2. The inner branches of the posterior primary divisions of the sixth, seventh, and eighth Cervical nerves. In the dissection made, the corresponding branch of the fifth nerve passed beneath the Semi- spinalis muscle. b. Clear away the Multifidus spinse, the Rectus capitis posticus major and minor, the Superior and Inferior Oblique muscles of both sides. c. The anastomosis of Vertebral, Princeps, and Pro- funda Cervicis arteries. d. The origin of the Vertebral veins. e. Cruveilhier's plexus and the nerves forming it. f. The inner branches of the posterior primary divisions of the sixth, seventh, and eighth Cervical nerves. THE SPINAL COED IN THE NECK. 47 This will expose — 1. The laminae, articular, and spinous processes of the vertebrae as far as the first Dorsal, and the posterior arch of the Atlas. 2. The posterior Occipito-atloid and Atlo-axoid ligaments and the Capsular ligaments of the articular pro- cesses. 3. The Dorsi-spinal venous plexus lying upon the verte- bral laminee. VII. Saw through the posterior arch of the Atlas, and the laminae of the exposed vertebras internal to the articular processes on each side, and remove the pieces of bone together with the following structures : a. The Ligamentum nuchae. b. The Interspinals muscles. (There are none be- tween the Axis and Atlas.) c. The Interspinous ligaments. (Very slightly marked in the neck.) d. The Posterior Occipito-atloid, Atlo-axoid, and Liga- menta Subflava below the first two vertebras. e. The Vertebral artery, and the Suboccipital nerve. f. The Venae Dorsi-spinales. This opens up the Spinal canal and exposes — 1. The Dura-mater surrounded by loose areolar tissue. 2. The Posterior Longitudinal venous plexus lving upon the Dura-mater. VIII. Slit up the Dura-mater, with the parietal layer of the Arachnoid along the median line. This brings into view — 1. The visceral layer of Arachnoid with the Sub-arach- noid space and Pia-mater. 48 A MANUAL OF DISSECTIONS. 2. The posterior surface of the Spinal Cord. 3. The Posterior Spinal arteries, one in each side. 4. The Medulli Spinal veins, which are in the main two venous trunks, one on each side, united into a close plexus by intercommunicating branches. A Dissection of the Internal Mammary Artery. Position. — The body lying supine. I. Skin Incisions — 1. From the centre of the supra-sternal notch to mid- way between the umbilicus and Ensiform Cartilage. No. 7. 2. A transverse one parallel with and half an. inch above the upper border of the Sternum and Clavicle, THE INTERNAL MAMMARY ARTERY. 49 to the junction of the inner with the middle third of the latter. 3. Another transversely from the lower border of No. 1 to the tip of the tenth rib. Reflect the flap outwards and expose the superficial fascia containing — > * 1. The Platysma myoides muscle over the Clavicle. 2. The Supra-sternal and Supra-clavicular nerves passing over the Clavicle, and branches of the Supra-scapular artery with them. 3. The tipper eight Anterior Cutaneous branches of the Intercostal nerves along the median line. The cor- responding vessels from the Internal Mammary and Superior Epigastric trunks accompanying them. 4. A communication between the Supra-clavicular and second Anterior Cutaneous nerves. 5. 1 The anterior branches of the third, fourth, fifth, and sixth Lateral Cutaneous nerves. 6. Small cutaneous vessels are found in the wall of the abdomen, derived from the anterior portions of the Intercostals. II. Remove the Platysma muscle and the fascia lata, and expose — 1. The Sterno-mastoideus muscle, arising from the Manubrium Sterni and inner end of the Clavicle. 2. The Pectoralis major muscle, arising from the Clavicle and the true ribs from the first to the sixth inclu- sive. The interlaced aponeurosis of the muscles of opposite sides is also seen over the Sternum. 3. The aponeurosis of the Obliquus Externus muscle, and 1 The second Lateral Cutaneous nerve usually wants the an- terior branch (Ellis). It is, however, figured by Uenle. E 50 A MANUAL OF DISSECTIONS. the fleshy fibres attached to the ninth and tenth ribs. 4. Anterior branches of the Internal Mammary artery ramifying over the Sternum. III. a. Cut through the exposed attachment of the Sterno- mastoid muscle and turn it upwards. b. Remove the fleshy portion of the Pectoralis major muscle within the limits of the skin incisions, pre- serving the Anterior Cutaneous arteries and nerves, and observing additional muscular branches of the Internal Mammary artery in the intercostal spaces from the second to the sixth inclusive. c. Take away the anterior layer of the sheath of the Rectus muscle made up of the aponeuroses of the Obliquus Externus and Internus muscles, and further take away the aponeurosis and exposed fleshy portion of the Obliquus Externus muscle ex- ternal to this. d. Remove the upper part of the Rectus muscle, dissecting out the Superior Epigastric branch of the Internal Mammary artery which lies beneath it, with its vein. This artery is seen to enter the sheath of the muscle beneath the cartilage of the seventh rib. There will now be exposed — 1. The inner portion of the Clavicle, the side of the Sternum, and the Costal cartilages as far as the tenth. 2. The Sterno-hyoid and Sterno-thyroid muscles above the Manubrium and Clavicle. 3. The inner border of the Scalenus anticus muscle external to the preceding muscles. THE INTERNAL MAMMARY ARTERY. 51 4. The fascia over the Internal Intercostals, these muscles showing plainly through it ; and the anterior por- tions of the External Intercostal muscles. 5. A portion of the Obliquus Internus muscle outside the sheath of the Rectus muscle. 6. The Anterior Jugular vein crossing transversely above the Clavicle. The following structures between the Sterno-thyroid and Scalenus anticus muscles : — 7. A small portion of the first part of the Subclavian artery and the following branches. The Thyroid axis, the commencement of its Inferior Thyroid, and the Transverse Cervical and Supra-scapular offsets. The origin of the Internal Mammary branch is also seen. 8. The Phrenic nerve is seen on the Scalenus anticus muscle if the left artery is dissected ; on the right side this nerve is too far out. 9. The Vagus nerve, the commencement of its Recurrent Laryngeal and Inferior Cardiac branches, are to be seen upon the Subclavian Artery, if the right side is dissected ; on the left side this nerve is too deep. 10. The Ansae Vieusenii are seen crossing the first part of the right Subclavian artery. IV. Cut through the Sterno-hyoid muscle, and hook inwards the Sterno-thyroid muscle. Saw through the Clavicle at the junction of the inner with the middle third, and disarticulate the inner end from the Sternum by dividing the anterior and posterior Sterno-clavicular and Intercla- vicular ligaments. The interarticular fibro-cartilage will be removed, the Rhomboid ligament, the inner 52 A MANUAL OF DISSECTIONS. end of the Costo-Coracoid membrane, and a small piece of the internal portion of the Subclavius muscle cut through. Remove the upper and outer projecting angle of the Manubrium, c. Remove the fascia over the Internal Intercostal muscles, the anterior portions of the External and of the Internal Intercostal muscles. When this is done, the Internal Mammary artery will he seen in the intervals of the Costal cartilages about half an inch from the SternUm. It will be found to be giving off the Anterior Intercostal branches of the upper five or six spaces, two in each space, one running along the upper border of the rib, the other along the lower border of the rib above. These will be found to anasto- mose behind with the bifurcated Intercostal branches of the Aorta, similarly disposed as re- gards the rib. In the first or first two spaces, the Superior Intercostal artery will take the place of the Aortic Intercostal. In the lower spaces Anterior Intercostal arteries will be traced, but they will subsequently be found to arise from the Musculo-phrenic branch of the Internal Mam- mary artery, but this offset in its course out- wards and downwards to the ninth cartilage is hidden by the approximation of the seventh, eighth, and ninth cartilages. The Internal Mammary artery will be seen to lie upon the pleura above and the Triangularis sterni muscle below. The Intercostal nerves will also be seen in the spaces crossing superficial to it. Veins corresponding to all the arteries mentioned are seen. THE INTERNAL MAMMARY ARTERY. 53 d. Having thus traced the artery between the carti- lages, now remove the inner portions of the upper nine by cutting them through, externally in a line extending obliquely from the inner end of the divided Clavicle (one and a half inches from the Sternum) to the tip of the tenth rib ; and internally, disarticulate them from the breast-bone dividing the following : Anterior and Posterior Costo-sternal, Capsular, Interarticular of second joint and of third when present, and Costo- xiphoid ligaments. The last is between the Ensiform and seventh cartilages. The synovial .membranes will be of course destroyed. e. Now raise this portion of the chest-wall from above downwards, dividing on its under surface (1) the slips of the Triangularis sterni muscle to the Ensiform, and second, third, fourth, fifth, sixth, and seventh cartilages; (2) the attachments of the Diaphragm and Transversalis muscle from the sixth to the ninth, and still lower (3) the in- sertion of the Obliquus Internus muscle into the ninth rib, that part attached to the seventh and eighth being already removed. The upper part of the last muscle should now be reflected down- wards. This dissection should be done carefully, keeping the knife close to the inner surface of the chest-wall, to avoid a division of the artery. There will now be exposed, commencing from above — 1. The process of deep Cervical fascia beneath the Sterno- thyroid muscle, which should be cleared away. If the dissection is done on the left side. 2. The Internal Jugular and Subclavian veins joining 54 . A MANUAL OF DISSECTIONS. and forming the Innominate, only the beginning of which is exposed. The Vertebral and Internal Mammary veins will be seen joining the Inno- minate, and the Thoracic duct entering at the junction of the Jugular and Subclavian veins. 3. The lower , part of the Common Carotid artery beneath the preceding trunks. 4. The first part of the Subclavian artery, the Thyroid axis, and the commencement of its branches, and the origin of the Internal Mammary branch. 5. The Phrenic nerve crossing the Internal Mammary artery. Owing to the veins overlapping the arteries the Vagus nerve is not seen. If the dissection is Made on the eight side. 2. The veins as on the left, but they are more external and separated from the artery by an angular interval. The right Lymphatic duct is seen in- stead of the Thoracic. 3. The bifurcation of the Innominate artery into Subclavian and Carotid branches. 4. The right Vagus nerve, its Recurrent and Inferior Cardiac branches. 5. The Ansae Vieusenii. The Phrenic nerve lies too far out to be displayed on this side. 6. Lymphatic glands are seen at the root of the neck above the Manubrium. In the Thoracic Eegion. 7. The parietal Pleura is seen above, and the Trian- gularis sterni muscle below. 8. The Diaphragm is seen below. THE TRACHEA. 55 9. The seventh, eighth, and ninth Intercostal nerves are seen on the portion of the Transversalis muscle remaining, passing behind the Musculo-phrenic branch of the artery. 10. The whole of the Internal Mammary artery except the upper part is now seen, and this may be ex- posed by dividing the Subclavian vein and hook- ing inwards, the Innominate and Internal Jugular veins. This will expose in addition, if the dissection is done on the left side, the Vagus nerve and the Ansae Vieusenii, which were not previously seen. A Dissection to Expose the Anterior Surface oe the Trachea. Position. — Body supine, a block under the shoulders, and the head hanging back. I. Skin Incisions. (1.) Along the median line from the Cricoid cartilage to the level of the lower border of the third Costal cartilages at their junction with the Sternum. (2.) A transverse incision at the upper end for one inch on either side. (3.) A transverse incision at the lower end for three inches on either side. Reflect the flaps outwards and expose — 1. The superficial fascia. 2. The Platysma muscles over the inner ends of the Clavicles. 3. Branches of the Anterior Jugular veins perforating at a variable distance down the neck. 56 A MANUAL OF DISSECTIONS. 4. The inferior branch of the Superficial Cervical nerve at the lower part of the neck. 5. Twigs of the Supra-sternal and Supra-clavicular branches of the Cervical Plexus. 6. The communication of the Supra-clavicular with the second Anterior Cutaneous nerve. 7. Branches of the Supra-scapular artery passing over the Clavicle with them. No. 8. 8. Cutaneous branches from the Inferior Thyroid artery at the lower part of the neck. 9. The first Anterior Cutaneous artery from the Inter- nal Mammary sending small filaments to join them. 10. The Anterior Cutaneous arteries, veins, and nerves of the upper two spaces. 11. The anterior branch of the second Lateral Cutaneous nerve, when present. 12. Its corresponding artery. II. Remove all the preceding structures and expose the fascia lata of the neck and chest. . THE TRACHEA. 57 In taking away the Platysma, the Supra-clavicular and Supra-sternal nerves will be found beneath it above the Clavicle. III. Remove the fascia lata. In the middle line in front this will be found to present two layers, one between the anterior borders of the Sterno- mastoidei, and one between the corresponding borders of the Sterno-hyoidei. Some fat is found between these layers. There will now be exposed — 1. The inner portions of the Clavicles on either side, and the first two pieces of the Sternum ; the latter covered by the aponeurotic expansion of the Pec- torales muscles. 2. The Sterno-mastoidei muscles attached to the Cla- vicles. 3. The Sterno-hyoidei muscles. 4. Small portions of the Sterno-thyroidei muscles out- side the preceding. 5. Small portions of the Omo-hyoidei muscles at the upper and outer parts. 6. Small branches of the Supra-scapular arteries over the inner parts of the Clavicles. 7. Small branches of the Inferior Thyroid arteries above the Sternal notch. 8. Further portions of the Anterior Jugular veins, and a transverse branch of communication between the two, above the Sternal notch. 9. The Pectorales majores muscles. 10. Lymphatics. IV. Remove now — a. The Sterno-mastoidei muscles within the limits of the skin incisions. 58 A MANUAL OF DISSECTIONS. b. The Sterno-hyoidei muscles. c. The Sterno-thyroidei muscles. In doing this there will be seen immediately beneath the first muscle on each side — 1. A further portion of the Anterior Jugular vein. 2. The nerves to the Sterno-hyoidei and Sterno- thyroidei from the Ansa Hypoglossi entering the outer borders. d. Cut away the Pectorales muscles within the limits of the dissection. There will now be exposed from above downwards — 1. Processes of deep Cervical fascia beneath the Sterno- thyroidei muscles running to the Pericardium. 2. The lobes and isthmus of the Thyroid body. 3. The Trachea in the median line. 4. The (Esophagus at the root of the neck on the left side. 5. The Inferior Thyroid plexus of veins. 6. Branches of the Inferior Thyroid arteries. 7. The arteria Thyroidea ima when present. 8. The inner margins of the Scaleni antici muscles on either side. 9. The Omo-hyoidei muscles, crossing the Scalenus muscle at the upper part. 10. The Phrenic nerve on the left Scalenus anticus. 11. Small portions of the first part of the Subclavian artery on both sides with the Thyroid axis, and the commencement of the Inferior Thyroid, Trans- verse Cervical, and Supra-scapular branches. 12. On the left side, the Carotid sheath, and this being opened, the Internal Jugular vein, covering this part of the Common Carotid artery. The Vertebral vein is also seen. THE TRACHEA. 59 13. On the right side, the Common Carotid artery and Internal Jugular and Vertebral veins will be both exposed. 14. The Thoracic and right Lymphatic ducts, and lymphatic vessels and glands. 15. The right Vagus nerve, between the Carotid artery and Jugular vein, next crossing the Subclavian artery. 16. The right Ansa Vieusenii. 17. The first three ribs, and Costal cartilages. 18. The inner portions of the Subclavii muscles, between the first rib and the Clavicles, covered by the Costo- coracoid membranes. 19. The fascia of the External Intercostales. 20. The Internal Intercostales muscles showing through it. 21. The anterior ends of the External Intercostales. 22. The Anterior Sterno-clavicular and Inter-clavicular ligaments, and Anterior Costo-sternal ligaments. V. Saw through the Clavicles, divide the upper three ribs at the outer limit of the skin incisions, and saw through the Sternum at the lower level of the third cartilages. Remove the included piece of chest-wall, with the following struc- tures — a. The origins of the Sterno-hyoidei and Thyroidei muscles. b. The External and Internal Intercostal muscles. c. The Triangulares sterni muscles. d. The Internal Mammary arteries and veins. e. The Intercostal nerves, arteries, and veins of the upper two spaces. f. The Subclavii muscles will be divided at their inner portions. 60 A MANUAL OP DISSECTIONS. g. The parietal layers of the Pleum h. A few lymphatic glands between the Pleurse and Sternum. The Lungs will be found to be retracted on either side, and there will be now exposed — 1. Areolar tissue, fat, and lymphatics of the anterior Mediastinum, which should be cleared away. 2. The Trachea in the median line. 3. The right and left Internal Jugular veins, forming the right and left Innominates, and a small portion of the Superior Vena Cava, if distended. Entering the right and left Innominates are the Inferior Thyroid and Vertebral veins coming from above. The Supe- rior Intercostal veins from below, and the cut ends of the Internal Mammary branches. These veins should now be removed, and there will then be exposed — - 4. The arch of the Aorta giving off the Innominate branch on the right, which crosses over the Trachea, and bifurcates above into right Subclavian, and Common Carotid branches. The left Common Carotid and left Subclavian branches passing upwards and to the left. The Vertebral artery will be seen leaving the latter on the removal of its vein. 5. Crossing the arch of the Aorta are, from within out- wards — a. The left Phrenic nerve. 6. The Inferior Cardiac branch of the left Vagus. c. The Cardiac branch of the left superior Cervi- cal ganglion. d. The left Vagus giving off its Recurrent branch. e. The left Superior Intercostal vein. THE TRACHEA. 61 6. The left Pulmonary artery and the Ductus Arte- riosus. 7. The right Vagus nerve passing beneath the Innomi- nate artery. Its Recurrent branch is seen turning round the Subclavian artery, and its Inferior Car- diac branch lying on the outer side, and then pass- ing beneath the Innominate. 8. The left Vagus is seen above, between the Common Carotid and Subclavian arteries, and below passing beneath the left branch of the Pulmonary artery. 9. The right and left Ansae Vieusenii crossing the first parts of the Subclavian arteries. 10. Part of the superficial Cardiac plexus. 11. The right and left Phrenic nerves in front of the corresponding roots of the Lungs, and the Comes nervi'Phrenici arteries with them. 12. The anterior surface of the Pericardium, with some small arteries from the Internal Mammary, and small veins running to the left Superior Intercostal and Innominate veins. VI. Remove now — a. The isthmus and exposed parts of the lobes of the Thyroid gland. In doing this there will be taken away — 1. The Superior and Inferior Thyroid arteries. 2. The Middle and the remaining portions of the Inferior Thyroid veins. 3. Branches of nerves from the middle Cervical ganglion. b. Open the Pericardium. c. Divide the Aorta between Innominate and left Carotid branches^ turn the ends right and left, and fix them. 62 A MANUAL OE DISSECTIONS. There will now be exposed — The whole length of the Trachea from its origin to its "bifurcation. And the following additional structures — 1. Further portions of the Common Carotid arteries in the neck. 2. The (Esophagus more clearly at the root of the neck on the left side. 3. The whole of both Recurrent Laryngeal nerves. 4. A further portion of the Aortic arch. 5. The Pulmonary artery and its bifurcation. 6. The right Auricle and appendix, the tip of the left Auricular appendix, the Auriculo-ventricular groove, the upper part of the right Ventricle, and the com- mencement of the right and left Coronary arteries. 7. A further portion of the superficial Cardiac plexus of nerves. 8. The deep Cardiac plexus lying upon the bifurcation of the Trachea, with its radicles entering it from above. A Dissection to Expose the Vena Azygos Major. Position. — The body lying on its back. I. The Thorax 1 is opened, and the anterior part of its bony wall taken away, with the soft parts attached, by the following dissection— ■? a. Cut through the Manubrium just below the line of junction of the first Costal cartilages with it. 1 For an account of the structures divided, see the dissections of the Trachea and Internal Mammary arteries. .THE VENA AZTGOS MAJOR. 63 b. Divide through the junctions of the left Costal cartilages with the Sternum, from the second to the seventh inclusive. c. Cut through the ribs on the right side, in a line No. 9. leading from a point four inches from the middle line above to the tip of the tenth rib below. Open the Abdomen by a crucial incision, the trans- verse one of which should reach between the tips of the tenth ribs and the vertical to the left of the Xiphoid cartilage. 64 A MANUAL OP DISSECTIONS. e. Remove the piece of chest wall included between the above incisions, and the right upper flap of the Abdominal wall, cutting through the attach- ments of the Diaphragm to the inner surface of the ribs, the Round, and part of the Suspensory ligaments of the Liver. The other flaps are to be turned outwards. The following parts will be now exposed — A. In the Chest. 1. Bight Lung collapsed, and its root. 2. The Pericardium in the median line, covered by areolar tissue, fat, and lymphatics, and the remains of the Thymus gland. A 3. The process of deep Cervical fascia coming from above to the arch of the Aorta and the Pericardium. Remove the areolar tissue, fascia, and lymphatics, and expose — 4. The right and left Innominate veins, their junction, and the commencement of the Superior Vena Cava. The Inferior Thyroid, the Superior Intercostal, the right Internal Mammary branches are seen joining their corresponding Innominate trunks. 5. The arch of the Aorta, giving off the Innominate, left Carotid, and left Subclavian trunks. 6. The right Phrenic nerve in front of the root of the lung, and the left Phrenic crossing the Aortic arch. The Comes nervi Phrenici artery with each. 7. On the Pericardium small arteries from the Internal Mammary, and veins entering the left Innominate trunk. II. a. Dissect out the Vena Azygos major, as it arches up THE VENA AZYGOS MA JOE. 65 and over the root of the right Lung, and enters the Cava ; divide the root, and remove the viscus, taking away the ligamentum latum Pulmonis at the same time. The following structures will be cut through — 1. Bight Bronchus. 2. Bight Pulmonary artery. 3. Eight Pulmonary veins, t In this order from -fofui 'fr-b aagwormiB , and above downwards. A 4. Bight Bronchial artery and veins. At the back of the root. 5. Parts of the anterior and posterior Pulmonary plexuses of nerves. In front and behind respectively. 6. Lymphatics and glands. b. Hook the divided root well over to the left side, and with it the Heart, contained in the Peri- cardium. c. Remove the Pleura, as it is reflected from the posterior wall of the chest, over the bodies of the vertebrae, to the back of the root of the Lung. The (Esophagus will be found to be drawn to the left by the traction on the root of the Lung and Pericardium. There will now be exposed — 1. The Vena Azygos major, as it lies on the right side of the bodies of the vertebrae ; the right Intercostal veins, except those of the first two spaces, will be found joining it, the right Bronchial vein opens into it near its termination. The Vena Azygos minor inferior crosses the body of the seventh or 66 A MANUAL OF DISSECTIONS. eighth Dorsal vertebras to join it, and the Vena Azygos minor superior may be found joining the Azygoa major above,' when present. Both these structures pass beneath the Aorta. 2. The Thoracic Aorta is seen lying to the left side of the Azygos major and the Intercostal arteries, ex- cept those of the first and a part of the second spaces passing behind the vein. 3. The Thoracic duct in the interval between the Vein and the Aorta. 4. The (Esophagus to the left, with the Vagi nerves in front and behind. 5. The right gangliated Sympathetic cord lies externally on the heads of the ribs, giving from the second, third, and fourth ganglia (Quain), or third and fourth (Ellis) branches to the posterior Pulmonary plexus. The ganglia are also seen giving off the Splanchnic nerves which run down outside the Vena Azygos. The great Splanchnic arising by roots from the fifth or sixth to the ninth or tenth ganglia inclusive. The small from the tenth or eleventh, and the smallest from the twelfth. These are seen perforating the Diaphragm close to one another. Externally the ganglia are seen to send two branches to each Intercostal nerve. 6. The posterior wall of the chest will be seen formed by the ribs and Intercostal muscles. The internal muscles as far as the angles, and a thin fascia prolonged inwards to the vertebrae from them. On removal of this fascia, the Intercostal nerve, artery, and vein will be seen having the following relations to each other in the lower spaces, i.e. vein, artery, nerve from above downwards ; in the upper spaces the THE VENA AZYGOS MAJOH. 67 nerve is at first highest. The External Intercostal muscles are seen underneath the vessels and nerves extending as far inwards as the tubercles of the ribs. B. In the Abdomen. On opening the Abdomen as described above, the fol- lowing structures are exposed — 1. The Liver with the Round and Suspensory ligaments in the middle line, and the tip of the Gall bladder on the right. 2. The Stomach on the left. 3. The great Omentum. 4 The Caecum and ascending Colon, if distended. III. a. liaise the Liver, and dissect out in the small Omen- tum the Bile duct on the right, the Hepatic artery and its branches on the left, and the Portal vein behind. Divide these structures. b. Raise the great Omentum on to the ribs, and fix it there. Turn the small Intestine over to the left, and dissect out the Superior Mesenteric vessels as they pass over the third part of the Duo- denum. c. Ligature and divide the Hepatic flexure of the Colon, cut through the conjoined transverse Meso- colon and great Omentum from before backwards, dividing the middle Colic artery and vein ; turn the ends of the Colon right and left. d. Remove the Peritoneum between the Duodenum, and ascending Colon above, and the median line and ascending Colon below, and with it the Ileo and right Colic arteries, veins, and nerves, and 68 A MANUAL OF DISSECTIONS. take away the ascending layer of the transverse Meso-colon, in front of the Duodenum and Pan- creas. e. The Stomach is already pulled up, and fixed to the left ribs by the portion of great Omentum remaining. Divide now the Duodenum at its junction with the Pylorus, and again below on the right side of the Superior Mesenteric vein. Cut through the head of the Pancreas, and take it away with the piece of Duodenum included between the two incisions. The Pancreatico- duodenalis arteries, superior and inferior, will be divided and taken away, and the duct of the gland with the arteria Pancreatica magna cut through. The Bile duct will be removed, being already cut above. The Portal vein must be again divided just after the junction of the Splenic with the Superior Mesenteric, and taken away. There will now be exposed — 1. The Abdominal Aorta and the following branches, the Phrenics, the Coeliac axis, the Gastric, Splenic, the divided Hepatic and its Gastro-duodenal branch, the right, Supra-renal, Renal, Spermatic, and Lumbar branches. 2. The Inferior Vena Cava on its right side joined by the following veins, right Phrenic, Supra-renals, which however may enter the Renals (also seen), the right Spermatic, the Lumbar of both sides, and the Ascending Lumbar when present. 1 3. The right Crus of the Diaphragm on the right of the Aorta. 1 Vide Quain, vol. i. p. 473. THE VENA AZYGOS MAJOR. • 69 4. The right Psoas muscle, with the Genito-crural nerve, Spermatic artery, and Ureter lying upon it. 5. The Kidney, the upper end concealed by the Liver. 6. The Solar plexus and its prolongations along the ves- sels, viz.: — The Coeliac, Renal, Supra-renal, Phrenic plexuses. 7. The Splanchnic nerves perforating the right Cms of the Diaphragm. The endings of the small and lesser in the Coeliac and Renal plexuses respectively. The Semilunar ganglion and the ending of the greater, are hidden by the Inferior Cava on this side. IV.V". a. Cut through the Coronary and left Lateral ligaments of the Liver as far as the Inferior Cava. b. Divide the Diaphragm from before backwards, passing between the foramen Quadratum and opening for the (Esophagus down through the decussation of the Crura into the Aortic open- ing, cutting through the right Phrenic Artery ; now pull the halves of the Diaphragm to the right and left. c. Divide the Inferior Cava at its entrance into the right Auricle. d. Pull the Liver and with it the lower portion of the Inferior Cava well over to the right side, and fix it there. e. Divide the Supra-renal, Renal, and Spermatic arte- ries. /. Pull the upper part of the Aorta to the left. g. Remove the right Semilunar ganglion, which will be displayed by the removal of the Inferior Vena Cava, and the right side of the Solar plexus. 70 A MANUAL OF DISSECTIONS. There will now be exposed — 1. The whole length of the Vena Azygos Major. 2. The right Lumbar Sympathetic cord. 3. The Beceptaculum chyli and the Thoracic duct. A Dissection to Expose the Anterior and Posterior Circumflex Arteries. Position. — The body supported by blocks upon the opposite shoulder to that to be dissected. The arm is to be moved backwards and forwards, and rotated outwards and inwards according as the front or back is being dis- sected. In making the skin incisions the shoulder is to be drawn well down. I. Skin Incisions. 1. Along the outer third of the posterior border of the Clavicle, the inner border of the Acromion process, and the upper border of the Spine of the Scapula, for two-thirds of its extent. 2. A vertical incision from the centre of the inner border of the Acromion above, over the middle of the prominence of the shoulder to the inser- tion of the Deltoid muscle. 3. From the lower end of No. 2, obliquely upwards and forwards to the middle of the anterior fold of the Axilla, and upwards and backwards to the centre of the posterior fold. Reflect the flaps forwards and backwards and expose the superficial fascia, and — 1. The upper surface, of the outer third of the Clavicle, and of the Acromion process. THE CIRCUMFLEX ARTERIES. 71 The anastomosis on the Acromion between the Supra- scapular, Acromio-thoracic, and Posterior Circum- flex arteries. A cutaneous branch of the Posterior Circumflex artery at the lower part of the posterior border of the Del- toid muscle, sending a twig downwards to the skin over the long head of the Triceps muscle. Anterior View, No. 10. 4. A descending branch of the Acromio-thoracic artery between the Pectoralis major and the Deltoid muscles. 5. The Cephalic Vein also between these two muscles. Its branch of communication over the Clavicle with the External Jugular vein may be seen at its upper part. 6. Lymphatic vessels along the Cephalic vein. 72 A MANUAL OF DISSECTIONS. 7. Passing over the Acromion process, the Supra-acro- mial branches of the descending cutaneous nerves of the Cervical plexus. 8. The lower branch of the Circumflex nerve passing round the posterior border of the Deltoid below the middle, and supplying the skin over the lower two- thirds of the muscle, and further giving off a twig to the skin over the long head of the Triceps muscle. Offsets of the upper branch of the nerve pass be- tween the muscnlar fibres, and also turn down over the lower part of the muscle. 9. The bursa over the Acromion process. II. Remove these structures, and the fascia lata, and expose — 1. The Deltoid muscle forming the prominence of the shoulder. 2. In front of this the outer part and insertion of the Fectoralis major muscle. 3. Below the Pectoralis major muscle the Biceps muscle is seen at its upper part. The part exposed is mainly the short head, but a small portion of the long head comes into view. 4. Behind the Deltoid muscle the Latissimus dorsi and Teres major and minor muscles are seen in part, and the Inspinatus muscle above them covered by its fascia. 5. The upper part of the external head of the Triceps muscle is exposed behind the Deltoid muscle at its lower part, running up beneath it. 6. A small twig of the DorsaUs Scapulae artery is seen posteriorly between the Teres muscles. III. Detach the Deltoid muscle from its origin and reflect it downwards. The branches of the Posterior Circumflex THE CIRCUMFLEX ARTERIES. 73 artery and the accompanying nerve to its substance and on its cutaneous surface may be preserved. There will now be seen — 1. A further portion of the Acromion, and the Coracoid process of the Scapula. The head, and greater and lesser Tuberosities of the Humerus. 2. The Coraco-acromial ligament, and the Coraco-humeral portion of the Capsule. 3. The insertions of the Supra-spinatus, Infra-spinatus, and Teres minor muscles from above downwards into the great Tuberosity. 4. A small portion of the insertion of the Subscapularis muscle into the lesser Tuberosity, especially seen in the adducted position of the arm. 5. The origin of the Coraco-brachialis and short head of the Biceps muscles from the Coracoid process, and the tendon of the long head of the latter perforating the Capsular ligament. 6. A further part of the tendon of the Fectoralis major muscle passing in front of the Coraco-brachialis and short head of the Biceps muscles, and inserted into the outer Bicipital ridge. 7. A further portion of the Teres major muscle is Been behind, covering in this position the Latissimus dorsi muscle. 8. The long head of the Triceps muscle is seen posteriorly passing between the Teres major and minor muscles, the former being in front of it. The Teres major and minor muscles diverge from one another as they pass to the Humerus so as to form a triangle, of which the bone forms the base, the Teres minor muscle the upper and internal, and the Teres major muscle the lower and external boundaries. The 74 A MANUAL OF DISSECTIONS. long head of the Triceps muscle passing to the Scapula divides this triangle into two parts, an upper or external part quadrilateral in shape, and a lower or internal triangular. 9. The Posterior Circumflex artery and vein, passing through the quadrilateral space. 10. The Anterior Circumflex artery with its vein, passing beneath the Ooraco-brachialis and Biceps muscles, winding round the neck of the Humerus and anastomosing with the posterior artery. 11. The Circumflex nerve accompanying the Posterior Circumflex artery. 12. The bursa between the Subscapularis muscle and the Acromion. IV. a. Cut through the Pectoralis major in front at the point of its appearance from beneath the reflected skin, and turn it outwards. b. Divide the Coraco-brachialis and short head of the Biceps muscles, and turn them downwards. The Musculo-cutaneous nerve will be carried with the former muscle. c. Divide the long tendon of the Biceps muscle, and with it the aponeurotic process from the tendon of the Pectoralis major muscle to the great Tuberosity. Open up the sheath of the tendon. d. Remove the fascia and fat and glands from the upper part of the Axillary space, dissecting out the various structures met with. There will now be exposed — 1. The Pectoralis minor muscle in front, attached to the Coracoid process. 2. The Subscapularis muscle more fully. It is seen to THE CIRCUMFLEX ARTERIES. 75 hide the Teres minor muscle when looked at from the front, and to take the place of this muscle in the boundaries of the quadrilateral and triangular spaces on the anterior aspect. 3. The insertions of the Latissimus dorsi and Teres major muscles, the former attached to the floor and the latter to the inner ridge of the Bicipital groove. 4>. The upper part of the internal head of the Triceps muscle below the Teres major muscle. 5. The third portion of the Axillary artery, and its branches — viz., the Subscapular, which is seen run- ning downwards on the Subscapular muscle, giving the Dorsalis Scapulae branch through the triangular space. The Anterior Circumflex is hidden by the Median nerve at its origin, and also by the Musculo- cutaneous nerve, but this has been pulled down with the Coraco-braohialis muscle ; the artery is seen in all the rest of its course, and a branch running up the Bicipital groove to the joint, may be traced. The Posterior Circumflex branch is hidden at its origin by the nerves on the inner side of the artery to be mentioned immediately, and by the Axillary vein, but it may be seen passing backwards through the quadrilateral space. The Long Thoracic branch of the second portion of the Axillary trunk may be seen descending along the outer border of the Peo- toralis minor muscle. An External Mammary branch may be seen sometimes crossing the centre of the space, arising from the third part of the main trunk. 6. The Axillary vein is seen internal to the artery, receiving radicles corresponding to the above- named branches of the latter. 76 A MANUAL OF DISSECTIONS. 7. The Median and Musculo-cutaneous nerves are outside the artery, the latter gives branches to the Coraco- brachialis muscle before piercing it. 8. The Internal Cutaneous nerve is superficial to it. 9. The Ulnar, inner head of Median, and lesser Internal Cutaneous nerves are internal to the artery. 10. The Intercosto-humeral nerve passes out from the second intercostal space lower down, and communi- cates by a cross branch with the lesser Internal Cutaneous nerve. 11. The Musculo-spiral nerve is behind the artery. The origin of its Internal Cutaneous branch is seen. 12. The Circumflex nerve is also behind the artery, ac- companying the Posterior Circumflex artery. 13. The Subscapular nerves to the Teres major and Latis- simus dorsi muscles may be seen passing down to their respective muscles. V. a. Divide the Axillary vein, and turn the ends inwards and outwards. b. Hook upwards the Median nerve. This exposes the origin of the Anterior Circumflex artery. c. Hook downwards the Ulnar, both Internal Cuta- neous and the Musculo-spiral nerves. The origin of the Posterior Circumflex artery will now be un- covered. Both the Circumflex arteries may now be seen in their entire distribution. THE MUSCULO-SPIRAL NERVE. 77 A Dissection to Expose the Musculo-spiral Nerve. Position. — The body lying upon its face, the arm extended at right angles to the trunk, and rotated in- wards. I. Skin Incisions. 1. From the tip of the Acromion process down the outer border of the arm for about half its extent, and then forwards to the centre of the bend of the elbow half an inch below the external Condyle. Posterior new. i Anterior view. No. 11. From the upper end of No. 1 downwards and backwards to the centre of the Axillary border of the Scapula. From the lower end of No. 1, transversely out- wards below the external Condyle to the Ole- cranon process. 78 A MANUAL OF DISSECTIONS. Reflect the flap inwards and expose the superficial fascia and the following cutaneous structures — 1. Branches of the Posterior Circumflex artery, turning round the posterior border of the Deltoid muscle below the middle, and supplying the skin over it. An offset is also given to the integument over the Triceps muscle. 2. Twigs of the Superior Profunda artery in front of and behind the external Condyle. 3. In front of the elbow, the Median-cephalic vein joined below by the Radial ; the Cephalic vein is also seen in the lower half of the arm. 4. The Supra-acromial branches of the Cervical plexus over the upper part of the Deltoid muscle.- 5. Branches of the Circumflex nerve turning round the posterior border of the Deltoid at the lower part, and having a similar distribution to the Posterior Circumflex artery. Other branches of the nerve perforate the muscle. 6. The Intercosto-humeral nerve supplying the skin of the upper half of the inner aspect of the arm ; a few filaments passing over the posterior Axillary fold. 7. The posterior branch of the third Lateral Cutaneous nerve often reaches the upper part of the arm. 8. The Internal Cutaneous branch of the Musculo-spiral nerve passing back beneath the Intercosto-humeral and supplying the skin nearly as far as the Ole- cranon. 9. The superior External Cutaneous branch, of the Mus- culo-spiral nerve lies with the Cephalic vein. The inferior External Cutaneous branch over the pos- terior aspect of the arm. THE MUSCULO-SPIRAL NERVE. 79 10. In front of the elbow beneath the Median-cephalic vein, the Musculo-cutaneous nerve. 11. The upper part of the Olecranon bursa. II. Remove the preceding and expose the fascia lata. Above the elbow it will be found to form the ex- ternal intermuscular septum. Clear it away except this process. The following structures will be displayed — 1. The posterior portion of the Deltoid muscle. 2. The Latissimus dorsi muscle passing beneath it at the lower part, but separated by the long head of the Triceps muscle. 3. The Teres major muscle, taking a similar course to the Latissimus, but above it. 4. A small portion of the lower border of the Teres minor above the major muscle. It may, however, not come into view. 5. The long head of the Triceps muscle below the pos- terior border of the Deltoid and superficial to the Latissimus dorsi, and Teres major muscles. The outer head of the Triceps lower down the arm, and above the long head in the abducted position. Still lower, the outer portion of the inner head and the tendon. 6. In front of the elbow the outer border of the Biceps muscle, and beneath it the 7. Brachialis anticus muscle. 8. Descending from the external Condyloid ridge the Supinator longus, and Extensor carpi radialis longior muscles. 9. Still lower down the upper part of the Anconeus muscle, behind and below the external Condyle. 10. Between the Brachialis anticus and Supinator longus 80 A MANUAL OF DISSECTIONS. muscles a further portion of the External Cutaneous nerve will be seen. 11. On pulling outwards the Supinator longus and Ex- tensor carpi radialis longior muscles, the Musculo- spiral nerve may be seen perforating the external intermuscular septum, running down beneath them, and dividing at the level of the external Condyle into Radial and Posterior Interosseous branches. The offsets to these muscles and the Brachialis anticus may also be traced. 12. Running down with the Musculo-spiral nerve the anterior branch of the Superior Profunda artery will be seen inosculating below with the Radial Recur- rent branch. III. a. Hook the posterior border of the Deltoid muscle well forwards. b. Cut through the long, and outer heads of the Triceps muscle. c. Divide the Latissimus dorsi and Teres major muscles. d. Divide the Supinator longus and Extensor carpi radialis longior muscles. There will now be exposed — 1. The head of the Humerus and the upper part of the shaft. 2. The Subscapularis muscle along the Axillary border of the Scapula. 3. The Teres minor muscle parallel with and behind the preceding. 4. Lower down at the elbow the Supinator ferevis muscle. 5. Most of the second, and all the third part of the Axillary artery, and the commencement of the Bra- THE MITSCULO-SPIKAL NERVE. 81 chial, in front of the Subscapulars and along the inner border of the arm. 6. The Subscapular branch, running down the Axil- lary border of the Scapula, crossing behind the Musculo-spiral nerve, and giving off its Dorsalis Scapulae branch below the Teres minor muscle, this branch then passes beneath the muscle. 7. The Posterior Circumflex artery is seen at its origin and in the rest of its course. 8. The origin and upper part of the Superior Profunda branch of the Brachial artery. 9. The Axillary vein, internal to and in front of its artery, the venae comites of the Brachial artery, and veins corresponding to all the arterial branches above enumerated. 10. The Circumflex nerve is seen with the Posterior Cir- cumflex artery. 11. The Musculo-spiral nerve above and below, and the origin of its Internal Cutaneous branch at its upper part. 12. Deep down in the dissection above, the Musculo- cutaneous nerve may be seen entering the Ooraco- brachialis muscle and also the Ulnar nerve, but it is not necessary to find them, for the nerve in course of dissection is superficial to them in this position. IVIV. a. Remove a portion of the lower border of the Sub- scapulars muscle near the Humerus. Then the bifurcation of the posterior cord of the Brachial plexus into the Circumflex and Musculo-spiral nerves can be seen. This division takes place internal to the Axillary border of the Scapula, and if necessary a portion of the bone may be G 82 A MANUAL 01" DISSECTIONS. chipped away ; nevertheless this is not absolutely requisite. b. Divide the Subscapular vessels. c. Trace the Musculo-spiral nerve through the sub- stance of that portion of the Triceps not yet divided, along the Musculo-spiral groove. In this situation the Superior Profunda artery will be found lying upon it, and must be removed. The upper part of the external intermuscular septum must also be taken away. The nerve and its offsets may now be completely traced to its bifurcation. The Internal branches, viz., to the inner and middle heads of the Triceps, the Ulnar Collateral, and the Internal Cutaneous. The Posterior branches, viz., to the outer head, and the Anconeus muscle ; the latter a long slender offset passing through the substance of the muscle with a branch of the Superior Profunda artery. The Ex- ternal branches, viz., the two External Cutaneous, and to the Supinator longus and Extensor carpi radialis longior, may all be followed out; some of them, however, have •been previously dissected. A branch to the Brachialis an- ticus muscle from the outer set may be sometimes traced. A Dissection oe the Anastomoses about the Elbow-joint. Position. — It will be necessary to move the arm about, and it should at first lie on its posterior, and next on its anterior surface. I. Skin Incisions. 1. A circular one around the arm two inches above the Condyles of the Humerus. ANASTOMOSES OF ELBOW. 83 2. A circular one around the forearm, two inches below the same points. 3. A longitudinal one along the median line in front, between the two circular incisions. Reflect and remove the included portion of skin, and expose the superficial fascia containing — In Front — 1. The Cutaneous veins. The Radial, on the outer side. The Anterior and Posterior Ulnar, the latter coming from the posterior surface of the forearm, and the two uniting into one trunk. The Median, along the centre of the forearm, dividing into two branches, Median-cephalic externally and Median-basilic inter- nally, and receiving at its bifurcation a deep vein from the venas comites of the Brachial artery. The Radial vein joins the Median-cephalic, and the two form the Cephalic vein which runs up on the outer side of the arm. The united trunk of the Ulnar veins joins the Median-basilic, and the result is the Basilic vein passing upwards on the inner side of the arm. 2. With the Cephalic vein is the superior External Cuta- neous branch of the Musculo-spiral nerve. 3. Behind the Median-cephalic vein the External Cuta- neous nerve running down to the forearm. 4. The Internal Cutaneous nerve at the inner side of the arm dividing into numerous branches. One of these passes to the back of the forearm over the internal Condyle ; the others pass some superficial to, and some beneath the Median-basilic vein, to the front of the forearm. 5. Cutaneous branches of the Radial Recurrent artery are found in front of the outer Condyle. 84 A MANUAL OF DISSECTIONS. 6. Lymphatics, and a gland in front of the elbow, and one above the inner Condyle. Behind will be found — 7. The Olecranon process covered by a bursa. 8. The nerve of Wrisberg between the internal Condyle and Olecranon, sending filaments inwards over the lower part of the arm, the inner Condyle, and the Olecranon. A communication may be traced with the Internal Cutaneous nerve. 9. The inferior External Cutaneous branch of the Mus- culo-spiral nerve giving twigs over the posterior surface of the arm and forearm. 10. Cutaneous twigs of the following arteries are seen : of the Interosseous Recurrent behind the outer Con- dyle ; of the Posterior Ulnar Recurrent and Inferior Profunda behind the inner Condyle. II. Remove and expose the fascia lata which dips down to the external and internal Condyloid ridges to form the corresponding intermuscular septa, and is joined in front by the semilunar process of fascia derived from the tendon of the Biceps muscle. III. Remove the preceding except the septa, and there will be now exposed — In Feont — 1. The Supinator longus and Extensor carpi radialis longior muscles running down from the external Condyloid ridge. 2. The Brachialis anticus muscle and the lower part of the fleshy belly and tendon of the Biceps muscle in the centre, superficial to the preceding. These pass from the arm, the former to the Coronoid process of the Ulna, the latter to the Tuberosity of the Radius. ANASTOMOSES OF ELBOW. 85 3. The origin of the Pronator radii teres muscle from the internal Condyloid ridge, and the common tendon of the Pronator radii teres, Palmaris longus, Flexor sublimis digitorum, and Flexor carpi ulnaris muscles from the internal Condyle. 4. A small piece of the Supinator brevis muscle in the floor of the triangular space. Behind — 5. The tendon of the Triceps muscle inserted into the Olecranon process. 6. The Anconeus muscle passing from the outer Condyle to the outer surface of the Olecranon process. 7. The common tendon of the following muscles from the external Condyle : Extensor carpi radialis brevior, Extensor communis digitorum, Extensor minimi digiti, Extensor carpi ulnaris. The origin of the Supinator brevis muscle from the same bony point. 8. The origin of the Flexor carpi ulnaris muscle from the inner surface of the Olecranon process, and the pos- terior margin of the Ulna. 9. The external and internal intermuscular septa. In Front — 10. A further portion of the External Cutaneous nerve, emerging on the outer side between the Biceps and Brachialis anticus muscles. 11. The Musculo-spiral nerve lying deeply between the • Supinator longus and Brachialis anticus muscles, and dividing on a level with the external Condyle into Radial and Posterior Interosseous branches. Offsets from the trunk are traceable to the Supinator longus and Extensor carpi radialis longior muscles, and occasionally one supplying the Brachialis an- 86 A MANUAL OF DISSECTIONS. ticns muscle. With the nerve a branch of the Supe- rior Profunda artery is seen. 12. The Brachial artery with its venae comites is seen in- ternal to the Biceps tendon dividing opposite the head of the Radius into Radial and Ulnar branches. The Anastomotica Magna branch is found above the elbow, sending a small branch down beneath the Pronator radii teres muscle, and perforating the internal intermuscular septum. 13. The Median nerve lies internal to the Brachial artery, and gives off a branch above the elbow to the Pro- nator radii teres muscle. Behind — 14. The Anastomotica Magna and Inferior Profunda arte- ries are found in the space between the internal Condyle and Olecranon process. 15. The Ulnar nerve with the preceding. IY. Divide now — a. The origin of the Pronator radii teres muscle from the internal Condyloid ridge, and its inner ten- dinous head (which overlaps the Anterior Ulnar Recurrent artery) from the inner surface of the Coronoid process. b. The common Flexor tendon from the internal Con- dyle. c. The outer head of the Flexor carpi ulnaris muscle from the Olecranon process and posterior border of the Ulna. Turn all the preceding muscles downwards. d. Detach the Supinator longus, and Extensor carpi radialis longior muscles from the external Condy- loid ridge and pull them down. e. Remove the Anconeus muscle. ANASTOMOSES OF ELBOW. 87 f. Take away the Triceps muscle. Do this piecemeal, dissecting out in its substance the Superior Pro- funda artery. A branch will be found running to the back of the external Condyle between the muscle and the bone, and an arch across the back of the bone immediately above the Olecra- non fossa to the inner side, joining with the Anastomotica Magna artery. There will now be exposed — In Front of the outer Condyle — The Radial Recurrent artery, joining with the anterior branch of the Superior Profunda. Behind the outer Condyle — The Interosseous Recurrent artery anastomosing with the posterior branch of the Superior Profunda, and a branch from the Anastomotica Magna coming from the inner side. It sends a branch over the Ole- cranon to join the Posterior Ulnar Recurrent artery. In Front of the internal Condyle — A slender branch from the Anastomotica Magna artery, uniting with the Anterior Recurrent branch of the Ulnar artery. Behind the internal Condyle — The general anastomosis of the Superior and Inferior Profunda and Anastomotica branches of the Brachial artery with one another, and with the Posterior Recurrent branch of the Ulnar artery running up from the forearm. 88 A MANUAL OF DISSECTIONS. A Dissection to Expose the Supinator Brevis Muscle. Position. — During the dissection the forearm should be pronated and supinated as occasion arises. The muscle will be best displayed with the forearm strongly pronated and resting upon its inner border. I. Skin Incisions. 1. Transversely from the upper border of the Olecra- non process of the Ulna outwards over the exter- nal Condyle of the Humerus to the centre of the bend of the elbow in front. 2. Transversely from the posterior border of the Ulna at its centre round the outer border of the fore- arm to the median line in front. 3. Join the anterior extremities of the preceding by a longitudinal incision along the median line. Reflect .the flap backwards and outwards, and expose the superficial fascia containing — 1. The Median vein, its deep communicating branch with the venae comites of the Brachial artery at its point of bifurcation, and the lower part of the Median- cephalic branch. The Radial vein joining the latter. 2. Cutaneous offsets of the Radial and Interosseous Re- current arteries in front of and behind the external Condyle respectively. A transverse branch of the latter is found behind the Olecranon, and cutaneous twigs of the Superior Profunda artery behind the external Condyle. 3. A few of the lowest twigs of the superior External THE SUPINATOR BREVIS. 89 Cutaneous branch of the Musculo-spiral nerve in front of the elbow, and the inferior External Cutaneous branch of the same nerve behind the elbow and the forearm. 4. The External Cutaneous nerve beneath the Median- Cephalic vein running down the front of the fore- arm, giving off its posterior branch at the lower part of the dissection. 5. Part of the Olecranon process, and the external Con- dyle. The former covered by its bursa. II. Remove trie preceding cutaneous structures and ex- pose the fascia lata. Clean this away, and the fol- lowing structures will be displayed, commencing from the front and passing backwards — 1. The outer part of the insertion of the Brachialis anti- cus muscle. 2. The tendon of the Biceps muscle running down to the Tuberosity of the Radius. 3. The lower part of the Pronator radii teres muscle in its whole width below, but only its outer border above. 4. The Supinator longus muscle descending from the arm, on the outer side of the forearm. This should be hooked outwards. 5. A small portion of the Supinator brevis muscle deep down between the two immediately preceding muscles. 6. The Extensor carpi radialis lpngior muscle outside the Supinator longus muscle. 7. The common tendon and upper fleshy portions, of the following muscles in their order from without inwards — viz., Extensor carpi radialis brevior, Ex- tensor communis digitorum, Extensor minimi di- 90 A MANUAL OF DISSECTIONS. giti, Extensor carpi ulnaris, and a portion of the origin of the latter from the posterior border of the Ulna. 8. The Anconeus muscle running from the outer Condyle to the outer side of the Olecranon. 9. In front, internal to the Biceps tendon, the lower part of the Brachial artery and its division into Radial and Ulnar branches. The Radial Recurrent branch passing up beneath the Supinator longus muscle. These arteries are accompanied by their veins. 10. The anterior terminal branch of the Superior Pro- funda artery above, beneath the Supinator longus muscle, anastomosing with the Radial Recurrent. 11. The Median nerve internal to the Brachial artery, and its branch to the Pronator radii teres muscle. 12. Beneath the Supinator longus muscle, but seen by pulling it outwards, the Musculo-spiral nerve divid- ing opposite the external Condyle into Radial and Posterior Interosseous branches. III. Divide now — a. The Supinator longus and Extensor carpi radialis longior muscles, and throw the ends upwards and downwards. b. The common Extensor tendon, and pull the fleshy bellies of the muscles taking origin from it down- wards. Their nerves from the Posterior Inter- osseous will be cut. c. The Pronator teres muscle, and hook the ends up- wards and downwards. The upper portion will carry with it the Median nerve. There will now be exposed — 1. The upper and outer portion of the Flexor profundus digitorum muscle. ivy. THE SUPINATOR BREVIS. 91 2. The Radial artery, its Recurrent branch, and the anterior branch of the Superior Profunda artery more fully. 3. Posteriorly, the upper part of the Posterior Inter- osseous artery at its point of emergence below the Supinator brevis muscle. The Recurrent branch will be seen passing up upon this muscle and beneath the Anconeus. Sometimes this offset pierces the Supinator brevis. 4. The Posterior Interosseous nerve, emerging from the Supinator brevis is seen, giving branches to the Ex- tensor muscles, which however are divided now, and should have been traced when these muscles were reflected. Remove now the Radial vessels and nerve, the Inter- osseous Recurrent artery, and the Posterior Inter- osseous nerve. Pull inwards, or remove some of the outer fibres of the Anconeus muscle which slightly overlap the Supinator brevis muscle. Take away that portion of the Flexor profundus digitorum muscle which runs up to the Coronoid process externally to the Brachialis anticus in- sertion. The Supinator brevis muscle will now be fully exposed. 92 A MANUAL OB DISSECTIONS. A Dissection to Expose the Flexor Longus Pollicis Manus Muscles. Position. — The forearm supinated, the wrist and thumb extended. I. Skin Incisions. 1. Longitudinally along the median line, commenc- ing above at the centre of the forearm opposite to the head of the Radius, and ending below at the middle of the palm of the hand on a level with the upper border of the abducted thumb. No. 12. 1 2. Transversely above from the upper end of No". 1 to the outer border of the forearm. 3. Transversely from the lower end of No. 1, along the inner border of the thumb to the tip. 1 The dotted line is carried a little too far upwards. THE FLEXOR LONGUS POLLICIS. 93 Reflect the flap outwards, and expose the superficial fascia containing — 1. Branches of the Princeps Pollicis artery on either side of the thnmb. 2. The Radial vein along the outer border of the forearm. 3. The Median vein along the centre, with the deep com- municating branch above. 4. The anterior branch of the External Cutaneous nerve along the outer border of the forearm. 5. Twigs from the anterior branch of the Internal cuta- neous nerve. 6. The Cutaneous Palmar branch of the Median nerve in the middle line just above the Annular ligament and passing over it into the palm. 7. Digital branches of the Median nerve to eitfier side of the thumb. II. Remove the preceding structures, and expose the fascia lata. At the wrist this is seen to be strengthened by transverse fibres, and to constitute in that situation the Anterior Annular ligament, 1 being attached internally to the Unciform and Pisiform bones, and externally to the Sca- phoid and Os Trapezium. On the palm of the hand is seen the posterior part of the Palmar fascia, thick in the centre, but thin over the Thenar eminence. III. Remove now the" fascia lata, except that part forming the Anterior Annular ligament. Detach the lateral part of the Palmar fascia from the ball of the thumb. There will now be exposed — 1. The Extensor carpi radialis longior muscle most ex- ternally. 2. Internal to the preceding the Supinator longus muscle. 1 Only the outer part is uncovered. 94 A MANUAL OF DISSECTIONS. 3. Next the Pronator radii teres muscle. 4. Then the Flexor carpi radialis muscle. 5. Still more internally the Palmaris longus, its tendon passing over the Annnlar ligament, to be inserted into the Palmar fascia. 6. The outermost tendon of the Flexor sublimis digitorum will probably be seen at the lower part. 7. Forming the ball of the thumb are the following muscles: the Abductor pollicis, most superficial, running from the lower border of the Annular liga- ment to the outer side of the base of the proximal Phalanx. The Opponens muscle is beneath it, but a small portion is seen at its outer border. The outer head of the Flexor brevis pollicis is seen inserted, with the Abductor muscle, into the outer side of the base of the proximal Phalanx. The insertion of the Adductor and inner head of the Flexor brevis pollicis muscles is seen at the inner side of the base of the proximal Phalanx. 8. Some of the fleshy fibres of the Flexor longus pollicis muscle are seen between the tendons of the Supi- nator longus and Flexor carpi radialis muscles, and its tendon emerging from between the two heads of the Flexor brevis pollicis to its insertion into the ungual Phalanx of the thumb. 9. A small piece of the Pronator quadratus muscle in- ternal to the Supinator longus tendon, on the lower two inches of the Radius. 10. The Radial artery is seen to be overlapped above by the Supinator longus, and to be superficial below between the tendon of that muscle and that of the Flexor carpi radialis longior. It is found to give off mus- cular offsets, and the Superficial Volar branch, over THE FLEXOR LONGUS POLLICIS. 95 or between the muscles of the Thenar eminence, and to be accompanied by two venae comites. 11. The Radial nerve is seen to lie on the onter side of the artery as far as about three inches above the wrist. 12. A small piece of the Median nerve is seen just above the wrist, between the Flexor carpi radialis and outermost Flexor sublimis tendons. inv. a. Remove the outer part of the Anterior Annular ligament, and take away the central thick por- tion of the Palmar fascia as far as it is exposed, having previously divided the insertion of the Falmaris longus muscle into it. b. Remove the exposed portion of the Pronator radii teres muscle. c. Cut through the Flexor carpi radialis above and below, and remove it. Its nerve from the Median will be divided. d. Cut the Palmaris longus above and remove it. There will now be exposed — 1. The outer portion of the Flexor sublimis digitorum muscle, its origin from the oblique line and upper three fourths of the anterior border of the Radius ; its four tendons passing over the Carpal bones in pairs (the tendons of the middle and ring fingers being in front), and spreading out in the palm to the fingers. The two innermost are not seen. 2. A further portion of the Flexor longus pollicis muscle above the wrist. 3. The Pronator quadratus muscle more fully. 4. In the palm, the tendons of the Flexor profundus muscle 2 beneath those of the Flexor sublimis, and 1 The two outermost only are seen. 96 A MANUAL OF DISSECTIONS. the two outer Lumbricales muscles arising from the outer side of those going to the index and middle fingers. These tendons, as well as those of the superficial Flexor muscle, are surrounded by syno- vial membrane. 5. The outer portion of the Superficial Palmar arch is seen, and just the commencement of the branch to the contiguous sides of the index and middle fingers. 6. The Median nerve is seen in the palm, somewhat en- larged and divided into two parts. The outer division supplies branches to the Abductor, Oppo- nens, and outer head of Flexor brevis pollicis muscles, and two Digital branches to the outer and inner borders of the thumb, and a single branch to the outer side of the index. This last branch is only seen at its origin. The commencement of the branch of the inner division, which divides for the contiguous sides of the index and middle fingers, also comes into view. The twigs to the exposed Lumbricales muscles from the two last-mentioned branches may be traced. The nerves here lie be- neath the artery. V. a. Divide now the outer division of the Median nerve, and the Superficial Palmar arch. b. Clean away the synovial membrane from the Flexor tendons. c. Divide the Flexor sublimis muscle longitudinally along its whole length. Cut through the index and middle tendons, and reflect the Radial origin of the muscle outwards. The Flexor longus pollicis muscle will now be fully ex- THE ADDUCTOR POLLICIS. 97 posed by opening up the Palmar sheath of its tendon ; and the occasional slip from the inner part of the Coronoid process of the Ulna may be traced. In addition there will be seen — 1. The outer part of the Flexor profundus digitorum muscle in the forearm. 2. The Median nerve in the forearm with its branches to the Flexor sublimis muscle. A Dissection oe the Anterior Surface oe the Adductor Pollicis Manus Muscle. Position. — The hand lying upon its dorsal surface, the thumb strongly abducted and rotated outwards. I. Skin Incisions. 1. From the inner border of the base of the proximal Phalanx of the thumb to the inner border of the root of the middle finger. 2. Along the median line from the inner end of the preceding to a point half an inch in front of the wrist. Keflect the flap backwards and expose the superficial fascia containing granular fat, and — 98 A MANUAL OF DISSECTIONS. 1. Cutaneous branches of artery from the Superficial Palmar arch. 2. Branches of the Musculocutaneous nerve over the ball of the thumb. 3. The Cutaneous Palmar branch of the Median nerve at the centre of the wrist. II. Remove and expose the central thick, and the outer thin portions of the Palmar fascia, and the digitations of the former to the second and third fingers. III. Remove the preceding and expose — 1. The inner tendon of insertion of the Flexor brevis pollicis muscle, and conjoined with it on its inner side the insertion of the Adductor pollicis muscle. 2. The tendon of the Flexor longus pollicis muscle will be seen on the outer side of the preceding, owing to the retraction of the skin. 3. A small piece of the Abductor indicis muscle in front of the Adductor pollicis muscle on the outer side of the index finger. 4. The tendons of the superficial and beneath them of the deep Flexor muscles of the fingers to the second and third digits. They are seen passing into their special sheaths, which extend half an inch into the palm. The Lumbricales muscles of the index and middle fingers are seen, and on the removal of the superficial Mexor tendons are found to arise each from two tendons of the deep. 5. The Princeps Pollicis artery is seen on the thumb, and also its bifurcation. 6. The Radialis Indicis artery on the outer side of the index finger. 7. The outer portion of the Superficial Palmar arch, THE ADDUCTOR POLLICIS. 99 formed by the Superficial part of the Ulnar artery, joining with the Snperficialis VoIbb branch of the Radial, and a very constant communication with the Radialis Indicia artery. A branch of the arch is seen bifurcating for the contiguous sides of the index and middle fingers. 8. Single branches of the Median nerve to the inner side of the thumb and the outer side of the index finger ; and one which bifurcates for the contiguous sides of the index and middle digits. The two inner of these branches are found to supply the two outer Lumbrical muscles. The arteries in the palm are superficial to the nerves. IV. Remove — a. The Superficial Palmar arch and its branches. b. The branches of the Median nerve to the index and middle fingers. c. Divide the Flexor tendons of the fingers and pull them forwards. There will now be exposed — 1. The Adductor pollicis muscle arising from the anterior two thirds of the Metacarpal bone of the middle finger, and inserted into the inner side of the base of the proximal Phalanx of the thumb. 2. In front of this, the Abductor indicia muscle on the outer side of the index finger, and the lower part of the Palmar and Dorsal Interossei muscles of the second space ; a'rching over their lower parts the piece of the Transverse Metacarpal ligament between the heads of the second and third Metacarpal bones. 3. The inner fleshy head of the Flexor brevis pollicis, and its tendinous insertion (often containing a sesa- 100 A MANUAL OF DISSECTIONS. moid bone), conjoined with the insertion of the Adductor pollicis muscle. 4. A very small piece of the outer part of the Deep Palmar arch between the Flexor brevis and Adduc- tor pollicis muscles at their inner parts. 5. The Deep branch of the Ulnar nerve supplying the inner head of the Flexor brevis and Adductor pol- licis muscles. A Dissection to Expose the deep Palmae Arch and its Branches. Position. — The hand lying upon its dorsal aspect with the thumb strongly abducted, and the fingers extended. I. Skin Incisions. 1. Along the median line of the palm from the line marking the junction of the wrist with the fore- arm, to the centre of the root of the middle finger. 2. Transverse incisions from the upper end of No. 1, to the inner and outer borders of the forearm respectively. 3. Transverse incisions from the lower end of No. 1, along the roots of the fingers to the inner and outer borders of the hand. Reflect the flaps inwards and outwards, and expose the superficial fascia, containing granular fat, and — 1. The Superficial Transverse ligament across the roots of the fingers. 2. The Palmaris brevis muscle, along the inner border of the hand. THE DEEP PALMAR ARCH. 101 3. The filaments of the Musculo-cutaneous nerve over the ball of the thamb. 4. The Cutaneous Palmar branch of the Median nerve, passing down over the centre of the Annular liga- ment and along the centre of the palm, and com- municating with 5. The Cutaneous Palmar branch of the Ulnar nerve, which lies over the Ulnar artery and supplies the skin of the inner border of the hand. 6. Unnamed twigs of the Median and Ulnar nerves to the skin of the palm, and small branches of artery from the Superficial Palmar arch. II. Remove the superficial fascia, the cutaneous nerves, and the Palmaris brevis muscle. The branch of nerve to the muscle from the Ulnar will be divided. There will now be exposed — 1. The Anterior Annular ligament across the wrist. 2. The Palmar fascia. This will be seen to be made up of three divisions, a central thick triangular portion, and two lateral parts covering the Thenar and Hypothenar eminences. The central portion has its apex at the Annnlar ligament,, and its base is cut into four processes, one for each of the fingers. These are connected together by the Superficial Transverse ligament which crosses them at the roots of the fingers. 3. The commencements of the sheaths of the Flexor tendons are seen, and these are found to be joined by the Digital processes of the Palmar fascia. 4. The tendon of the Palmaris longus muscle is seen passing over the Annular ligament to join the apex of the central triangular division of the Palmar fascia. 102 A MANUAL OF DISSECTIONS. 5. In the intervals of the four Digital processes of the Palmar fascia, the following structures are seen : — a. Small portions of the Lumbricales muscles in each space. b. The Digital vessels, and nerves. Those supplying the outer side of the index and the inner side of the little fingers emerge from the Palmar fascia further back than the others. The nerves are superficial to the arteries at the clefts of the fingers. The origins of the vessels and nerves are not traceable at this stage. 6. The Ulnar artery and nerve are found beneath the Palmaris brevis muscle, lying at first upon the An- nular ligament, and then passing beneath the Palmar fascia. The nerve is on the Ulnar side of the artery. IIL Remove now the three portions of the Palmar fascia and the Superficial Transverse ligament. This must be done carefully, so as to avoid cutting the various vessels and nerves, which are now to be traced to their several origins. There will now be exposed — 1. The small muscles of the thumb. The Abductor most superficial. The outer head of the Flexor brevis along its inner border. A small piece of the Opponens along its outer border, close to the Annu- lar ligament. A small portion of the Adductor running transversely in the cleft between the thumb and index finger, internal to the Plexor brevis pollicis. 2. The small muscles of the little finger. The Abductor most internal. The Flexor brevis along the outer side of the preceding. THE DEEP PALMAR ARCH. 103 3. A small piece of the Abductor indicis muscle along the Radial side of the index finger, emerging from beneath the Adductor pollicis muscle. 4. The tendons of the Flexor sublimis digitorum muscle, entering their sheaths on the four fingers. 5. The four Lumbricales muscles, the first on the Radial side of the index tendon of the Flexor sublimis digitorum muscle, and the others in the intervals between the tendons. 6. The Superficial Palmar arch and its venae comites crossing transversely the Flexor tendons on a level with the upper border of the abducted thumb. It is formed for the most part by the Ulnar artery, and is completed internally by the Superficialis Volse branch of the Radial artery, and by a com- munication with the Radialis Indicis artery. The first of these two last vessels is usually very small and even inconstant, when present it passes over or through the short muscles of the thumb. From the convexity of the arch, which is directed towards the fingers, the Digital branches arise. These are four in number, a single one to the inner side of the little finger, and three others which bifurcate for the contiguous sides of the ring and little, and two next digits. From the concavity of the arch arise small branches to the palm, which have been divided. Close to the lower border of the Annular ligament the Profunda branch of the Ulnar artery arises, and is seen passing between the Flexor brevis and Abductor minimi digiti muscles. 7. Issuing from beneath the Flexor brevis and Adductor pollicis muscles, and lying upon the Abductor indicis muscle is seen the Radialis Indicis branch 104 A MANUAL OF DISSECTIONS. of the Radial artery, along the outer side of the first finger. The commencement of the Princeps Pollicis branch of the same artery may be seen just at the cleft of the thumb and index finger. 8. The Ulnar nerve is seen to divide close to the lower border of the Annular ligament into a Superficial and Deep branch. The Deep branch passes, with the corresponding branch of the Ulnar artery, between the Plexor brevis and Abductor minimi digiti muscles. The Superficial branch supplies an undi- vided offset to the inner side of the little finger, and a bifurcated branch to the contiguous sides of this digit, and \he next. This last branch also sends an offset of communication beneath the Ulnar artery to the Median nerve. The branches from the Superficial division of the Ulnar nerve to the Palmaris brevis, and integument of the inner border of the palm are, of course, divided. 9. The Median nerve is seen passing from beneath the lower border of the Annular ligament lying upon the Plexor tendons. Just at this point it is found to be flattened out, and divided into two parts of nearly equal size. Prom the outer part filaments are traceable to the Abductor, Opponens, and outer head of the Flexor brevis pollicis muscles, and the following Digital branches, — viz., two undivided, one for each border of the thumb, and a third also single, for the Radial border of the index finger. This last also supplies the outermost Lumbrical muscle. The inner division supplies two branches which bifurcate for the contiguous sides of the index and middle, and middle and ring fingers ; the outermost of these two supplies the next nv. THE DEEP PALMAR ARCH. 105 Lumbrical muscle, the innermost communicates with the Ulnar nerve, as mentioned above. The branches of the Median nerve lie beneath the Superficial Palmar arch. a. Divide now the Superficial Palmar arch, both inter- nally and externally, raise the included piece, draw it with the Digital branches toward the fingers, and fix it there. b. Cut through the Superficial branch of the Ulnar nerve, and throw it towards the fingers. c. Divide the Median nerve at the lower border of the Annular ligament, and bring it also over the fingers, cutting through its branches to the muscles of the thumb and two outer Lumbrical muscles. d. Cut through the origin of the Flexor brevis minimi digiti muscle from the Annular ligament and Unciform process, and throw it forwards. Its nerve from the Deep branch of the Ulnar will be divided. e. Remove the central portion of the Anterior Annular ligament with the portion of the tendon of the Palmaris longus muscle which passes over it. f. Cut through the tendons of the Flexor sublimis digitorum muscle, and throw them towards their respective fingers. Beneath the Annular liga- ment they will be found to be arranged in pairs, the two to the middle and ring fingers being superficial to the other two. There will now be exposed — 1. The Adductor minimi digiti muscle, beneath the Flexor brevis minimi digiti muscle. 2. The tendons of the Flexor profundus digitorum muscle, 106 A MANUAL OF DISSECTIONS. passing into the Digital sheaths beneath the Flexor sublimis tendons. 3. The Lumbricales muscles more fully. The two inner- most will be found arising from the contiguous sides of the tendons of the little, ring, and middle fingers. The two outermost from the Radial sides of the tendons of the middle and index fingers respectively. 4. Further portions of the Profunda branches of the Ulnar artery and nerve. Two slender twigs from this portion of the nerve are traceable to the two innermost Lumbricales muscles. V. a. Divide the tendons of the Flexor profundus digito- rum muscle, and throw them towards the fingers with the Lumbricales muscles attached. The nerves to the two innermost of these latter muscles from the Deep branch of the Ulnar will be torn through. b. Divide the origin of the Adductor minimi digiti from the Unciform process and Annular liga- ment, and turn the muscle inwards. Its nerve from the Deep branch of the Ulnar will be divided. There will now be exposed— 1. The Interossei muscles of the third and fourth spaces, a Palmar and Dorsal in each, the former on the Radial side of the latter. These muscles are covered by their fascia. 2. The Adductor pollicis muscle more fully, arising from the anterior two thirds of the Metacarpal bone of the middle finger, and passing outwards to the thumb. It hides the Palmar and Dorsal Interossei of the second space, except at their anterior ends. THE DEEP PALMAR ARCH. 107 3. The inner head of the Flexor brevis pollicis muscle, arising from the Trapezoid bone, the Oa Magnum, the base of the third Metacarpal bone, and the sheath of the Flexor carpi radialis tendon. It passes outwards to the thumb parallel with the upper border of the immediately preceding muscle. 4. The tendon of the Flexor longus pollicis muscle be- tween the two heads of the short Flexor. 5. The greater part of the Deep Palmar arch, i.e., the Deep branch of the Ulnar artery, is seen to join the Radial. 6. The Deep branch of the Ulnar nerve is seen accom- panying the corresponding branch of the artery, and ending in branches to the Adductor pollicis and the inner head of the Flexor brevis pollicis. Its twig to the Abductor minimi digiti muscle may be traced, but those to the Flexor brevis and the Adductor minimi digiti muscles are divided. Offsets to all the Interossei muscles may be found. VI. To complete the dissection — Remove the inner head of the Flexor brevis pollicis muscle from its origin, and throw it towards the thumb. Its nerves will be divided. This will expose — 1. The upper portions of the Palmar and Dorsal Inter- ossei of the second space. 2. A further portion of the Abductor indicis muscle, previously covered by the inner head of the Flexor brevis pollicis muscle. 3. The whole of the Deep Palmar arch, which will be found to be formed in this way. The Radial artery is seen entering the palm at the back of the first interosseous space, between the two heads of origin 108 A MANUAL OE DISSECTIONS. of the Abductor indicia muscle. It runs transversely across the palm, lying upon the bases of the Meta- carpal bones and the Interossei muscles, above the upper border of the Adductor pollicis muscle; and joins at the inner part the Deep branch of the Ulnar artery. It forms an arch about half an inch nearer the wrist than the superficial one. Prom its con- cavity Recurrent branches are traceable up to the wrist to join the Anterior Carpal arch. Prom its convexity proceed three arteries which occupy the three inner interosseous spaces, and run forwards to the clefts of the fingers to join the Digital branches of the superficial arch. Prom these Interosseous branches three Perforating offsets to the Interosseous arteries of the back of the hand are traceable. 4. Further portions of the Radialis Indicis and Princeps Pollicis arteries, previously covered by the inner head of the Plexor brevis pollicis, are displayed. A Dissection to Expose the Interosseous Artery, its Branches and their Anastomoses. Position. — Both surfaces of the forearm will be dis- sected, so that it must be pronated or supinated as occa- sion arises. I. Skin Incisions. 1. A circular incision round the arm, at the level of the external Condyle of the Humerus. 2. An incision more or less circular, which corre- THE INTEROSSEOUS ARTERY. 109 sponds in front to the line between the forearm and palm, but posteriorly runs a little lower down along the bases of the Metacarpal bones. 3. A median incision, joining the two preceding above and below, running down the anterior surface of the forearm. Remove the whole of the skin of the forearm between these limits, and expose the superficial fascia, containing — In Fbont — 1. The Median vein, its bifurcation into Median-cephalic and Median-basilic branches, and its junction at the division with the Deep Median branch communi- cating with the venas comites of the Brachial artery. 2. The Radial vein commencing below at the back of the forearm, but soon winding round the outer border and joining above the Median-cephalic vein. 3. The Anterior Ulnar vein running up the inner border of the forearm, receiving above the Posterior Ulnar vein, which lower down is placed on the posterior surface, but above winds round to the front to join the Anterior Ulnar vessel. The vein resulting from this junction is seen entering the Median-basilic. 4. The anterior branches of the Internal Cutaneous nerve, some of which usually pass over, and some beneath the Median-basilic vein to supply the skin of the inner border of the forearm as far as the wrist. 5. The anterior branch of the External Cutaneous nerve, usually passing beneath the Median-cephalic vein and supplying the skin of the outer part of the forearm, within the whole limits of the surface exposed. 6. Twigs of the upper External Cutaneous branch of the Musculo-spiral nerve reach the upper and outer 110 A MANUAL OF DISSECTIONS. part of the anterior surface of the bend of the elbow. 7. The Palmar Cutaneous branch of the Median nerve is seen piercing the fascia about the centre of the fore- arm just above the wrist. 8. The Palmar Cutaneous branch of the Ulnar nerve lies over the line of the Ulnar artery, and pierces the fascia lata just above the wrist. Sometimes a second branch is cutaneous higher up, and joins the anterior branch of the Internal Cutaneous nerve. Behind — 9. The lower portions of the Radial and Posterior Ulnar veins, as mentioned above. 10. The posterior branch of the Internal Cutaneous nerve, supplying about the upper half of the internal por- tion of the forearm. 11. The posterior branch of the External Cutaneous nerve supplying about the lower third of the outer border of the forearm. 12. Twigs of the lesser Internal Cutaneous nerve, between the internal Condyle and the Olecranon process, and a junction with the posterior branch of the In- ternal Cutaneous nerve. 13. The lower External Cutaneous branch of the Musculo- spiral nerve, supplying the skin of the back of the forearm, between the Internal and External Cuta- neous nerves as far as the wrist, and communicating with the latter. 14. The Radial nerve, cutaneous between from two to three inches above the wrist, and its points of divi- sion into branches for the thumb, the next two, and half the ring fingers. THE INTEROSSEOUS ARTERY. Ill 15. The Dorsal branch, of the Ulnar nerve, perforating on the inner side at a lower point than the Radial, and its points of division into branches for the remaining finger and a half. IIII. a. Remove the preceding, and expose the fascia lata, joined above in front of the bend of the elbow, by the semilunar process from the tendon of the Biceps muscle. Behind the wrist it is seen to be strengthened by transverse fibres, and to consti- tute the Posterior Annular ligament. b. Clear away the deep and Bicipital fascia, and expose — In Feont — 1. Above, the lower part of the triangular space of the bend of the elbow, bounded : externally, by the Supinator longus muscle ; internally, by the Pronator radii teres muscle ; and having the floor formed by the lower part of the Brachialis anticus muscle and a small portion of the Supinator brevis muscle. It contains — 2. The tendon of the Biceps muscle running down to the Tuberosity of the Radius, most externally. 3. The Brachial artery, surrounded by its venae comites, placed internal to the Biceps tendon. The division of the artery into Radial and Ulnar branches is seen, and the commencement of the Badial Eecurrent branch. 4. The Median nerve is exposed inside the artery, and its branch to the Pronator radii teres muscle may be traced. 5. Internal to the Pronator radii teres muscle is seen the Flexor carpi radialis muscle, as far as the wrist. 112 A MANUAL OF DISSECTIONS. 6. The Palmaris longus muscle, next internally, and 7. The Flexor carpi ulnaris muscle, innermost of all. 8. At the wrist between the tendons of the two preceding muscles, those of the Flexor sublimis digitorum muscle come into view. 9. Small portions of the Pronator quadratus muscle are seen below on the Eadius and Ulna. 10. The Radial artery and its venae comites are exposed farther than has been indicated above, — viz., as low down as the wrist. At first it lies in the triangular space, then crosses over the insertion of the Pronator teres muscle, and finally lies between the Supinator longus and Flexor carpi radialis tendons. •11. The Ulnar artery with its veins is seen for about its lower third, below and internally, passing from beneath the fleshy portion of the Flexor carpi ul- naris muscle, and running on the outer side of its tendon as far as the wrist. 12. The Radial nerve is seen external to its artery, as far as about three inches above the wrist. It is overlapped above by the fleshy part of the Supi- nator longus muscle. 13. The Ulnar nerve lies on the inner side of the lower exposed portion of the corresponding artery, as far as the wrist. 14 A further small portion of the Median nerve is seen, just above the wrist, between the Flexor carpi radialis and outermost tendon of the Flexor sub- limis digitorum. Behind — 15. The Anconeus muscle, passing between the external - Condyle, and the outer surfaces of the Olecranon THE INTEROSSEOUS ARTERY. 113 process and the upper part of the shaft of the Ulna. The following muscles from without inwards — 16. The Supinator longus. 17. The Extensor carpi radialis longior. 18. The Extensor carpi radialis brevior. 19. The Extensor communis digitorum. . 20. The Extensor minimi digiti. 21. The Extensor carpi ulnaris. At the lower part, passing out between the Extensor communis digitorum and Extensor carpi radialis brevior tendons, are — 22. The Extensor ossis metacarpi and primi internodii pollicis muscles. 23. The Posterior Interosseous artery is seen on the outer side of the Extensor carpi ulnaris tendon for about the lower third of the forearm, accompanied by its vein. III. Iu Fboht — a. Divide the Pronator radii teres muscle at its inser- tion, and at its origin from the Coronoid process, and pull it upwards, cutting through at the same time the Anterior Ulnar Recurrent artery and the Median nerve. b. Cut through the tendons of the Palmaris longus and Flexor carpi radialis muscles at the wrist, and pull these muscles upwards. Their nerves from the Median will be divided, and arterial twigs from the Radial and Ulnar. There will now be exposed — 1. The Flexor sublimis digitorum muscle, its origin above from the internal Condyle, the inner side of the I 114 A MANUAL OF DISSECTIONS. Olecranon, the oblique line and npper three fourths of the anterior border of the Radius; and its tendons below as far as the wrist. 2. A small • portion of the tendon of the Flexor longus pollicis muscle below, lying upon the lower part of the Radius. 1^. Divide the fleshy belly of the Flexor sublimis digitorum muscle by a longitudinal incision along the middle line, and hook the halves inwards and outwards. The Median nerve has already been cut, but branches from it to this muscle and arterial twigs from the Ulnar will be divided. There will now be exposed — 1. The Flexor profundus digitorum muscle, lying upon the Ulna and the corresponding half of the Interos- seous membrane. 2. The Flexor longus pollicis muscle, concealing the an- terior surface of the Radius and the outer part of the Interosseous membrane. Its occasional head from the inner part of the Coronoid process will be seen if present. 3. A further portion of the Ulnar artery is now seen lying upon the Brachialis anticus and Flexor profun- dus digitorum muscles, and the following branches : the Anterior and Posterior Ulnar Recurrent branches, the former being cut, the Common Interosseous trunk giving off Anterior and Posterior Interosseous branches, the former seen passing between the Flexor profundus and longus pollicis muscles, and the latter going to the back of the forearm. 4. All these arteries have corresponding veins. 5. The Median nerve lying upon the Flexor profundus muscle, accompanied by the G. Comes nervi Mediani artery at the lower part. THE INTEROSSEOUS ARTERY. 115 V. Separate now the Flexor longus pollicis muscle from the Flexor profundus digitorum muscle, dissect off their origins from the Interosseous membrane, and pull the former well outwards and the latter inwards. The occasional head of origin of the Flexor longus pollicis must be cut through if present. There will now be exposed — 1. The Interosseous membrane. 2. The Pronator quadratus muscle in the greater part of its extent. 3. The Anterior Interosseous artery lying upon the mem- brane, and disappearing below beneath the Pronator quadratus muscle. Its twigs to the muscles between which it lies, the origin of the Comes nervi Mediani artery, and the nutrient arteries to the Radius and Ulna may now be traced from it. The Posterior Interosseous artery may be traced above, passing to the back of the forearm between the Oblique liga- ment and the upper margin of the Interosseous membrane. 4. The Anterior Interosseous nerve is found with the artery of the same name, and its several branches to the Flexor profundus and longus pollicis muscles - are traceable, if they have not been torn through in separating these muscles. VI. To expose the artery beneath the Pronator quadratus •muscle, one of two courses may be taken, viz., A or B. (A) a. Separate the tendons of the Flexor profundus muscle well from that of the Flexor longus pollicis muscle as far as the upper border of the An- terior Annular ligament, and draw them by hooks on either side. b. Divide the Pronator quadratus muscle longitudi- 116 A MANUAL OF DISSECTIONS. nally, and reflect the halves inwards and out- wards. In this way there will be exposed — 1. The anterior surface of the wrist-joint and its liga- ments. 2. The Anterior Carpal arch, derived from the Radial and Ulnar arteries. 3. The Anterior Interosseous artery passing to the back of the forearm beneath the Interosseous membrane, but sending down a branch to anastomose with the Anterior Carpal arch. (B) a. Divide the tendons of the superficial and deep Flexor muscles of the fingers at the Annular liga- ment, dissect them up for some distance and hook them inwards. The same parts enumerated under A will be ex- posed, but more completely. The Anterior Interosseous artery is now fully exposed except at its ending. To see this, and to trace the Pos- terior artery, the forearm should now be supinated. The structures exposed by the removal of the fascia lata have been enumerated under Section II. Behind — VII. a. Remove the Posterior Annular ligamenj. b. Separate the Extensor communis digitorum muscle from the Extensor carpi radialis brevior muscle as high as the external Condyle, cut through its Condyloid origin and reflect the muscle down- wards as far as the bases of the Metacarpal bones. c. Cut through the origin of the Extensor minimi digiti, and reflect it down to the same extent. THE INTEROSSEOUS ARTERY. 117 d. Divide the origin of the Extensor carpi ulnaris from the external Condyle and the deep fascia as low down as its attachment to the posterior margin of the Ulna, and hook the muscle inwards. Branches of the Posterior Interosseous nerve will be cut through in the division of these muscles, together with twigs from the artery of the same name. e. Remove the Anconeus muscle, taking care of the artery which will be found beneath it. There will now be exposed — 1. The posterior surface of the Supinator brevis muscle, highest of all. 2. Next below, the Extensor ossis metacarpi pollicis muscle, arising from the Eadius and Ulna. 3. Next, the Extensor primi internodii pollicis muscle, arising from the Radius. 4. Still lower, the Extensor secundi internodii pollicis muscle, arising from the Ulna. 5. Lowest of all, the Extensor indicis muscle, from the Ulna. 6. The Posterior Interosseous artery, passing from the front, between the Supinator brevis and Extensor ossis metacarpi pollicis muscles, and running down the forearm along the outer side of the tendon of the Extensor carpi ulnaris, lying upon the other Ex- tensors of the thumb, and that of the index finger. The Recurrent branch uncovered by the removal of the Anconeus muscle is seen passing upwards, lying first upon the Supinator brevis muscle and then upon the Ulna, anastomosing above with the pos- terior branch of the Superior Profunda artery, and communicating across the Olecranon with the Pos- 118 A MANUAL OF DISSECTIONS. terior TJlnar Recurrent artery. The corresponding veins are seen. 7. The Posterior Interosseous nerve is displayed, coming through the Supinator brevis muscle, dividing into branches for the Extensor muscles, and disappear- ing below beneath the Extensor secundi internodii pollicisi VIII. Divide now the Extensor secundi internodii pollicis and Extensor indicis muscles. Remove the fleshy portions and pull the tendons outwards. This will expose — 1. The termination of the Anterior Interosseous artery. 2. The Posterior Carpal arch. 3. The communication between the two preceding, and the branch from the Posterior Interosseous artery, which joins the Anterior, and the Carpal arch. 4. The further portion of the Posterior Interosseous nerve, and its gangliform enlargement. IX. To see the origin of the Posterior Interosseous artery from the common trunk, remove, if necessary, a portion of the lower margin of the Supinator brevis muscle. A Dissection to Expose the Obturator Nerve completely. Position. — The body supine, the thigh of the side dissected to be abducted, rotated out, and slightly flexed. I. The Abdomen is to be opened by a crucial incision, and the lower flap on the side to be dissected removed by an incision parallel with and a little above the line of Pou- THE OBTUEATOE NERVE. 119 part's ligament, then inwards to the median line, the other flaps to be turned outwards and fixed. In the flap cut away there will be removed the follow- ing structures in layers, lettered A, B, C 3 ~D, E, F, G, H, K. 1 No. 14. A. Skin. B. Superficial fascia in two layers at the lower part. 1 Paragraphs A, B, C, D, E, F, G-, H, K have been printed in smaller type because the anatomy of this flap is not an essential part of the dissection : nevertheless, it is a good plan to mention every structure divided or removed which is visible to the naked eye. 120 A MANUAL OP DISSECTIONS. Superficial Pudic artery and vein passing inwards over the cord. Superficial Epigastric artery and vein passing upwards over the centre of Poupart's ligament. Superficial Circumflex Iliac artery and vein, sending twigs over the lower part of the Abdomen at the outer part. Ilio-hypogastric nerve, cutaneous about one inch above the external Abdominal ring. Eio-inguinal nerve coming through the ring. Lymphatic glands along Poupart's ligament. One or two of the lower Anterior Cutaneous nerves ac- companied by twigs of the Deep Epigastric artery. The Spermatic cord emerging at the ring. C. The aponeurosis of the External Oblique muscle, with the following parts : — External ring above and outside the spine of the Pubes. Intercolumnar fibres crossing transversely the lower fibres of the aponeurosis, which run downwards and inwards, and the fascia of the same name covering in the ring. «The Triangular fascia belongs to this muscle, but is seen in the next layer as it runs up beneath the inner pillar of the ring to the Linea alba. The anterior layer of the sheath of the Rectus muscle is seen more internally, consisting partly "of the aponeu- rosis of the External Oblique muscle and partly of the next. D. The Internal Oblique muscle in its origin from about the outer half of Poupart's ligament and part of its origin from the crest of the Ilium, and in its insertion to the Linea alba and crest of the Pubes forming the rest of the anterior layer of the sheath of the Eectus muscle as far as half way between the Umbilicus and Pubic crest, but reinforced by the aponeurosis of the Transversalis muscle below that point. Above this the aponeurosis splits into two layers, one of which passes in front and one behind the Eectus muscle. The Conjoined tendon of this, and the next succeeding muscle at its insertion into the Ilio-pectineal line. THE OBTURATOR NERVE. 121 The Cremaster muscle in front of the cord. Further portions of the Ilio-hypogastric and Ilio-inguinal nerves which lie between the Oblique muscles. A further portion of the cord. E. The Transversalis muscle, in its origin from the outer third of Poupart's ligament, and part of its origin from the Iliac crest, and its insertion into the Linea alba and Pubic crest, forming the rest of the anterior layer of the sheath of the Rectus muscle below the point indicated, but above that extending into the Linea alba behind the muscle. The fascia Transversalis outside the Conjoined tendon and its Infundibuliform process hiding the internal ring. F. The Rectus and Pyramidalis muscles, the latter in front of the lower part of the former. G. The fascia Transversalis. The Deep Epigastric vessels running up internal to the ring and behind the Rectus muscle, giving off and re- ceiving the Pubic branches. The Deep Circumflex Iliac vessels, running out parallel with Poupart's ligament. ► The obliterated Hypogastric artery, corresponding in its position with the Epigastric, but on its deep surface. H. Subperitoneal fat. K. Peritoneum. II. NOW DISSECT THE PART OF THE NERVE IN THE THIGH. Skin Incisions. 1. From the crest of the Pubes at the centre, down the Symphysis and along the inner part of the thigh to the posterior part of the internal Condyle of the Femur. 2. Transversely from the lower end of the' preceding to the fore part of the Condyle. Reflect the flap outwards as far as the line of the Fe- moral artery. 122 A MANUAL OF DISSECTIONS. This exposes the superficial fascia which below Pou- part's ligament internal to the Saphenous vein, is found to consist of two layers. At this point it conceals the Saphenous opening, and being perforated by lymphatics is called the Cribriform fascia. 1 This fascia contains the following — 1. The Long Saphenous vein, running up along the inner and front part of the thigh, and receiving at the upper part the Superficial Fudic, Epigastric, and Circumflex Iliac branches, and the cutaneous veins of the inner and back part of the thigh united into one trunk, which enters the Saphenous near the opening of that name. Sometimes the veins of the outer part of the thigh unite in a similar manner and join it near the same spot. 2. The cut ends of the Superficial Pudic, Epigastric, and Circumflex Iliac arteries, and a cutaneous twig of the Anastomotica Magna artery in front of the inner Condyle. 3. The branch of the Ilio-inguinal nerve to the skin of the upper and inner third of the thigh. 4>. The Internal Cutaneous nerve perforating the fascia lata at the junction of the lower with the middle third. Smaller twigs of the nerve are cutaneous above this along the Saphenous vein, one or two about the Saphenous opening, and another half-way down. 5. Numerous lymphatic vessels in the front of the thigh, and a chain of glands along Poupart's ligament. III. Remove and expose — 1. Poupart's and Gimbernat's ligaments. 2. The fascia lata of the thigh, presenting at the upper 1 This is the deeper of the two layers. THE OBTURATOR NERVE. 123 and inner part, immediately below Poupart's liga- ment, the Saphenous opening. IV. Clear these structures away and expose — 1. The Pectineus muscle at the upper and outer part of the dissection. 2. If this muscle be separated from the next succeeding, the Adductor brevis muscle is seen in small part, and lying upon it the three muscular branches of the Superficial division of the Obturator nerve. 3. The Adductor longus muscle below and internal to the preceding. A branch of the Superficial division of the Obturator nerve is found lying along its inner border. 4. The Gracilis muscle most internal, descending from the Ramus of the Pubes and flattened against the Adductor muscles. 5. The Adductor magnus muscle, the lower fleshy fibres and tendon, below the Adductor longus muscle. 6. The Sartorius muscle at the lower part of the thigh, external to the Adductors longus and magnus muscles. 7. A small piece of the Vastus internus muscle, external to the Adductors longus and magnus, and over- lapped below by the Sartorius muscle. 8. The special funnel-shaped sheath of the Femoral ves- sels is seen above, reaching for two inches below Poupart's ligament. This may now be cleaned away at once, and then the Femoral artery with the vein internal to it may be seen until they are covered by the Sartorius muscle. The Inferior External Pudic branch is seen passing inwards over the Pectineus, and the ending of the Deep 124 A MANUAL OF DISSECTIONS. branch of the Anastomotica Magna artery lying with the tendon of the Adductor magnus muscle. The vein corresponding to the Inferior Pudic branch is cut inasmuch as it joins the Saphenous. 9. The Deep Crural arch will be removed as it crosses the upper part of the Femoral sheath. V. a. Divide the Sartorius muscle now where it appears beneath the skin at the outer part. The branch of the Obturator nerve which runs along the Ad- ductor longus muscle may now be traced to its junction with the inner branch of the Internal Cutaneous nerve which is now exposed. The aponeurotic covering of Hunter's Canal will now be seen, and may be at once removed. When this is done, the Femoral artery may be traced to the opening in the Adductor magnus muscle. At this point it is seen to give off the Anastomotica Magna branch. The Femoral vein will be found now lying external to the artery. The Long Saphenous nerve will also be seen usually lying externally to the artery, but it may be crossing to the inner side. A communication between the inner branch of the Internal Cutaneous and Long Saphenous nerves may now be traced, thus completing the Obtu- rator plexus. b. Detach the Pectineus muscle from its origin and pull it outwards. c Cut through the Adductor longus muscle at its origin and pull it outwards, taking care of its nerve from the Superficial division of the Obtu- rator. There will now be exposed — THE OBTURATOR NERVE. 125 1. The Tipper part of the Obturator externus muscle be- low the horizontal Ramus of the Pubes. 2. The Adductor brevis muscle, below this and over- lapping it internally. 3. A further portion of the Adductor magnus muscle still lower. 4. The lesser Trochanter of the Femur, above the upper border of the Adductor brevis muscle. 5. The portion of the Profunda Femoral artery which lies beneath the Adductor longus. Its Perforating branches are seen, the first and second piercing the Adductor brevis muscle, the third and the terminal branch of the artery, the Adductor magnus muscle. 6. Branches of the Internal Circumflex artery, super- ficial to the Adductor brevis muscle. 7. The corresponding veins with the preceding arteries. 8. The Superficial division of the Obturator nerve, run- ning down over the Obturator and Adductor brevis muscles, and sending branches to the Gracilis, Ad- ductor longus and brevis muscles, and the Obturator plexus ; all of which are now displayed. A ter- minal twig to the Femoral artery may also be traced. VI. Divide the Adductor brevis muscle at its insertion. Re- move the branches of the Internal Circumflex vessels super- ficial to it. Pull the muscle inwards and fix it. In this way the branches of the Superficial division may be pre- served. There will now be exposed — 1. A further portion of the Adductor magnus muscle. 2. Other branches of the Internal Circumflex vessels beneath the Adductor brevis muscle. 3. The Deep division of the Obturator nerve may be traced. Branches may be followed to the Obtu- 126 A MANUAL OF DISSECTIONS. rator externus and Adductor magnus muscles, and to the Adductor brevis muscle, when it is not sup- plied by the Superficial division, A branch may be traced through the fibres of the Adductor magnus muscle to the Popliteal artery by removing a por- tion of the muscle and pulling internally the Semi- membranosus tendon. It may in this way be fol- lowed to the Posterior ligament of the knee-joint. VII. The abdominal- portion of the dissection SHOULD NOW BE RESUMED. a. The great Omentum and transverse Colon should be placed upon the ribs, and the Intestines turned to the opposite side of the body on which the dissection is made. b. Clear away the Peritoneum from the brim of the Pelvis, and that over the posterior wall of the Abdomen from near the median line to the right or left Colon, as the case may be. c; Divide the junction of the Rectum with the Sigmoid flexure, or the Ileum with the Caecum, according to the side dissected. d. Cut through the constituents of the cord at the interna] Abdominal ring if this has not already been done, viz., the Vas Deferens, the Spermatic vessels, and Sympathetic nerves. The artery to the Vas from the Superior Vesical. There will now be exposed — 1. The Psoas magnus muscle, and parvus if present. 2. The Iliacus muscle in the Venter Ilii, covered by its fascia. 3. The Common Iliac artery and its bifurcation, the upper part of the Internal, and the whole of the THE OBTURATOR NERVE. 127 External Iliac branch running along the brim of the Pelvis and continuous with the Femoral. 4. The corresponding veins. 5. The Sigmoid branch of the Inferior Mesenteric artery or the Ileo-colic of the Superior will be seen, accord- ing to the' side dissected, crossing the Psoas muscle, with their veins. 6. The Ureter and Spermatic vessels will be found de- scending over the Psoas muscle. 7. The Genito-crural nerve lying upon the Psoas muscle, and traceable below to the Femoral artery and the internal ring. 8. The Anterior Crural nerve between the Psoas and Iliacus. 9. The External Cutaneous nerve crossing the Iliacus muscle. Till. a. Remove the Sigmoid or Ileo-colic vessels, as the case may be. b. Cut through the External Iliac vessels at their upper ends, and pull the lower outwards. c. Separate the Pelvic fascia from the brim and upper part of the Pelvic wall. The Obturator nerve, artery, and vein, in this order, from above down- wards, will be found running along the outer wall of the Pelvis to the opening in the Thyroid foramen ; parallel and internal to its upper part will be found the large cord passing from the fourth to the fifth Lumbar nerves, and between this and the Obturator the Ilio-lumbar artery and vein. d. Pull the Ureter inwards, and the Spermatic vessels outwards from off the Psoas, and remove the inner part of this muscle from its origin as far up- 128 A MANUAL OF DISSECTIONS. wards as the lower border of the second Lumbar vertebra downwards to the Pelvic brim. e. Remove a piece of the horizontal Ramus of the Pubes, from just outside the Pubic spine for an inch and a half, opening in this way the canal at the upper part of the Thyroid foramen, dividing and re- moving a portion of the Obturator externus muscle and membrane. There will now be exposed — 1. The origin, course, and distribution of the Obturator nerve. The branch from the Superficial division to the hip-joint which comes off near to the Thyroid membrane being now traceable. In the dissection made the Obturator trunk arose from the second, third, and fourth Lumbar nerves. 2. The origin and commencement of the Anterior Crural nerve. 3. The bodies of the third, fourth, and fifth Lumbar vertebrae, and the intervertebral disc between the second and third. 4. The Aorta, and second, third, and fourth Lumbar arteries. 5. The Renal vessels of the side dissected, at the upper part. 6. Further portions of the Ilio-lumbar vessels. 7. The gangliated cord of the Sympathetic nerve lying on the side of the vertebrse, and the communications between the ganglia and Lumbar nerves. 8. The communication between the fourth and fifth Lumbar nerves, and the commencement of the Lumbo-sacral cord. 9. The remaining portion of the Psoas muscle. 10. The Iliacus muscle covered by its fascia. THE PORTAL VEIN. 129- 11. Lying upon the Psoas muscle the Genito-crural, and upon the Iliacus muscle the External Cutaneous nerves. A Dissection of the Portal Vein, and its Branches. Position. — The body lying on its back. I. The Abdomen being opened by a crucial incision, the parts exposed will be — 1. The Stomach. 2. The Liver and Gall-bladder. 3. The great Omentum descending from the Stomach and hiding the small Intestines ; frequently, however, it is more or less puckered up, and exposes them to a variable extent. 4. The Caecum and the lower end of the ascending Colon when distended. II. Fix the Liver to the ribs by stitches passed through its substance. Pull down the Pylorus and dissect out the structures in the lesser Omentum, viz. — 1. The Bile duct to the right, above joined by the Cystic and Common Hepatic branches. 2. The Hepatic artery to the left, giving off the Superior Pyloric, Cystic, and Gastro-duodenal branches, the last running down behind the Pylorus, and giving off the Inferior Pyloric branch. 3. The Portal vein behind the preceding, dividing into right and left branches, and the right re- ceiving the Cystic vein. The Gastric vein should be traced into it at the Pylorus. The Gastro- epiploic vein, running along the greater curva- K 130 A MANUAL OF DISSECTIONS. ture of the Stomach, may be traced into the Gastro-duodenal by pulling down the Pylorus, and the junction of this with the Portal after being- joined by the Pancreatico-duodenal vein may be seen. III. Place the great Omentum on the ribs, and dissect out — 1. The Superior Mesenteric vein by placing the Intes- tines over on the left side and removing the ante- rior layer of the Mesentery. The branches from small Intestines, the Ileo-colic, and right Colic branches may be found, and the middle Colic by removing the lower layer of the transverse Meso- colon. 2. The Inferior Mesenteric vein, by placing the Intes- tines on the right side and removing the Perito- neum covering the left side of the posterior Abdominal wall, whence it passes over the Colon. The left Colic, Sigmoid, and beginning of the Supe- rior Hemorrhoidal branches will be seen. In this dissection the corresponding arterial branches, the Superior and Inferior Mesenteric plexuses of the Sympathetic nerve and the Mesenteric glands will be seen, and the arte- ries and veins occupying the following relative posi- tions : — a. Superior Mesenteric vein to the right. 6. Superior Mesenteric artery to the left of preceding. c. Nest the Inferior Mesenteric artery. d. The Inferior Mesenteric vein, most to the left. IV. Remove any remaining parts of the posterior layer of the transverse Meso-colon. Divide a small piece of the upper end of the Mesentery opposite the second Lumbar THE KIDNEY. 131 vertebra, in order to get the beginning of the Jejunum to the right, as it overlaps the upper end of the Inferior Mesenteric vein. V. Divide the Hepatic flexure of the Colon, and, pulling the divided ends to the right and left sides, pin them there. This exposes — 1. The Pylorus and Duodenum encircling the Pancreas. 2. The Superior and Inferior Mesenteric arteries and veins passing over the third piece of the Duodenum and beneath the Pancreatic gland. VI. a. Divide now the head of the Pancreas, and the Duo- denum at the junction of its first and second portions. The arteria Pancreatic Magna will be divided as well as the duct. b. Pull the Stomach and Pancreas over to the left, and place them on the ribs. e. Remove the Hepatic artery and Bile duct. The Portal vein and its branches will now be fully seen. A Dissection of the Posterior Surface of the Kidney. Position. — The body lying upon its face. I. Skin Incision's. 1 1. Prom the spine of the twelfth Dorsal vertebra, transversely outwards to the tip of the last rib. 1 It may be objected that these incisions will not uncover a suffi- cient surface to expose the Kidney. The writer has always pro- ceeded on the principle of the least possible destruction of surround- 132 A MANUAL OF DISSECTIONS. 2. From the spine of the fourth Lumbar vertebra transversely outwards to the crest of the Ilium, and along it to a point midway between the anterior and posterior Iliac spines. 3. A longitudinal incision along the median line from the spine of the twelfth Dorsal to the fourth Lumbar vertebra. No. 15. Reflect the flap outwards and expose the superficial fascia, containing — 1. The external branches of the posterior primary divi- sions of the eleventh and twelfth Dorsal nerves at the tipper part, about one inch from the median line. The branch from the twelfth nerve external to the other. 2. The posterior branches of the Lateral Cutaneous offsets of the tenth and the eleventh Dorsal nerves extend- ing backwards at the anterior and upper part. 3. The external branches of the posterior primary divi- ing parts, compatible with a full view of the structure to be displayed, and he has found from repeated dissections of the Kidney that these incisions are ample. THE KIDNEY. 133 sions of the first, second, and third Lumbar nerves passing over the crest of the Ilium, the Tipper ones supplying filaments to the skin over the lower part of the space between the last rib and the crest of the Ilium. 4. Small cutaneous branches from the Intercostal arteries with the posterior and lateral cutaneous nerves, and from the Lumbar arteries with the Lumbar nerves. II. Remove the preceding and the fascia lata, and ex- pose — The aponeurosis of the Latissimus dorsi muscle attached to the Lumbar spines and about the posterior half of the crest of the Ilium. Fleshy fibres of the muscle are seen for an inch or more in front of the aponeurotic Iliac attachment of the muscle, and also at the upper part. III. Cut through the Latissimus dorsi muscle at its attach- ment to the Iliac crest, and again along the upper border of the twelfth rib. Join these transverse cuts by a longi- tudinal one through the muscle between their outer ex- tremities. Reflect the muscle inwards as far as possible towards the median line behind. There will now be exposed — 1. The Serratus posticus inferior muscle running from the spines of the last Dorsal and upper two or. three Lumbar vertebrae upwards and outwards, and its attachment to the last rib will be seen. 2. The posterior layer of the aponeurosis of the Trans- versalis muscle will be seen below. These three aponeurotic structures, viz., the origins of the Latissimus dorsi and Serratus posticus inferior 134 A MANUAL OF DISSECTIONS. muscles, and the posterior lamella of the aponeurosis of the Transversalis are all more or less conjoined with one another at their attachments to the Lumbar spines. The united aponeurosis constitutes the Fascia lumborum. 3. The outer edge of the Fascia lumborum will be found to be marked by a definite vertical line, which later on is seen to correspond to the external border of the Erector spinas muscle. Outside this, the fleshy- origin of the Internal Oblique muscle, from the middle layer of the posterior aponeurosis will be seen. 4. More externally still, the posterior free edge of the External Oblique muscle will be seen, extending from the last rib to the Iliac crest, having internal to it the cut edge of the Latissimus dorsi muscle. 5. The outer portion of the last rib will be seen above, and probably, owing to the retraction of the skin, the lower fibres of the last External Intercostal muscle. IV. a. Clear away completely the Lumbar fascia. b. Detach the Internal Oblique muscle from its origin, and turn it outwards. There will now be exposed — 1. Nearest to the median line the Erector spinse muscle, dividing above into Sacro-lumbalis externally, and Longissimus dorsi muscles internally, at about the level of the last rib. 2. Internal to the Longissimus dorsi muscle, from the twelfth Dorsal and upper two Lumbar spines, the Spinalis dorsi muscle passing upwards. 3. External to the Erector spinas muscle, the cut edge of the posterior layer of the aponeurosis of the Trans- THE KIDNEY. 135 versalis muscle. Outside this the middle layer, and, still more externally, the undivided aponeurosis and the fleshy fibres of the muscle. 4. Still more externally, the divided Latissimus dorsi and the External Oblique muscles, as before. 5. Resting upon the upper part of the Erector spinas the external branches of the posterior primary divi- sions of the eleventh and twelfth Dorsal nerves, and, piercing its outer border, the corresponding branches of the upper three Lumbar nerves. 6. The anterior branch of the last Dorsal nerve with its accompanying vessels piercing the aponeurosis of the Transversalis muscle at the outer part. V. The further progress of the dissection will depend upon the width of the Erector spinas muscle. Usually it will be necessary to remove it, or at least the outer part, but the muscle may be narrow, and then it may be cut transversely at the level of the last rib, and drawn inwards sufficiently. It will be well to proceed as follows : — a. Make a transverse cut into the upper part of the Erector spinae muscle, and draw the muscle well inwards towards the spines of the vertebra?. b. Remove the middle layer of the Transversalis apo- neurosis and the fleshy fibres of the muscle by vertical cuts, externally and internally. The last Dorsal vessels and nerve may be dissected out and left. There will now be exposed, in addition to the structures enumerated under Stage IV. — 1. The tips of the transverse processes of the four upper Lumbar vertebrae. 2. The Quadratus lumborum muscle. 3. Resting upon the posterior surface of the Quadratus 136 A MANUAL OF DISSECTIONS. lumborum muscle the anterior branches of the four Lumbar arteries, but the lowest may pass in front. With the arteries are the corresponding veins. VI. Take away now the Quadratus lumborum muscle completely, with the vessels lying upon it. There will now be exposed, in addition to the structures already enumerated — 1. The anterior layer of the aponeurosis of the Trans- versalis muscle. 2. Further portions of the last Dorsal vessels and nerve ; lying immediately below the last rib. VII. Kemove the anterior lamella of the aponeurosis of the Transversalis muscle and a quantity of adipose tissue, and there will be displayed — 1. The posterior surface of the Kidney. This organ is very movable, and enveloped by fat. The writer has found as the result of several dissections that, putting for the moment on one side the question of the removal of the Erector spinEe muscle, the Kidney will now fall forwards, and the whole of its posterior surface may be now cleaned and exposed, and that the removal of the eleventh and twelfth ribs is entirely unnecessary. Besides the Kidney there will be displayed — • 2. The Pelvis of the Kidney and the commencement of the Ureter. 3. The Colon ascending or descending according to the side dissected. On the left side it lies below and external to the Kidney, on the right more im- mediately below. Arteries and veins from and to the Superior or Inferior Mesenteric vessels, as the case may be, can also be traced to the Intestine. THE KIDNEY. 137 4. The Peritoneum and subperitoneal fat will be seen outside the preceding viscera. 5. Crossing the Kidney transversely from above down- wards will be seen — The anterior branches of the last Dorsal vessels and nerve. The Ilio-hypogastric nerve. The Ilio-inguinal nerve. 6. Internally the outer part of the Psoas magnus muscle. 7. Above, the origin of the Diaphragm from the liga- mentum Arcuatum externum. VIII. The dissection has been given from Stage V. on the supposition that the Erector spinae muscle was sufficiently narrow to allow of its being drawn inwards after making a transverse cut at the upper part. This the writer knows from experience to be the case some- times. Nevertheless, it more often happens that the muscle is too wide to admit of this mode of treatment, and when this is the case the following correction must be made for Stage V. : — Remove the Erector spinas muscle as far as it is exposed in the dissection. In addition to the structures already enumerated, there will now be displayed — 1. The inner half of the twelfth rib, and the transverse processes of the four upper Lumbar vertebrae. 2. The attachment to the last rib of the twelfth Le- vator costae muscle between the tubercle and the angle. 3. The Multifidus spinae muscle, arising from the mammillary processes of the Lumbar vertebrae and passing upwards and inwards to the spinous pro- cesses. 138 A MANUAL OF DISSECTIONS. 4. The posterior Inter-transverse muscles between the transverse processes. 5. The posterior primary division of the last Dorsal nerve and the accompanying vessels. A Dissection to Expose the Posterior Surface of the Sacral Plexus. Position. — The body lying on the face, the Abdomen and Pelvis raised on blocks, allowing the legs to hang down to a moderate extent. I. Skin Incisions. 1. An incision running horizontally outwards for four inches from the median line, at a level of one inch above the posterior superior Iliac spine. 2. From the inner end of (1) along the median line, three-fourths of the distance to the tip of the Coccyx. 3. Prom the lower end of (2) obliquely downwards and outwards to the Tuber Ischii. Reflect the flap outwards and expose — 1. The loose areolar tissue of the buttock, and in it, 2. The external branches of the posterior primary divi- sions of the upper two Sacral nerves, the superior near the top of the Sacrum, the inferior at the lower part of the dissection. 2. Accompanying the preceding nerves cutaneous branches of the Lateral Sacral arteries. 4. Cutaneous branches of the Gluteal and Sciatic arteries over the Sacrum, and the Coccygeal branch of the latter at the lower part of the bone, also branches SACRAL PLEXUS FROM BEHIND. 139 of the Gluteal artery perforating the Gluteus maximus muscle. 5. Small filaments of the external branches of the posterior primary divisions of the upper three Lumbar nerves run back over the upper part of the surface exposed. II. Remove the preceding structures and expose — ■• 1. The conjoined aponeuroses of the Latissimus dorsi and Multindus spins muscles. No. 16. 1 2. The fascia lata over the Gluteus maximus muscle. III. Remove the preceding and expose the Erector and Multindus spina muscles, and the Gluteus maximus muscle. IV. Detach the preceding muscles, dividing branches of the Gluteal artery and vein to the Gluteus maximus muscle, 1 The dotted lines (1, 2, 3) indicate the skin incisions, and the others the piece of bone removed. 140 A MANUAL OF DISSECTIONS. and noticing branches of the Sacral plexus and Small Sciatic nerve entering its deep surface. There will now be exposed — On the Sacrum : 1. The upper three fourths of the posterior surface of this bone and the upper four foramina. 2. The superior and oblique Sacro-iliac and the Supra- spinous ligaments. 3. The posterior primary divisions of the upper four Sacral nerves. The inner branches will be divided on the removal of the Multifidus muscle ; the outer branches will be seen to unite in loops on the back of the Sacrum with one another, and a branch running up to the last Lumbar nerve will be seen. 4. The corresponding arteries and veins from and to the Lateral Sacral and Sacra Media vessels. Under the Gluteus maximus muscle will be seen — 5. The parts of the Sacrum and Ilium from which it arises, the spine of the Ischium, and the upper part of the great Trochanter covered by a bursa. 6. The Great and Small Sacro-sciatic ligaments. The following muscles from above downwards — 7. The posterior part of the Gluteus medius. . 8. The Piriformis. 9. The Gemelli with the intervening tendon of the Obtu- rator internus muscle. 10. The cut Superficial branch of the Gluteal artery and vein above the Pyriformis. 11. The Sciatic artery and vein below this muscle. 12. The Pudic artery and vein crossing the Ischial spine. 13. A second series of loops of the external branches of v. v. SACRAL PLEXUS FROM BEHIND. 141 the upper three Sacral nerves lying upon the Great Sacro-sciatic ligament. 14. The Great Sciatic nerve below the Pyriformis. 15. The Small Sciatic nerve, also below this muscle, branches to the Gluteus maximus muscle divided. 16. Branches of the Sacral plexus to the Gluteus maximus muscle, also divided. 17. The nerve to the Obturator internus muscle, usually outside, and the Pudic nerve, inside the Pudic artery. 18. The nerve to the Gemellus superior muscle. 19. The upper part of the nerve to the Gemellus inferior and Quadratus femoris muscles, if the Great Sciatic nerve is pulled outwards. a. Remove the Gluteus medius muscle from the pos- terior part of the Iliac attachment. b. Cut through the Pyriformis muscle as it emerges from the Pelvis, and turn it outwards. c. Cut through and remove the Sacro-sciatic liga- ments. d. Clear away fat and fascia from the posterior part of the Ischio-rectal fossa. e. Chisel through the Ilium from the centre of the great Sacro-sciatic foramen vertically upwards to the crest ; and through the Sacrum just out- side the posterior foramina, as far down as the fourth; connect these incisions above, and remove the included portions of the bones. The incision into the Sacrum should not be carried high enough to remove the upper part of the lateral mass, which is left. All but the upper part of the Sacro-iliac articulation is taken away and with it 142 A MANUAL OF DISSECTIONS. The oblique and transverse fasciculi of the Posterior Sacro-iliac ligaments. The Auricular cartilage. The Anterior Sacro-iliac ligaments. f. Remove the pieces of origin of the Pyriformis muscle, between the second, third, and fourth Sacral foramina. g. Take away the loose areolar tissue about the vessels and nerves. There will now be exposed — . 1. The Lumbo-sacral cord, 1 forming the Sacral 2. The first four Sacral Nerves, J Plexus. The following branches of the plexus will be seen — 3. The Gluteal from the Lumbo-sacral cord, and first, or first two Sacral nerves. 4. The Great Sciatic, a direct continuation of the plexus. , 5. The Small Sciatic branch arising by two cords from the lower part of the plexus, and traceable to the part formed by the first two Sacral nerves. 6. Nerves to the Gluteus maximus muscle from the same part of the plexus as the preceding, in front of it. 7. The Pudic branch derived from the third nerve, and involving the whole of the portion of the fourth which joins the plexus. 8. Usually two branches to the Pyriformis muscle arising from the upper part of the posterior surface of the plexus, or the first two nerves before they join it. 9. The nerve to the Obturator internus muscle will be seen below, but not at its origin from the union of the Lumbo-sacral cord and the first Sacral nerve on the anterior surface. The nerves to the Gemelli SACKAL PLEXUS FROM FRONT. 143 muscles will now be seen at their origin from the front and lower part. 10. The fourth Sacral nerve is seen perforating and running along the npper part of the Coccygeus muscle. 11. The Gluteal artery and vein seen between the Lumbo- sacral cord and the first. Sacral nerve. 12. The Sciatic artery and vein below the Sacral plexus. 13. The Pudic artery and vein. 14. Branches of the Lateral Sacral arteries accompany the Sacral nerves. 15. The Coccygeus muscle passes from the spine of the Ischium to the Sacrum and Coccyx. 16. A small piece of the Gluteus minimus muscle is seen at the margin of the Sacro-sciatic foramen. 17. A small piece of the Obturator internus muscle at the outer margin of this foramen. 18. The posterior part of the Levator ani muscle where the Ischio-rectal fossa is cleaned. 19. The Pelvic fascia is seen beneath the deep .surface of the plexus, separating the nerves from the branches of the Internal Iliac artery. A Dissection to Expose the Anterior Surface of the Sacral Plexus in the Male Sub- ject. The Leg being removed, the Buttock and Perineum dissected, the Abdomen opened, and the Viscera removed. Position. — The body lying on its back. I. The first step will be to make a side view of the Pelvis, and to do this the following steps are necessary on the 144 A MANUAL OF DISSECTIONS. side on which the section is to be made. The plexus of the opposite side is the one that is to be exposed. a. Remove the Psoas muscle and the External Iliac vessels along the brim, and part of the Iliacus muscle from the Venter Ilii. b. Dissect off the Pelvic fascia from the brim of the Pelvis. This is to be done carefully keeping close to the bone, and thus taking away the Obturator internus muscle, and the dissection should be carried nearly as far forwards as the Symphysis, backwards to the fascia of the Pyri- formis, and as low down as possible. c. Separate the Obturator fascia, with the falciform process of the Great Sciatic ligament, and the Obturator muscle, from the outer wall of the Ischio-rectal fossa. This incision will meet- the above. d. Saw off the spine of the Ischium. e. Saw through the Rami of the Pubis and Ischium, an . inch external to the Symphysis Pubis. f. Saw through the Innominate bone behind, the incision extending from the outer margin of the Quadratus lumborum above, vertically downwards to the great Sacro-sciatic foramen. Or the bone may be disarticulated behind, by removing the Multifidus and Erector spinae muscles from the Sacro-vertebral groove, dividing the Anterior and Posterior Sacro-iliac, the Ilio-lumbar, Lumbo-sacral, and Great Sciatic ligaments, and forcibly sepa- rating the bones. In this way the Auricular cartilage which adheres to the Sacrum mostly, may be displayed. g. When the bone is removed, the spine of the Ischium SACRAL PLEXUS FROM FRONT. 145 should be fixed down, and the Obturator interims muscle gently peeled off the outer surface of the Pelvic fascia, when the following will be exposed — 1. The Pelvic fascia, and white line extending from the lower part of the Symphysis to the Ischial spine. 2. The Obturator fascia below this line. 3. The Obturator nerve, artery, and vein, running transversely above, in this order from above downwards, and passing out in front through the opening above the Obturator membrane. They lie in the substance of the Pelvic fascia. The Pudic vessels, and nerve, are seen lying in the substance of the Obturator fascia, or rather in a sheath derived from its inner sur- face. They may be traced backwards round the Ischial spine, and as far forwards as the Triangular ligament. l II. Remove now the Obturator fascia at the white line. Divide the Anal fascia along this line ; cut through the origin of the Levator ani muscle from it, and expose the Recto-vesical fascia 2 running downwards and inwards to 1 A good dissection of the Pudic artery may be made in this way, but the anterior section of the bone would have to be modi- fied. 1 The above is the account of the arrangement of the Pelvic fascia as usually given. It is, however, frequently found, that the Pelvic fascia is directly continuous with the Eecto-vesical, and the white line is formed by the upper edge of the Obturator, which is looBely connected with the Pelvic by areolar tissue. The origin of the Levator ani muscle often extends considerably above the white line. 146 A MANUAL OF DISSECTIONS. the viscera. Below it are the following parts closing the Pelvic outlet from before backwards : — 1. The Triangular ligament. 2. The Levator ani muscle. 3. The Coccygeus muscle, and the smaller Sacro-sciatic ligament. 4. The Great and Small Sciatic nerves, the Pudic nerve, the nerve to the Obturator internus muscle. 5.. The Sciatic vessels, piercing the fascia of the Piri- formis. The preceding vessels and nerves leave the Pelvis be- low the Pyriformis muscle. 6. The Pyriformis muscle. 7. The Sacral plexus lying upon it, and giving off the above-named branches. 8. The Gluteal vessels and nerve, above the Pyriformis muscle, and piercing the fascia over it. III. a. Cut away the Recto-vesical fascia and its prolon- gations to the viscera on the side of the Pelvic section, the Pubo-prostatic ligament, and Ellis's ligament of the Rectum, ft. Remove the piece of Peritoneum passing to the viscera from the side of the Pelvis on which the section has been made, and display in this way a side view of the Pelvic viscera. 1 The following are the parts now seen — 1. The divided portions of the Innominate bone. 2. The Rectum in the concavity of the Sacrum and Coccyx ; most posteriorly branches of the Superior Haemorrhoidal artery may be seen in removing the 1 To show the parts more clearly, the Bladder should be inflated through the Ureter, and the Eectum filled with tow. SACRAL PLEXUS FROM FRONT. 147 sheath of Rectovesical fascia. Owing to the cur- vature of this viscus to the left, a better view is obtained by making the section on this side. 3. The Bladder in front of the preceding. 4. The Recto-vesical pouch, of Peritoneum between the Bladder and Rectum. 5. The Prostate gland surrounding the neck of the Bladder, and enveloped by the Prostatic plexus of veins, the sheath of the Recto-vesical fascia being removed. 6. In front of the preceding the two layers of the Triangular ligament perforated by the Membranous Urethra, and in front of the ligament the Bulb. 7. Between the Fundus of the Bladder and the Rectum the Vesicula Seminalis of the side dissected. 8. The Ureter is seen descending internally to the Internal Iliac vessels, and entering the posterior and external part of the Fundus of the Bladder. 9. The obliterated Hypogastric artery is seen running transversely on the upper part of the side of the Bladder to the apex, and continuous behind with the Internal Iliac artery. 10. Crossing over the immediately preceding structure, and running vertically down internally to it and the Ureter, is the Vas Deferens, accompanied by its artery. 11. Extending from the apex of the Bladder on to the Abdominal wall are the Urachus, and both oblite- rated Hypogastric arteries. 12. Extending from the Abdomen over the Sacro-iliac Synchondrosis the Internal Iliac artery. Its Ob- turator, Sciatic, and Pudic branches are divided, as well as the Gluteal, but the Superior, Middle, and 148 A MANUAL OF DISSECTIONS. Inferior Vesical offsets are seen, the former giving the branch to the Vas, and the Middle very incon- stant. The Middle Hemorrhoidal artery is also displayed, commonly arising from the Inferior Vesical or the Pndic branches. 13. The corresponding veins. These are plexiform at their origin, and form the Prostatic, Vesical, and Hemorrhoidal plexuses, which are found on the sides of the corresponding viscera. The Dorsal vein of the Penis is seen entering the Prostatic plexus. 14. The Pelvic plexus of the Sympathetic nerve of the side dissected is seen surrounding the Iliac vessels, and sending prolongations to the viscera along the vessels. 15. Lymphatic glands along the Iliac vessels. 16. Below these structures are seen the parts closing the outlet of the Pelvis already enumerated above. IV. Divide now the following structures — a. The Spermatic cord at the internal Abdominal ring of the side on which the section has been made. . b. The obliterated Hypogastric artery. c. The Ureter. d. The Vesical and Middle Haemorrhoidal arteries and veins of the side dissected. e. Cut through the Meso-rectum, containing the Superior Haemorrhoidal artery and vein, and the accompanying Sympathetic plexus, and draw the Rectum well over to the side from which the bone has been removed. /. Strip off the Peritoneum passing from the Blad- SACRAL PLEXUS FROM FRONT. 149 der and Rectum to the opposite side of the Pelvis. g. Divide the obliterated Hypogastric artery, the Sper- matic cord, the Vesical and Hemorrhoidal vessels, and the Ureter of the opposite side. h. Cut through the Recto-vesical fascia of the opposite side at its visceral attachments, and pull the Bladder over to the same side as the Eectum. i. Dissect out the Internal Iliac vessels and their branches, and remove them ; except the Obturator, whioh may remain on the Pelvic wall. These branches have already been enumerated. In cleaning these the other Pelvic Sympathetic plexus will be destroyed. J. Remove the fascia of the Pyriformis. There will now be exposed — 1. The anterior surfaces of the Sacrum and the Coccyx and the posterior surface of the Symphysis Pubis. 2. Lying on the Sacrum, the Sacra Media and Lateral Sacral arteries and veins. The Hypogastric Sympa- thetic plexus, and the gangliated cords of the Sympathetic, one on each side, are seen uniting below in the ganglion impar. The Coccygeal gland may be found below this, receiving branches from the ganglion impar and the Sacra Media artery. 3. The Psoas muscle, External Iliac vessels, and Pelvic wall of the opposite side, and covering the wall : — 4. The Pelvic fascia lining the Obturator internus muscle ; below is the white line, and below this the Kecto-vesical fascia covering the Levator ani muscle. The Recto-vesical , fascia may be seen closing the Pelvis in front, leaving in the median line a little triangular interval between the Pubic 150 A MANUAL OF DISSECTIONS. attachments of the Levatores ani ; here it is very thin, and dips down to join the Prostatic capsule. This fascia is seen to be separated from the Triangular ligament by the Levatores ani muscles. 5. The Obturator nerve, artery, and vein are seen run- ning across the Pelvic wall in this order from above downwards. Behind the Symphysis are the Pubic branches of the Obturator, and Deep Epigas- tric arteries. 6. The Coccygeus muscle behind the Levator ani muscle, passing from the sides of the Sacrum and Coccyx to the Ischial spine. 7 . The Sacral plexus consisting of the Lumbo-sacral cord, and the first, second, third, and part of the fourth nerves, their communications with the Sympathetic ganglia and the following branches. The Gluteal, arising from the posterior part of the Lumbo- sacral cord, and the first or first two Sacral nerves. The nerve to the Obturator internus muscle derived from the front of the plexus at the union of the Lumbo-sacral cord, with the first Sacral nerve. Visceral branches to the Bladder and Vagina, from the second, third, and fourth nerves (Godlee). Ellis describes them as coming from the fourth nerve, and sometimes from the third. In this dissection they came from the second, third, and fourth. 8. The remainder of the fourth nerve, its Haemorrhoidal branch, which is seen passing over the Coccygeus muscle and turning to the back of the Coccyx, between that muscle and the Levator ani, or per- forating the former. The branch to the visceral' surface of the Levator ani muscle, which also sup- THE PUDIC ARTERY. 151 plies the Coccygeus. This is internal to the pre- ceding, and is seen by dissecting off the Recto- vesical fascia from the Levator ani muscle. The nerve formed by the united anterior primary branches of the fourth, fifth, and the Coccygeal, perforating the Coccygeus muscle to be distributed to its posterior surface. A Dissection to Expose the Pudic Artery. Position. — The body in the lithotomy position, but the buttocks raised higher than usual by blocks beneath the Lumbar region. The side on which the dissection is to be made tilted higher than the opposite. The Scrotum should be hooked forwards on to the Abdomen. In this way, the side of the buttock, the Ischio-rectal fossa, and the Perinaeum may be seen in one view. I. Skin Incisions. 1. From the posterior superior Iliac spine vertically downwards to the tip of the Coccyx, then forwards encircling the anus and along the median raphe of the Perineum to the base of the Scrotum. 2. A transverse incision outwards for three inches from the upper and posterior end of No. 1. 3. A transverse incision outwards for two inches from the anterior end of No. 1. Reflect the flap outwards and expose the superficial fascia. Over the Perinjeum this consists of two layers, of which the superficial is now seen. The following structures in their order, from before backwards, are also displayed. 152 A MANUAL OF DISSECTIONS. 1. Cutaneous arteries from — a. The Superficial Perinaeal branch of the Pudic. b. The Inferior Hemorrhoidal over the Ischio- rectal fossa, and a branch turning round the edge of the Gluteus maximus muscle. No. 17. c. The Sciatic artery over the Gluteus maximus muscle, some offsets turning round the lower border, others perforating the muscle. The ending of the Coccygeal branch. d. The Gluteal passing through the Gluteus maximus muscle. At the back of the Ischio-rectal fossa, an offset of II. THE PUDIC ARTERY. 153 the Inferior Hemorrhoidal branch of the Pudic nerve, turning round the Gluteus muscle ; and 3. Branches of the Small Sciatic nerve external to it, and having a similar distribution. 4. The Hemorrhoidal branch of the fourth Sacral nerve in the angle between the Gluteus maximus and External Sphincter ani muscles. 5. The Coccygeal nerve close to the Coccyx. 6. The external branches of the posterior primary divi- sions of the upper three Sacral nerves, the smallest near the Iliac crest, the largest opposite the lower end of the Sacrum, the other by the side of the Coccyx. 7. Twigs passing backwards over the upper and posterior part of the space dissected, from the external branches of the posterior primary divisions of the upper three Lumbar nerves as they pass over the Iliac crest. a. Take away in front the superficial layer of the super- ficial fascia of the Perineum. b. Clean out the fat from the Ischio-rectal fossa, and remove the sheath of the Obturator fascia enclosing the Pudic vessels and nerve. c. Remove the fascia lata from the Gluteus maximus muscle behind. While these steps are being taken, the following structures will be seen : — In Front over the Perineum. 1. The Kami of the Pubes and Ischium. 2. The Superficial Perineal vessels running up to the Scrotum. 3. The Anterior and Posterior Superficial Perineal nerves, 154 A MANUAL OP DISSECTIONS. the latter external to the other. These nerves com- municate freely with one another. 4. More externally the Inferior Pudendal branch of the Small Sciatic nerve. It communicates with the Posterior, or External Superficial Perineal nerve. Bounding the Ischio-eectal Fossa the fol- lowing Structures will be found — 5. Internally. — The External Sphincter ani muscle, below it the Levator ani muscle covered by the Anal fascia, and the Coccygeus muscle. The latter posterior to the Levator ani. 6. Externally. — The Tuber Ischii and below it the Obtu- rator fascia covering in the Obturator' internus muscle, forming the outer wall. 7. Posteriorly. — The inferior border of the Gluteus maximus muscle. Contained in the Ischio-rectal Fossa the following Structures will be dissected — 8. In a sheath of the Obturator fascia, one and a half inches deep on the outer wall, the Pudic vessels. The Inferior Hsemorrhoidal branches are traceable transversely across the space to the lower end of the Rectum, and the Superficial Perineal vessels backwards to their origin from the Pudic. Cross- ing the front of the fossa is the small Transverse Perineal artery, which may be a branch of the main trunk, but more commonly arises from the Super- ficial Perinfflal branch. 9. The Pudic nerve will be found in the outer wall of the fossa deeper than the artery, but its Perinseal branch, which is considerably larger than the nerve THE PUDIC ARTERY. 155 itself, is superficial to the vessel. This branch will be found to be dividing in front into offsets, which may be better traced in a subsequent dissection. Opposite the Tuber Ischii the Inferior Hemorrhoidal branches of the main nerve pass inwards to the lower end of the Rectum, and communications with the Posterior Superficial Perineal and Inferior Puden- dal nerves may now be followed forwards. 10. The Hemorrhoidal branch of the fourth Sacral nerve may be seen passing between the Levator ani and Coccygeus muscles, or perforating the latter to be distributed to the External Sphincter muscle. On the Buttock — 11. The Gluteus maximus muscle will be cleaned, and the previously mentioned branches of the Sacral nerves will be found perforating it. III. a. Remove now in front the deep layer of the super- ficial fascia of the Perinseum, detaching it from the Pubic arch externally, and from the Trian- gular ligament behind. In doing this the distribution of the Perinaeal branch of the Pudic nerve may be with advantage traced. The fascia is seen to pass over the Transversus perinsei muscle to join the Triangular ligament. The nerve will be found to divide into the following branches : — 1. The Posterior Superficial Perinaeal, which passes on the cutaneous surface of the Transversus muscle. 2. The Anterior Superficial Perinaeal, running be- neath the Transversus muscle, and giving a 156 A MANUAL OF DISSECTIONS. transverse offset to the fore part of the Levator ani muscle. 3. Muscular branches, which may be traced to the Erector penis, Accelerator urinae, and Transversus perinsei muscles at once, and later on to the deep Transverse, and Con- strictor urethras muscles. 4. Slender twigs to the Corpus Spongiosum. The fascia investing the three superficial muscles may be now cleaned away. b. Remove the Gluteus maximus muscle from its attachments internally to the Sacrum and Coccyx, and cut it through externally in a line parallel with the reflected skin. There will now be exposed — In Front, the Anterior triangle of the Perineum, bounded Externally, by tbe Crus Penis with the Erector muscle lying upon it. Internally, by the Bulb of the Corpus Spongiosum Urethrse covered by the Accelerator urinse muscle. Posteriorly, by the Transversus perinsei muscle. The Floor, formed by the Anterior layer of the Trian- gular ligament of the Perinaeum. Under the Gluteus maximus muscle. 1. The Great Sacro-sciatic ligament passing between the sides of the Sacrum and Coccyx and the inner border of the Tuber Ischii. The Small Sacro-sciatic liga- ment crosses transversely beneath this from the side of the lower part of the Sacrum and the Coccyx to the Ischial spine. THE PUBIC ARTERY. 157 2. The upper and posterior part of the Gluteus medius muscle is the highest of the structures displayed. 3. The Pyriformis muscle is next below, emerging from the great Sacro-sciatic foramen. 4. Next, the tendon of the Obturator internus muscle passing out from the lesser Sacro-sciatic foramen. It is overlapped here by the Gemelli muscles, the origins only of which are seen. 5. The Superficial branch of the Gluteal artery is seen between the Gluteus medius and Pyriformis muscle with its accompanying vein, both however are divided at their point of entrance into the Gluteus maximus muscle. 6. The Sciatic vessels pass from the Pelvis below the Pyriformis muscle, and the Coccygeal branch is seen perforating the Great Sacro-sciatic ligament. 7. The Pudic vessels are seen upon the spine of the Is- chium, with the Pudic nerve inside and the nerve to the Obturator internus muscle outside them. 8. The Great and Small Sciatic nerves, the Pudic nerve, the nerve to the Obturator internus muscle, the nerve to the Gemellus superior muscle, and the nerve to the Gemellus inferior and Quadratus fe- moris muscles are exposed passing from the Pelvis below the Pyriformis. The latter two, however, are here beneath the Great Sciatic nerve. Branches to the Gluteus maximus muscle from the Small Sciatic and Sacral plexus are also seen. 9. On the surface of the Great Sacro-sciatic ligament, the second series of loops between the external branches of the posterior primary divisions of the upper three Sacral nerves is seen. 10. A bursa over the Tuber Ischii is opened. 158 A MANUAL OF DISSECTIONS. IV. a. Cut through in front the Superficial Perineal nerveB and turn them forwards. b. Detach the Cms Penis and Erector muscle from the Ramus of the Ischium and turn it inwards. This must be done carefully, to avoid injuring the Pudic artery, which lies between the Crus and the bone, but a branch, which enters the Corpus Cavernosum at this point is unavoidably divided. The Pudic nerve is found here with the artery, and a similar branch from it to the Corpus Cavernosum is cut through. c. Remove the Superficial Transversus perinsei muscle. d. Take away the Great Sacro-sciatic ligament, with the Coccygeal branch of the Sciatic artery, and the Sacral nerves. e. Cut through the Pyriformis muscle at its point of emergence and turn it outwards. f. Remove with the chisel the bone forming the inner portion of the upper part of the great Sacro-sciatic foramen, and the lower part of the Sacro-iliac articular surfaces, with the cartilage and ligaments in part. This is done to display the origin of the Pudic artery from the Internal Iliac trunk. There will now be exposed — In the Perineal Region. 1. The Anterior layer of the Triangular ligament. 2. The Pudic artery and nerve piercing it, and divid- ing into the branches for the Corpus Caverno- sum, which are now cut, and the branches for the Dorsum of the Penis, which pass forwards to THE PUDIC ARTERY. 159 pierce the Suspensory ligament, the nerve lying outside. The Anterior layer of the Triangular ligament may now be cleaned away, and the Pudic artery and nerve traced between the two layers. It will be found to give off a small transverse artery to the Bulb of the Corpus Spongio- sum, which reaches that structure by perforating the Anterior layer of the ligament. There will now be ex- posed — 3. The Deep Transversus perinsei muscle. 4. The Constrictor urethra muscle in front of the pre- ceding, but usually continuous with it. The branches of nerve from the Perinseal branch of the Pudic may now be traced to the preceding muscles. In the Ischiorectal region — The Pudic artery may be traced in the outer wall of the fossa. In the Gluteal region — The Pudic artery may be followed from the Internal Iliac trunk in front of the lower end of the Sacral plexus, over the spine of the Ischium to the Ischio-rectal fossa. The Sciatic and Pudic veins must be removed to do this. By the removal of the Pyriformis muscle, the following structures, in addition to those mentioned under Stage III., will be exposed — 1. Further portions of the Gluteal, and Sciatic arteries. 2. The first, second, third, and fourth Sacral nerves forming the plexus. 3. The first portion of the Gluteal nerve. 4. The nerves to the Pyriformis muscle from the upper and posterior part of the plexus. 160 A MANUAL OE DISSECTIONS. 5. The origin of the Pudic nerve, mainly from the third and fourth Sacral nerves. 6. The origin of the Small Sciatic nerve by two roots from the lower part of the plexus. Note 1 on the Tbiangulab Ligament op the Ubethea. The anatomy of the Triangular ligament of the Urethra has in the experience of the writer often proved to be somewhat of a stumbling block to students. This note is written with the view of endeavouring to make the connections of this structure clearer. The difficulty arises, I believe, from two causes : firstly, that identical parts of the Pelvic fascia have received a different nomen- clature ; and, secondly, that incorrect or at all events inexplicit accounts are given in most of the text books in ordinary use. To obviate the first difficulty, I shall take that account of the Pelvic fascia which is now commonly received, and indeed followed by the authors usually read ; but the connections of the various parts of which with the structure under consideration are either not stated ex- plicitly, or are else erroneously given. I mean that description which states that the Pelvic fascia divides at some point in a line extending from the Symphysis of the Pubes to the spine of the Ischium, into two parts, one of which extends in to the various Pelvic viscera, and the other of which is continued down on the inner surface of the Obturator internus muscle to the outlet of the Pelvis. The line of bifurcation is called the white line, the part of 1 Beprinted from the "Guy's Hospital Eeports." TRIANGULAR LIGAMENT OF THE URETHRA. 161 the fascia above this line is named Pelvic, the portion below, Obturator, and the piece extending in to the viscera Becto-vesical. Further, there is a thin fascia derived from the Obturator, which lines the under surface of the Levator ani muscle, to which the name Anal is applied. But whilst laying down these hard and fast lines, I will quote here a passage from " Quain's Anatomy " (vol. i., page 327), because whilst I have been repeatedly convinced of its accuracy, I do not think that any other of the authors ordinarily read, mention the facts stated therein. It is as follows : — " The Obturator fascia is sometimes included in the description of the Pelvic fascia, while the Recto-vesical is considered as an offset from it. It will be found how- ever on dissection, that the Recto-vesical fascia is always most directly continuous with the Pelvic fascia, and that the Obturator fascia is only loosely connected with it. Indeed the fibres of the Levator ani muscle in most cases pass upwards to some extent beyond the white line, and thus separate the Obturator from the Pelvic fascia." "We will now take the various descriptions 1 given of the anatomy of the Triangular ligament. We shall find that there is no difficulty about the Anterior or Superficial lamella, for this is described by all as a special layer of fascia closing the upper part of the Pubic arch. It is in the connections of the Deep layer, that the discordant accounts, real or apparent, are given. Thus in " Gray's Anatomy " (page 751) it is stated " the Posterior layer is derived from the Pelvic fascia," and again (pp. 755-56) the Pelvic fascia " is continuous below the Pubes with 1 The italics are my own, in all the succeeding quotations. M 162 A MANUAL OF DISSECTIONS. the fascia of the opposite side, so as to close the front part of the outlet of the Pelvis, blending with the Pos- terior layer of the Triangular ligament ; " and, further, the Obturator fascia "is a direct continuation of the Pelvic fascia below the white line, and is attached to the Pubic arch." The inference from this account is, I take it, that the Posterior layer is formed by the Pelvic fascia, closing the Pelvis in front and beneath the Symphysis, and that the Obturator division takes no part in the formation of the Triangular ligament, but stops short at the Pubic arch. In "Quain's Anatomy " (vol. i., page 326), we find "this layer (i.e. Deep layer of Triangular ligament) is super- ficial to the anterior fibres of the Levator ani, which lie between it and the Pelvic fascia, 1 and is connected with a thin web of areolar tissue which extends backwards on the surface of the Levator ani muscle, and is distinguished as the Anal fascia" The Obturator division is described as being attached to the Rami of the Pubes and Ischium. There is nothing said as to the connection of the Triangular ligament with the Pelvic fascia, or with any part of it, and I think that we must either infer that both layers of the ligament are to be looked upon as special fascia, or that else the Deep layer is derived from the Anal fascia. In Heath's account of the Triangular ligament, no mention is made of its connection with any part of the Pelvic fascia, but in describing the Recto-vesical layer (page 261), the following is stated, "it is seen to dip down to the Prostate, and is thus continued from one 1 The word Pelvic must here be read in connection with the passage quoted above (vol. i., page 327). Becto-vesieal is probably meant as being a direct continuation of the. Pelvic fascia. TRIANGULAR LIGAMENT OF THE UKETHRA. 163 side to the other of the Pelvis, of which it closes the outlet." In "Ellis's Anatomy" (eighth edition, page 546), no distinction is made between Pelvic and Obturator fasciae, but the whole membrane lining the inner surface of the Obturator muscle is called Pelvic, and the following state- ment is made : — "Inferiorly the fascia is attached to the hip bone along the side of the Pubic arch." He is here speaking of the part below the white line, i.e., the Obtu- rator division of other writers. On page 549, it is stated that the Recto-vesical fascia between the Pubo-prostatic ligaments of opposite sides "dips down to reach the Triangular ligament of the Perinaeum, and closes the Pelvis between the Levatores ani." On page 429 we find, "The Posterior layer (of the Triangular ligament) is derived from the Recto-vesical fascia ." Here, then, we have another account of the origin of this layer. I may here note that in the sixth edition of this writer's work (page 587), the account given of the Pelvic fascia differs substantially from the later one just quoted ; in that, it (the Pelvic fascia) is stated to be "continued from the one hip bone to the other, so as to close the cavity of the Pelvis in front for a short distance," and that, on page 458, it is said that " the Posterior layer {i.e., of the Triangular ligament) is derived from the Pelvic fascia ; " we must, however, of course, take the later description, which gives the origin from the Recto-vesical fascia. I think I have quoted enough to justify the state- ment that the connections of the Posterior layer of the Triangular ligament may well be a stumbling block, for we have the following different accounts given : — 1. Prom the Pelvic fascia (Gray). 2. A special structure, or from the Anal fascia (Quain). 164 A MANUAL OP DISSECTIONS. 3. From the Recto-vesical fascia (Ellis). It seems to me that the following considerations may- make the matter clearer. 1. The Pubic arch is of course below the level of the Symphysis. B No. 18. Diagram or the Posterior Surface of the Symphysis Pubis, showing the divisions of the Pelvic fascia and the connections of the Posterior layer of the Triangular ligament. P. Prostate. B. Bladder, drawn backwards. p. p. Pubo-prostatic ligaments. L. L. Anterior fibres of Levatores ani, arising from the lower part of the Symphysis. T. T. The Posterior layer of the Triangular ligament. The white line corresponds to the cut edge of the Becto-vesical fascia. The Pubo-prostatic ligaments to the anterior edges of the same ; between these there is an interval in which the Recto-vesical fascia dips down in the median line to join the Posterior layer of the Triangular ligament and the Capsule of the Prostate. The Pubo-prostatic ligaments are above the Levatores ani muscles. TRIANGULAR LIGAMENT OF THE URETHRA. 165 2. The white line extends from the lower part of the Symphysis Pubis. Therefore the Triangular ligament must be below the level of the Pelvic fascia, which only extends as far down as the white line. I believe the true account, and it is one which I have verified by dissection, to be as follows : — The Superficial layer is a special fascia. All accounts here agree. The Deep layer is formed by the Obturator fascia, which anteriorly is found to stretch across the Pubic arch and close it ; or perhaps a little more exactly, the Obturator fascia may be described as running down to be fixed to the margin of the Pubic arch, and a little above its attachment to give off a process which passes across the upper part of the arch, and which, joining with a like process from the fascia of the opposite side, forms the Deep layer of the Triangular ligament. If, therefore, in Gray's account for Pelvic we write Obturator, it would be correct. The Triangular ligament is continuous be- hind with the Anal fascia, but I do not think that the second alternative of Quain's description is correct, viz., that the Posterior layer is derived from the Anal fascia, for this would be tracing a comparatively thick mem- brane from a very thin one, and as to the first, that it is a special structure not connected with any division of the Pelvic fascia, I would say that I have often made out the continuity with the Obturator piece. Finally, we have Ellis's derivation from the Recto- vesical layer. This to my mind cannot be the case, for, as is indeed expressly stated by Quain, the fibres of origin of the Levator ani muscle from the Symphysis Pubis, are found distinctly, between the Recto-vesical fascia and the Posterior layer of the Triangular ligament. 166 A MANUAL OF DISSECTIONS. It is, however, a fact that the Rectovesical fascia closes the Pelvis above these attachments of the Levatores ani, " between the Pubo-prostatic ligaments of opposite sides," except in the centre, where it dips down to join the Prostate, leaving a small interval ; but this makes another layer closing the Pelvis just below the Symphysis, and we have indeed from without inwards — No. 19. a.ntebo-postero vertical section through the bladder and Symphysis Pubis. B. Bladder. P. Prostate. M. Membranous Urethra. p. p. Pubo-prostatic ligament. L. L. Levator ani, arising from the Symphysis, and placed be- tween the Pubo-prostatie ligament (i. e., Becto-vesical fascia) and the Posterior layer of the Triangular ligament. p. t. Posterior layer, and a. t. Anterior layer of the Triangular ligament. 1. The Superficial layer of the Triangular ligament. 2. The Deep layer of the same, derived from the Obturator fasciae. 3. The Becto-vesical fascia. And between the Eecto-vesical fascia and the THE PROFUNDA FEMORIS. 167 Triangular ligament, a median septum is formed by the former dipping down in the centre to join the latter. On either side of this there is a little space bounded above by the Recto-vesical fascia, below by the Deep layer of the Triangular ligament, and internally by the median septum, externally by the Pubic bone, and in this the anterior fibres of the Levator ani muscle run up to the Symphysis. The above statement is pretty nearly a reprint of my note in the " Guy's Gazette." ' Since it was written I have consulted Henle, and I gather that allowing for his difference of description, the connections are much the same as given above. " Handbook of Anatomy," vol. ii., part 1, pp. 406-8, p. 525, and fig. 402, and pp. 541-42. I find also that Godlee in the text to Part VI. of his Plates makes the following statements (page 220) : — "It (Obturator fascia) is to some extent continuous, along the arch of the Pubes, with the Posterior layer of the Triangular ligament." And again (page 221) : — " The Posterior layer of the Triangular ligament * * * at its attachment to the Pubic arch may be said to be con- tinuous with the Obturator fascia." A Dissection to Expose the Profunda Femoris Artery. Position. — The subject lying upon its back, the thigh abducted, and rotated out, the knee flexed, so that the foot of the side to be dissected rests upon the opposite thigh. I. Skin Incisions. 1. From immediately below the centre of Poupart's 168 A MANUAL OF DISSECTIONS. ligament along the upper two thirds of a line leading to the internal Condyle of the Femur. 2. An oblique incision at the upper end of No. 1, reaching for one and a half inches on either side, parallel with Poupart's ligament. 3. A transverse cut at the lower end of No. 1, for one and a half inches on either side. Reflect the flaps inwards and outwards, and expose the superficial fascia. This will be found at the upper part of the thigh to consist of two layers, which are most easily separable on the inner side of the Saphenous vein. Dissect out in it — 1. The Superficial External Pudic artery, at the upper and inner part. 2. The Superficial Epigastric artery, passing upwards over the centre of Poupart's ligament. 3. The Superficial Circumflex Iliac artery at the upper and outer part. 4. Small arteries derived from the Femoral trunk will be seen, with the several cutaneous nerves to be mentioned below. 5. The Long Saphenous vein receiving branches corre- sponding to the three above-named arteries, and at the upper part a large branch which collects the blood from the inner and back parts of the thigh ; sometimes there is a corresponding branch on the outer side. 6. Cutaneous twigs of the Internal Cutaneous nerve, one perforating near the Saphenous opening, and one or more lower down the thigh. 7. The Middle cutaneous nerve perforating the deep fascia at about the centre of the thigh, about three THE PROFUNDA FEMOEIS. 169 inches below Poupart's ligament. There are two branches, of which the outer is only seen to a small extent. 8. The Crural branch of the Genito-crural nerve cuta- neous, near the middle line, about one inch below Poupart's ligament. It is seen to communicate below with the Middle Cutaneous nerve. 9. Numerous lymphatic vessels in front of the thigh running upwards to lymphatic glands, which are found arranged in a row along the Long Saphenous vein. II. Remove the preceding structures, and expose the deep fascia. At the upper and inner part of the thigh, immediately below Poupart's ligament, the Saphenous opening will be dis- played : and the deep layer of the superficial fascia (Cribri- form fascia) which is attached to its margins being removed, a portion of the Femoral sheath will appear at its outer part. III. a. Clear away the deep fascia. In doing this the at- tachment of the superior Cornu of the Saphenous opening to Poupart's ligament must be divided. The cutaneous nerves should be preserved. b. Remove fat, fascia and lymphatics, from Scarpa's triangle. There will now be exposed — 1. The lower portions of the Sartorius and Adductor longus muscles. 2. The Psoas and a portion of the Iliacus muscles at the upper and outer part, most external of those form- ing the floor of Scarpa's triangle ; the Iliacus being outermost. 170 A MANUAL OF DISSECTIONS. 3. The lower part of the Pectineus muscle. 4. A small piece of the Adductor brevis muscle, between the Pectineus and the Adductor longus muscles. 5. A portion of the Vastus internus muscle below. 6. The Crural sheath covering in about the upper two inches of the Femoral vessels, and the ordinary areolar sheath below it. This, however, will most probably be taken away in cleaning the triangle, if not, it should now be removed. It will then be seen that the sheath is divided into three compart- ments by two fascial septa, the outermost one of which contains the Femoral artery, the middle the Femoral vein, and the innermost, which is only half an inch in length, contains a lymphatic gland. 7 . The Femoral artery is seen giving off the Superficial Pudic, Epigastric, and Circumflex Iliac arteries, at the upper part, and lower down the Inferior Exter- nal Pudic twig, which crosses inwards over the Pectineus muscle. The Profunda branch arises from one to two inches below Poupart's ligament on the outer side, but is exceedingly variable in its place of origin, and may come off at any point be- tween Poupart's ligament and fonr inches below it. The Internal and External Circumflex branches of the Profunda artery may be seen at their origins, the former passing backwards between the Psoas and Pectineus muscles, the latter running out be- tween the Superficial and Deep divisions of the Anterior Crural nerve. These last two branches, however, are also very variable in origin, and are often found arising from the Common Femoral trunk. Muscular branches of the Femoral artery are also displayed. THE PROFUNDA FEMORIS. 171 8. The Femoral vein is seen receiving branches similar to those of the main artery, except that the twigs cor- responding to the Superficial Pudie, Epigastric, and Circumflex Iliac arteries run into the Long Saphe- nous vein, which also is seen to join the Femoral vein quite at its upper part. The Femoral vein at Poupart's ligament lies internal to the artery, but at the apex of Scarpa's triangle is beneath it ; the Profunda vein is superficial to its artery, so that in Scarpa's triangle these two large veins lie be- tween the Superficial and Deep Femoral arte- ries. 9. The Anterior Crural nerve is displayed lying between the Psoas and Iliacus muscles, about half an inch to the outer side of the Femoral artery. The Middle and Internal Cutaneous, and the Internal Saphenous offsets are traceable from it. Parallel with the last nerve, but external to it, a large nerve to the Vastus internus muscle may be seen. The Middle Cutaneous branch is found supplying the Sartorius muscle, and the two small nerves to the Pectineus muscle, which pass beneath the Femoral artery, may be followed. The distribution of the other muscular branches to the Rectus and "Vastus externus muscles cannot be traced, but they are seen at their origins. 10. By separating slightly the Pectineus from the Ad- ductor longus muscles, the Superficial division "of the Obturator nerve is seen lying upon the small portion of the Adductor brevis muscle which is exposed. A slender twig of this nerve which runs along the inner border of the Adductor longus muscle may now be found. It is distributed to J 72 A MANUAL OF DISSECTIONS. •the Obturator plexus, but the ending cannot now be traced. IV. Divide now the Sartorius muscle at the lower part of the dissection, and turn it outwards and inwards. Beneath it is found the aponeurotic covering of Hunter's canal, which should be taken away. In addition there will now.be seen — 1. Further portions of the Femoral artery and vein, the latter passing to the outer side of the artery. The Anastomotica Magna branch of the artery, coming off at the lower part of the canal. 2. More of the Long Saphenous nerve. It may lie on the outer side of the artery throughout the extent of the canal, or it may cross from the outer to the inner side, over it. 3. The branch of the Obturator nerve to the plexus of the same name may now be traced to its communi- cation with the Inner branch of the Internal Cuta- neous nerve. 4. Both Anterior and Inner branches of the Internal Cutaneous nerve will be seen, the former lying upon the artery, the latter to its inner side. A communication between the Inner branch and the Saphenous nerve is traceable, thus completing the so-called Obturator plexus. V. a. Hook outwards the Anterior Crural nerve dividing the Internal Cutaneous and Long Saphenous branches. b. Cut through the Femoral artery at its lowest part, and hook the ends upwards and downwards, dividing at the same time its muscular offsets. c Remove the Femoral and Profunda veins. THE GLUTEUS MINIMUS. 173 d. Divide the tendinous insertion of the Adductor longus muscle, and pull the muscle inwards. There will now be exposed — 1. The lower part of the Adductor magnus muscle, at its attachment to the Femur. 2. The whole length of the Profunda Femoris artery, and the origin of its branches, viz., the Internal and External Circumflex, and the four Perforating ; the npper two of which pierce the Adductor brevis muscle, the third and fourth (which last is the termination of the artery) passing to the back of the thigh through the Adductor magnus muscle. VI. The Adductor magnus muscle must be divided at its Femoral attachment, behind the opening for the Femoral artery, to follow out the terminal or fourth Perforating twig. A Dissection to Expose the Gluteus Minimus Muscle. Position. — The body lying on its face, the Abdomen and the Pelvis raised on blocks, and the legs hanging down to a moderate degree. I. Skin Incisions. 1. From the anterior-superior Il'iac spine to the ante- rior-inferior angle of the great Trochanter. 2. From the upper end of No. 1, along the anterior two thirds of the Iliac crest, and then downwards and backwards to a point three inches below the posterior-superior Iliac spine. 174 A MANUAL OF DISSECTIONS. Reflect the flap downwards, and expose the loose fascia of the buttock, containing — 1. The posterior branches of the External Cutaneous nerve most anteriorly. 2. The Lateral Cutaneous branch 1 of the last Dorsal nerve, crossing the Iliac crest, and running as far as the Trochanter major. No. 20. ■^ 3. The Iliac branch of the Ilio-hypogastric nerve ' pos- terior to this. 4. The external branches of the posterior primary divisions of the first three Lumbar nerves, crossing the Iliac crest still further inwards. 5. The external branches of the posterior primary divi- sions of the first two Sacral nerves, — the upper one near the Iliac crest, the lower giving filaments over the lower part of the surface exposed. 1 These nerves bear an inverse ratio to one another as to their size. THE GLUTEUS MINIMUS. 175 II. Remove the preceding structures and expose — The fascia lata forming externally the Ilio-tibial band, above covering the Gluteus medius nrascle, and dividing to enclose the Gluteus maximus muscle. III. Remove the fascia covering the Gluteus maximus, and reflect this muscle inwards, by dividing the upper part of its fascial insertion and the fleshy fibres, in a line corresponding to the lower margin of the reflected skin. In doing this — a. The Superficial branch of the Gluteal artery will be divided. b. The Inferior Gluteal branches of the Small Sciatic nerve will be cut, with arteries from the Sciatic. c. Branches to the reflected muscle from the part of the Sacral plexus formed by the first and second nerves will be seen. c. The bursae over the great Trochanter, and the Vastus externus muscle will be opened. Divide the Tensor vaginse femoris muscle at its origin, and hook it well forwards, cutting the branches supplying it from the Gluteal artery and nerve. There will now be exposed, from above downwards : — 1. The Gluteus medius muscle. 2. The Pyriformis muscle. 3. The Gemellus superior muscle. 4. The Obturator internus muscle. 5. The Gemellus inferior muscle, at its insertion. 6. The Vastus externus muscle on the outer side. 7. The Trochanter major, below and externally. 8. Beneath the Tensor vaginas muscle is an anastomosis 176 A MANUAL OF DISSECTIONS. between the Gluteal, External Circumflex, and Circumflex Iliac arteries. 9. The divided Superficial branch of the Gluteal artery and vein above the Piriformis muscle. 10. The Sciatic artery and vein emerging below the Pyriformis muscle. 11. The Pudic artery, vein, and nerve, leaving the Pelvis at the same spot ; the artery giving a branch to the Digital fossa. 12. The Great and Small Sciatic nerves are seen below the muscle. 13. The nerve to the Obturator internus muscle is seen crossing the spine of Ischium, usually having the Pudic artery to its inner side and the Pudic nerve still more internal. 14. The small nerve to the Gemellus superior muscle may be seen by pulling outwards the Great Sciatic nerve. IV. Cut through at their origins and insertions^ the Gluteus medius, and Pyriformis muscles, and remove them. Branches of the Gluteal artery and nerve will be divided in taking away the former muscle. 1. The Gluteus minimus muscle will now be fully ex- posed, and lying upon it the Gluteal nerve and Deep branch of the artery of the same name. Each divides into an upper and lower branch, the former of which runs along the upper margin of the muscle, the latter crosses it, passing downwards and out- wards ; the nerve to supply the Tensor vagina femoris muscle, and the artery to join in the anas- tomosis previously mentioned. The Great Sciatic nerve may be required to be pulled inwards a little from off the muscle. THE POPLITEUS. 177 2. All the structures previously mentioned as leaving the Pelvis below the Piriformis muscle will be more fully seen, and in addition 3. The Pelvic fascia on the deep surface of the Piri- formis muscle. A Dissection to Expose the Popliteus Muscle. Position. — The leg lying on its anterior surface. I. Skin Incisions. 1. From the middle of the outer surface of the exter- nal Condyle of the Femur obliquely downwards and inwards across the back of the joint to the upper margin of the inner Tuberosity of the Tibia at its centre. 2. From the outer end of (1) vertically downwards for one inch. 3. From the inner end of (1) vertically downwards for the upper third of the leg. Reflect the flap downwards, and expose the superficial fascia, containing — 1. Branches of the Internal Saphenous nerve running backwards over the Tibia at its inner part. 2. The Inner branch of the Internal Cutaneous nerve posterior to this. 3. Branches of the Small Sciatic nerve perforating the fascia over the Popliteal space, and the nerve itself coming through just below it. 4 Branches of the External Popliteal nerve supplying the skin at the outer part. N 178 A MANUAL OP DISSECTIONS. 5. On the inner side a cutaneous artery from the Anas- tomotica Magna. 6. The termination of the Sciatic artery with the Small Sciatic nerve, but here reinforced by a branch from the Popliteal. 7. A cutaneous artery on the outer side from the Popli- teal, which accompanies the External Popliteal nerve. No. 21. 8. The Internal Saphenous rein along the inner border of the Tibia. 9. The External Saphenous vein along the centre of the space, and usually perforating the fascia lata opposite the centre of the articulation, but some- times running up higher. 10. Lymphatics. II. Kemove the preceding structures including the In- ternal Saphenous vein. This exposes the fascia lata,. THE POPLITEUS. 179 strengthened over the Popliteal space by transverse fibres. This must be taken away, and then the following are exposed — 1. Above and externally, the tendon of the Biceps muscle inserted into the head of the Fibula and split by the Long External Lateral ligament. 2. Below, externally and internally, portions of the heads of the Gastrocnemius muscle, the greater part of the inner being visible. 3. A part of the origin of the Plantaris muscle, above the outer head of the Gastrocnemius muscle. 4. On the inner side and below, the tendons of the Semi- membranosus and the Semitendinosus muscles, the prolongation of the latter to the fascia lata is divided. 5. Along the median line, the Internal Popliteal nerve giving off branches below, to both heads of the Gastrocnemius, to the Plantaris, Soleus, and Popli- teus muscles, the commencement of the Inferior Internal Articular nerve, and a cutaneous branch running downwards to the integument of the calf, and called the ramus Communicans Tibialis, 1 or sometimes the External Saphenous nerve. 6. The External Popliteal nerve following the tendon of the Biceps muscle. A slender branch of this, or of the Great Sciatic nerve, which comes off above the limits of the dissection, may be seen lying on its outer side ; it gives off, above, the Superior External Articular, and below, the Inferior External Articular branches, the latter of which passes beneath the 1 For simplicity's sake these branches should be called the Com- municans Tibialis and Communicans Fibularis, and the nerve which results from their junction the External Saphenous. 180 A MANUAL OF DISSECTIONS. outer head of the Gastrocnemius muscle. The Ex-, ternal Popliteal nerve gives off the ramus Oom- municans Peronei 1 or Fibularis, which perforates the fascia lata considerably above the ramus Communicans Tibialis. 7. The Popliteal vein below and internal to the Internal nerve, receiving the External Saphenous branch, and other veins corresponding to the offsets of the artery to be next enumerated. 8. The Popliteal artery below and internal to the vein, and almost hidden by it and the Internal nerve. Branches running up to the Ham-string muscles and others descending to the calf are seen (Sural), the Superior External Articular artery with the corre- sponding nerve, the Inferior Internal and External Articular offsets, with the nerves of the same name, and the Azygos branch. There is also a cutaneous branch previously seen accompanying the External Popliteal nerve. 9. Four or five lymphatic glands or fewer along the Popliteal vessels. III. a. Hook the Semitendinosus, and Semimembranosus muscles internally. b. Divide the Gastrocnemius muscle above and below, and remove it within the limits of the skin in- cisions. Its nerves and arteries will be divided, and there will now be exposed — 1. The Popliteus muscle at the upper part of the Tibia, 1 For simplicity's sake these branches should be called the Com- municans Tibialis and Communicans Fibularis, and the nerve which results from their junction the External Saphenous. THE POPLITEUS. 181 covered by its special fascia derived from the tendon of the Semimembranosus muscle. 2. The Soleus muscle below it. 3. The Plantaris muscle crossing it, passing over the vessels and the Internal nerve. The Plantaris should be taken away, inasmuch as it crosses the next-mentioned structures. 4. More of the Internal Popliteal nerve and the branches more fully — viz., to the Soleus muscle, to the Popli- teus muscle. The nerve to this latter muscle is seen turning round the lower border. The Inferior Internal Articular branch running along the upper border of the Popliteus muscle, and beneath the expansion of the Semimembranosus muscle with the corresponding artery. 5. A further portion of the Popliteal artery, and its branches enumerated above, more fully. 6. More of the Popliteal vein. IV. a. Divide now and remove the Popliteal artery and vein, and the Internal Popliteal nerve.- b. Cut through the Biceps tendon. Open the Capsule of the joint by removing its outer part, and divide the Long and Short External Lateral ligaments. c. Remove the fascia over the Popliteus muscle, and trace out the tendinous origin of the muscle from the external Condyle. The whole of the Popliteus muscle will be now exposed, and in addition — 1. The ligament of Winslow. 2. More of the Inferior External Articular nerve, and vessels. 182 A MANUAL OF DISSECTIONS. A Dissection to Expose the Peroneal Artery and its Branches. Position. — The body supine, the leg rotated; outwards and lying upon its inner aspect. I. Skin Incisions. 1. From the head of the Fibula along the upper two thirds of the bone, to the centre of the anterior surface of the ankle-joint. No. 22. 2. A transverse incision from the upper end of No. 1 backwards, to a little beyond the middle of the posterior surface of the leg. 3. A third from the lower end of No. 1 downwards and forwards to the base of the fifth Metatarsal bone, then backwards along the inner border of the foot to the centre of the heel. Reflect the flap backwards, and expose the superficial fascia and the following parts — THE PERONEAL ARTERY. 183 1. The triangular subcutaneous surface and the external Malleolus of the Fibula. 2. The External Saphenous vein, from its commencement at the outer side of the Dorsum of the foot, upwards behind the outer ankle and along the median line of the leg through the whole extent of the dissec- tion. 3. Cutaneous arteries. a. From the Popliteal above and externally, with branches of the External Popliteal nerve. b. From the Sciatic along the median line, with the Small Sciatic nerve, reinforced by twigs from the Popliteal artery. c. Numerous branches from the Peroneal along the outer border of the Fibula, and others behind the external Malleolus. d. From the Anterior Tibial artery in front of the Fibula, with branches of the Musculo- cutaneous nerve ; and the External Malleolar arterial branch in front of the ankle. e. Twigs from the External Plantar and Tarsal arteries at the outer side of the Dorsum of the foot. 4. Cutaneous branches of the External Popliteal nerve at the upper and outer part ; one larger than the rest, called ramus Communicans Fibularis, running downwards and inwards to the middle of the calf. 5. The small portion of the Communicans Tibialis nerve seen superficial to the deep fascia, a little above the centre of the calf. 6. The nerve called External Saphenous resulting from 184 A MANUAL OF DISSECTIONS. the junction of the preceding, and accompanying the vein of the same name behind the external Malleolus to the outer border of the foot. 7. The Small Sciatic nerve perforating the fascia lata just below the Popliteal space, running down the middle of the leg, and joining the Communicantes Tibialis and Fibularis nerves just at their union. Branches of this nerve are cutaneous at the upper part. 8. In front of the Fibula branches of the Musculo- cutaneous nerve, which run to the fourth and fifth toes, and other filaments supplying the skin on the outer side of the Dorsum of the foot. II. Remove the preceding structures and expose the fascia lata, which will be seen forming the upper and lower divisions of the Anterior Annular ligament in front of the ankle, and the External Annular ligament between the Malleolus and Os Calcis. In front of the exposed portion of the Fibula the fascia is very strong, and joined to the outer border of the bone. III. Remove the above fascial structures and expose — 1. The Gastrocnemius muscle and tendo Achillis. 2. The outer border of the Soleus muscle, seen beneath the preceding. 3. The Peroneus longus muscle lying on the Fibula, and covering in the Peroneus brevis muscle except for the anterior part of the lower third. 4. The lower part of the Peroneus tertius muscle in front of the Fibula. 5. The upper part of the origin of the Extensor brevis digitorum muscle on the Dorsum of the foot. THE PERONEAL ARTERY. 185 6. The Anterior Peroneal artery and vein in front of the lower end of the Fibula, and on the outer side of the Dorsum of the foot. 7. The small portion of the lesser Sciatic nerve, which, in this dissection, lies beneath the fascia lata. 8. The greater part of the Communicans Tibialis nerve, which is beneath the deep fascia. 9. The External Popliteal nerve at the upper part of the head of the Fibula. IV. Divide the Gastrocnemius and Soleus muscles above as far as the centre, and pull them well inwards. In doing this, the nerve to the latter will be probably cut through. Remove the aponeurotic arch over the upper part of the Posterior Tibial vessels and nerve. There will now be exposed — 1. The Popliteus muscle covered by its fascia at the upper part, with its nerve lying on the posterior surface, and turning round the lower border. 2. The aponeurosis stretching over the Tibialis posticus muscle, between the bones of the leg, immediately below it. The fibres of the muscle are visible through the aponeurosis. 3. The Flexor longus pollicis muscle, lying on the lower two thirds of the inner surface of the Fibula. 4. The Popliteal artery and its bifurcation. The Anterior Tibial branch passing between the lower border of the Popliteus muscle and the Tibialis posticus muscle. The Posterior Tibial branch lying on the aponeurosis of the Tibialis posticus muscle, and giving off the Peroneal artery, which runs downwards and outwards for a short distance to enter the substance of the Flexor longus pollicis muscle. 186 A MANUAL OF DISSECTIONS. 5. The venae comites of the preceding, uniting to form the Popliteal vein. 6. The Posterior Tibial nerve at first to the inner side of the artery of the same name, but soon crossing it to the outer side. The branches to the Tibialis posticus and Flexor longus pollicis muscles are seen, the latter running with the Peroneal artery. V. a. Trace down the Peroneal artery in the substance of the Flexor longus pollicis muscle, divide the muscle below and pull its lower end downwards. The nutrient and muscular branches will be now seen. b. Divide the External Annular ligament if not done previously, and open up the sheath of the Pero- neus longus muscle at the outer border of the foot. c. Cut through the Peronei longus and brevis muscles, and turn the ends upwards and downwards. d. Saw through the Fibula at the junction of the lower with the upper three fourths, and again two inches lower down, above the external Malleolus. Remove this piece of bone by dividing the attached fibres of the Tibialis posticus and Peroneus tertius muscles and the Interosseous and Inferior Interosseous ligaments. The Peroneal artery may now be followed in its whole course. Below, it is seen lying on the posterior Tibio-fibular ligament, and receiving the communicating branch from the Posterior Tibial artery, which may come over or under the tendon of the Flexor longus pollicis muscle. The artery may be traced down behind the THE PLANTAR ARCH. 187 external Malleolus to its anastomoses, with twigs of the Tarsal and External Plantar arteries. The Anterior Peroneal branch may be followed round the front of the outer ankle to its anastomoses with the External Malleolar and Tarsal arteries. A Dissection to Expose the Plantar Arch. Position. — The foot must be arranged with the Plantar surface uppermost. In an entire body this will best be done by turning the subject on the face, flexing the knee, and supporting the leg with blocks. I. Skin Incisions. 1. Along the median line of the foot from the Os Calcis to the root of the third toe. 2. Transverse incisions from the anterior and posterior ends of this, to the inner and outer borders of the foot and heel respectively. Reflect the flaps inwards and outwards, and expose the superficial fascia. Clear it away, dissecting out at the same time — 1. The Superficial Transverse ligament, across the roots of the toes in the rudimentary web of the foot. 2. The Lumbricales muscles, with the Digital vessels and nerves in the intervals of the Plantar fascia. 3. The Plantar Cutaneous branches of the Posterior Tibial artery, vein, and nerve, in the hollow of the heel. 4. At short distances from the inner and outer borders of the foot along the furrows of the internal and external intermuscular septa, some small unnamed 188 A MANUAL OF DISSECTIONS. arteries and nerves derived from the Internal and External Plantar, respectively. 5. At the clefts of the toes, the Digital vessels and nerves will be found issuing from between the pro- cesses of the Plantar fascia and passing beneath the Superficial Transverse ligament ; those to the inner side of the first and the outer side of the fifth toes, however, perforate further back than the rest. The origin of these vessels and nerves is not now traceable. 6. When the superficial fascia or fat is completely re- moved, the preceding vessels. and nerves will be displayed, and the Plantar fascia. This will be found to be made up of three portions : a central, thick and triangular, with its apex at the heel, and its base cut into five processes, one for each toe ; and two lateral portions which are thin and unim- portant, except that there is a strong process on the outer side between the Os Calcis and the base of the fifth Metatarsal bone. II. Remove now the Plantar fascia, by a longitudinal in- cision along the median line, and a transverse one at the Os Calcis. Reflect it forwards ; in doing this two septal processes, one on each side of the Flexor brevis digitorum muscle, will be found. The Digital vessels and nerves and the Lumbricales muscles are to be preserved, the rest of the above-mentioned structures will be removed. There will now be displayed — 1. The Abductor pollicis muscle, along the inner border of the foot. 2. The Flexor brevis digitorum muscle, along the centre of the foot. It is found to be giving off four tendons, one to each of the four outer toes, these THE PLANTAR ARCH. 189 are seen entering their corresponding sheaths, which reach for a short distance into the foot. 3. The Lumbricales muscles are seen in the intervals of the tendons of the Flexor brevis digitorum muscle. The innermost one is on the Tibial side of the tendon to the first toe, the others are in the inter- vals of the tendons ; they pass to the Tibial side of the first Phalanges. 4. The Abductor minimi digiti muscle, along the outer border of the foot. 5. The tendon of the Flexor longus pollicis muscle in part, on the outer side of the Abductor pollicis muscle. 6. Small portions of the insertions of the Flexor brevis pollicis muscle, into the inner and outer sides of the base of the Metatarsal Phalanx of the great toe. 7. A small part of the Flexor brevis minimi digiti muscle at its insertion into the first Phalanx, lying on the inner side of the Abductor minimi digiti muscle. 8. The Internal Plantar artery and vein, in the anterior part of its course emerging from beneath the Ab- ductor pollicis. Different accounts of the ending of this artery are given. According to Gray and Quain, it terminates by running along the inner side of the great toe. Ellis's description is that it gives off four branches, the innermost of which runs to the inner side of the great toe, the outer three dip down in the first, second, and third interosseous spaces to join the Digital branches of the Deep Plantar arch. I believe that both accounts are true in different cases. 190' A MANUAL OF DISSECTIONS. 9. The External Plantar artery and vein, in a small part of their course. They are seen at the anterior and outer part of the foot, between the Abductor minimi digiti muscle and the outer border of the Flexor brevis digitorum muscle. The branch to the outer surface of the little toe is visible. 10. The Internal Plantar nerve, emerging with the cor- responding artery from beneath the Abductor pol- licis, and dividing in front into four Digital branches which lie upon the tendons of the Flexor brevis digitorum, one undivided for the inner side of the great toe, the others bifurcating at the clefts of the toes to supply the contiguous sides of the first and second, second and third, and third and fourth. In this dissection they are only seen as far as the bifurcation. By separating the Abductor pollicis from the Flexor brevis digitorum posteriorly, branches may be traced from the trunk of the Inter- nal Plantar nerve to these muscles. The innermost Digital offset will be found supplying the Flexor brevis pollicis muscle, the next two the two inner- most Lumbricales muscles, and the outermost com- municates with the inner of the two Digital branches from the Superficial division of the External Plantar nerve. 11. The Superficial branch of the External Plantar nerve, appearing between the Abductor minimi digiti and the Flexor brevis digitorum muscles, a little anterior to the base of the fifth Metatarsal bone. It is seen dividing into two Digital branches, one undivided for the outer side of the little toe, the other bifurcated for the contiguous sides of this toe and the next. THE PLANTAR ARCH. 191 inn. a. Cut through the Internal Plantar nerve behind, and throw it over the toes. The branches of the artery of the same name, to the second, third, and fourth interosseous spaces, must be divided if present. b. Divide the Flexor brevis digitorum muscle, and throw it towards the toes. Its nerve from the In- ternal Plantar will be torn through. There will now be exposed — 1. The tendon of the Flexor longus digitorum muscle. This is seen to be dividing into four slips, one for each of the four outer toes. They each enter the corresponding Digital sheath beneath the Flexor brevis tendon. The following are also seen con- nected with this muscle, viz. — a. The Accessorius muscle, passing from the Os Calcis to the hinder border of the tendon of the Flexor longus digitorum, but from which tendinous slips are traceable to those tendons of the long Flexor which run to the second, third, and fourth toes (Turner). A portion of the Inferior Calcaneo-cuboid or Long Plantar ligament is seen behind close to the Os Calcis, between its two heads of origin. 6. The Lumbricales muscles. The innermost arising from the Tibial side of the innermost tendon, the other three from the contiguous sides of the first and second, second and third, and third and fourth tendons. 2. The tendon of the Flexor longus pollicis muscle, lying beneath (in this position) the Flexor longus digi- torum muscle. A tendinous slip passes from the 192 A MANUAL OF DISSECTIONS. former to the latter at the hinder part of the foot, and is said to be traceable to the slips of the Mexor longus digitorum, running to the second and third toes (Turner). 3. A farther portion of the Flexor brevis pollicis muscle, running to each side of the base of the first Phalanx of the great toe, with the tendon of the Flexor longus pollicis lying between these two heads. 4. The Flexor brevis minimi digiti muscle, lying upon the Metatarsal bone of the little toe. 5. The Plantar and Dorsal Interossei muscles of the fourth space, the former lying externally. 6. The External Plantar artery, with its accompanying vein. The vessel is seen behind, emerging from beneath the Abductor pollicis muscle, and running obliquely forwards and outwards over the Acces- sorius muscle to a point opposite the base of the fifth Metatarsal bone. It then turns transversely inwards, and passes beneath the tendon of the Mexor longus digitorum muscle ; just as it makes this bend it gives off the branch to the outer side of the little toe, which has been previously seen. 7. The External Plantar nerve, taking the same course as the artery as far as the base of the fifth Meta- tarsal bone. At that point it is divided into a Superficial and a Deep branch. The former has been already seen dividing into two Digital branches for the little, and the opposed side of the fourth toe ; besides this, the outermost of the two is now seen to be supplying the Flexor brevis minimi digiti muscle, and often the Interossei mus- cles of the fourth space ; the inner has been found to communicate with the fourth Digital branch of IV. THE PLANTAR ARCH. 193 the Internal Plantar nerve. The Deep division passes, with the External Plantar artery, beneath the tendons of the Plexor longus digitorum. The trunk of the External Plantar nerve may be now found supplying branches to the Accessorius and Abductor minimi digiti muscles, in the posterior part of its course which was previously covered by the Plexor brevis digitorum. a. Divide the tendon of the Flexor longus digitorum and the Accessorius muscle transversely at their junction. This point is taken in order to leave the Accessorius muscle with the External Plantar vessels and nerve lying upon it. The tendons of the long Flexor muscle, with the at- tached Lumbricales, should now be reflected over the toes. As this is done two slender nerves to the two outermost Lumbricales will be found coming from the Deep branch of the Ex- ternal Plantar nerve. There will now be ex- posed — 1. The Flexor brevis pollicis muscle, most internally. 2. The Adductor pollicis muscle, external to this parallel with its outer border. 3. The Flexor brevis minimi digiti muscle, lying upon the fifth Metatarsal bone. 4. The Transversalis pedis muscle, lying transversely across the Metatarso-phalangeal articulations. 5. The Plantar and Dorsal Interossei muscles, of the third and fourth spaces, and just the anterior end of the Plantar of the second, lying in the triangular interval formed by the Adductor pollicis, Plexor brevis minimi digiti, and Transversalis pedis mus- O 194 A MANUAL OF DISSECTIONS. cles. The Adductor pollicis may, however, conceal the Interossei of the second space completely. 6. Further portions of the External Plantar vessels. The portion of the artery which extends beyond the base of the fifth Metatarsal bone is called the Plantar arch. The Digital branches of the arch which run forwards in the fourth and third spaces, and the anterior part of the one in the second space, will be seen. They pass in front beneath the Transversalis pedis muscle. The Posterior Perfo- rating offsets of the two outer Digital branches, which pass through the heads of the Dorsal In- terossei to the Interosseous arteries of the Dorsum may be traced, but only the anterior part of the Digital branch of the second space will be seen,- as . the posterior part is concealed by the Adductor pollicis muscle. Each of these Digital branches is seen to bifurcate at the cleft "of the toes, and from the point of bifurcation other slender offsets (Anterior Perforating) also to the Dorsal Interos- seous arteries, are traceable. 7. The Deep branch of the External Plantar* nerve may be followed to its ending in the Adductor pollicis muscle. Branches are traceable to the Transver- salis pedis, and at this stage only to the Interossei of the third space, and the fourth .when not sup- plied by the Superficial division. The offsets to the two outer Lumbricales have been already seen. V. a. Remove now the Adductor pollicis muscle and the outer portion of the Flexor brevis pollicis muscle. The nerves to the former from the Deep division of the External Plantar will be divided. THE PLANTAR ARCH. 195 There will now be exposed — 1. The Interossei muscles of the first and second spaces. 2. The remaining portion of the Plantar arch and its junction at the back of the first interosseous space, with the communicating branch from the Dorsalis Pedis artery. The Digital branch of the second space is now displayed, and its Posterior Perforating offset is now traceable. 3. The arteria Magna Pollicis is seen arising from the Dorsalis Pedis artery, where it dips into the sole of the foot. This divides into two branches, the outer of which runs forwards in the first space, and bifurcates for the contiguous sides of the great toe and the next, and the inner of which passes beneath the tendon of the Flexor longus pollicis and inner- most head of the Plexor brevis pollicis, to the inner side of the great toe. 4. The nerves to the Interossei muscles of the first and second spaces are now traceable from the Deep division of the External Plantar nerve. The Plantar arch is now fully exposed. If the whole of the External Plantar artery is to be uncovered, it will be necessary to remove the posterior part of the Abductor pollicis muscle and the lower portion of the Internal Annular ligament. INDEX. Abdomen. Structures exposed on opening, 129, § 1-4. Layers of wall of, in pubic and inguinal regions, 119, § a-k. Anastomosis. On the Acromion process, 71, § 2. Beneath the Complexus muscle, 16, § 6. About the elbow-joint, 87. Beneath the Tensor vaginas femoris muscle, 175, § 8. Arch. Aortic, structures crossing, 60, § a-e. Palmar, deep, formation and branches of, 107, § 3. Palmar, superficial, formation and branches of, 103, § 6. Plantar, formation and branches of, 194, § 6. Artery. Femoral, branches of, 170, § 7. Intercostal, anterior, sources of, 52, c. Plantar, external, distribution of, 190, § 9 ; 192, § 6 ; 194, § 6 ; 195, $ 2. Plantar, internal, distribution of, 189, § 8. Aktert I Profunda femoris, branches of, 173, § 2. Sciatic, termination of, 178, § 6. Thyroid axis, distribution of, 13, % 13. Vertebral, relations in interverte- bral foramina of, 18. Axilla. Position of arteries in, 75, § 5. Canal. Hunter's, structures contained in, 124, § V. a. Cord. Spermatic, constituents of, at in- ternal ring, 126, § d. Dissection op Adductor pollicis muscle, 97. Anastomoses about elbow, 82. Arch, deep palmar, 100 ; plantar, 187. Azygos major vein, 62. Circumflex arteries, anterior and posterior, 70. Cord, spinal, in cervical region, 40. Dorsal nerve, first, 33. Eustachian tube, 18. 198 INDEX. Dissection or {continued) Plexor longus polliois manus mus- cle, 92. Gluteus minimus muscle, 173. Hypoglossal nerve, 24. Interosseous arteries, 108. Kidney, posterior surface of, 131. Mammary, internal, artery, 48. Musculo-spiral nerve, 77. Obturator nerve, 118. Orbit, through outer wall, 1. Otic ganglion, 18. Peroneal artery, 182. Popliteus muscle, 177. Portal vein, 129. Profunda femoris artery, 167. Pudic artery, 151; another mode, 145 (foot-note). Sacral plexus, anterior surface of, 143 ; posterior surface of, 138. Supinator brevis muscle, 88. Trachea, anterior surface of, 55. Vertebral artery, 7. Fascia. Cervical, deep, arrangement at root of neck, 57, § III.; 58, § 1. Lumborum, formation of, 133. Palmar, description of, 101, § 2 ; structures between the processes of, 102, § 5. Pelvic, description of, 160 ; dis- section of, 144, § a-g. Plantar, description of, 188, § 6 ; structures between processes of, 187, § 2. Popliteus muscle, of, 180, § 1. Kecto-vesical, dissection of, 145 ; §11. Temporal, structures between the layers of, 3, § d. Fossa. Isckio-rectal, boundaries of, 154, § 5, 6, 7 ; contents of, 154, § 8, 9, 10. Gland. Parotid, structures contained in, 26, § 1-3. Submaxillary, structures con- tained in, 27, § c. Ligament. Annular, anterior of wrist, attach- ment of? 93, § II. Triangular, of urethra, note on, 160. Mediastinum. Structures contained in posterior. Add Trachea and omit Sym- pathetic cord, 65, § 1-5. Membrane. Costo-coracoid, structures perfo- rating, 35, § 2. Muscle. Accessorius pedis, insertion of, 191, § a. Complexus, parts beneath, 44. Deltoid, parts beneath, 73, § 1-12. Extensor tendon, muscles arising by common, 85, § 7. Extensors, deep layer of, at back of forearm, 117, § 1-5. Flexor longus pollicis pedis, in- sertion of, 191, § 2. Flexor tendon, muscles arising by common, 85, § 3. Flexor sublimis digitorum, ar- rangement of tendons beneath Annular ligament, 95, § 1. Gluteus maximus, parts beneath, 140, § 5-19 ; 156, § 1-10. INDEX. 199 Muscle (continued). Hyoglossus, structures in relation with, 30, § 7-9. Lumbricales of hand, origins of, 105, § 3. Lumbricales of foot, origins of, 191, % b. Pterygoid, external, structures in relation with, 21, § 3-5. Nerve . Buttock, cutaneous nerves of, 174, § 1-5. Crural, anterior, distribution of, 179, § 9. Median, in hand, distribution of, 104, § 9. Obturator, distribution of, super- ficial division, 125, § 8 ; deep division, 125, § 26. Occipital, third, distribution of, 8, §7. Plantar, external, 190, § 11 ; 192, § 7; 194, § 7; 195, § 4 ; in- ternal, 190, § 10. Pudic, distribution of Perinseal branch, 155-8, § 1-4. Sacral plexus, vide Plexus. Sacral nerves, loops of posterior primary branches of, 140, § 3, 13. Saphenous, external, formation of, 179 (foot-note). Splanchnics, origin of, 66, § 5 ; endings of, 69, § 7. Ulnar in palm, 104, § 8 ; 107, ,§6. Palm or Hand. . Cutaneous vessels and nerves of, 101, §3-6. Palm of Hand | Median nerve, distribution in, 104, §9. Ulnar nerve, distribution in, 104, §8; 107, §6. Pelvis. Outlet of, parts closing, 146, § 1-8. Side view of, dissection of, 144, § a-g; structures seen in, 146, 1 1-16. Perineum. Anterior triangle of, 156. Plexus. Obturator, formation of, 124, § V. a; 72, §3, 4. Sacral, formation and origin of branches of, 142, § 1-10 ; 150, § 7 ; 159, § 4-6. Relations of External and Internal Cutaneous nerves to veins of bend of elbow, 83, § 3, 4. Intercostal nerve, artery, and vein to one another, 66, § 6. Median nerve to superficial Palmar arch, 105, § 9. Mesenteric arteries and veins to one another, 130, § a, b, c, d. Obturator nerve, artery, and vein at wall of pelvis, 145, § 3. Omentum, lesser, structures con- tained in, 129, § 1-3. Posterior Interosseous artery to te"ndonof Extensorcarpi ulnaris, 113, § 22. Pudic nerve and Perineal branch to artery in Ischiorectal fossa, 154, § 9. 200 INDEX. Relatione of (continued). Root of lung (right), structures contained in, 65, vide Errata. Spine of Ischium, structures cross- ing, 157, § 7. Sheath. Of Rectus, formation of, 120, $D, E. Crural, 170, % 6. Sole of Foot. Cutaneous vessels and nerves of, 187, §3, 4, 5. External and Internal Plantar ar- teries, vide Artery. External and Internal Plantar nerves, vide Nerve. Space. Mediastinal, posterior, vide Me- diastinum. Sub-occipital triangular, bounda- ries of, 15, § 2 ; contents of, 15, §5; 16, §1. Space (continued). Triangular, of neck, posterior, structures contained in, 9-11, § 1-30, omitting § 13, 16, 17. Triangular, at bend of elbow, 84-5, § 1-4; 85-6, 10-13. Triangular, of Perinseum, anterior, vide Perineum. Triangular and quadrilateral, of Scapula, from behind, 73 ; from the front, 75, § 2. Spine of Ischium. Structures crossing, 157, § 7. Styloid Process. Structures attached to, 29, § 1-3. Vein. Arm and forearm, cutaneous of, 83, §1. Saphenous, long, radicles of, in thigh, 122, § 1 ; 168, § 5. ERRATA. Page 23, § VII. 2, for " muscle," read " nerve to the Internal Pterygoid muscle." Page 32, two lines from bottom, for "Facial," read "Lingual." Page 65, nine lines from top, for " from before backwards," read " from behind forwards.'' CHISWICK PRESS: — C, WHITTINGHAM AND CO. TOOKS COURT CHANCERY LANE. MUD I riPitllJll