8 TOPOGRAPHICAL ANATOMY OF 



insertion of the muscle is to the transverse processes of the last four 

 or five cervical vertebras, and the first eight or nine ribs in the 

 neighbourhood of the junction of the rib-bone and the rib-cartilage. 

 The serrated character of the border of the muscle is best marked 

 at its insertion into the fifth to ninth ribs. In this region it will 

 be observed that the precise outline of the muscle is somewhat 

 obscured by an overlapping of the yellow, elastic tunic that clothes 

 the abdominal muscles. 



M. latissimus dorsi. — This extensive muscle cannot be completely 

 examined at this stage of the dissection, but its identity should be 

 established. 



M. omohyoideus. — Being a muscle of the neck, only the origin of 

 the omohyoid 1 — from the fascia over the subscapular muscle near the 

 shoulder joint — need be examined by the dissector of the limb. 



Dissection. — The brachial plexus should be severed close to the point 

 at which it appears between the two parts of the scalenus muscle. Next 

 cut through the serratus ventralis a short distance from its scapular 

 attachment. The origin of the omohyoid muscle should also be freed. 



The body must now be turned into such a position as will permit 

 the dissection of the lateral scapular region. Though all the muscles 

 (with the exception of the latissimus dorsi) now to be examined are 

 attached to the scapula, their origins are very widespread. The 

 trapezius and rhomboid extend far into the neck, while the latissimus 

 dorsi has part of its origin as far distant as the loins. It is advisable, 

 therefore, to make an extensive surface examination before beginning 

 to turn aside the skin. The spine of the scapula can generally be 

 identified and palpated. Cranial to it is a sloping, elongated pro- 

 minence, produced by the supraspinous muscle and the prescapular 

 portion of the deep pectoral, bounded by a shallow groove that marks 

 the junction of the neck and shoulder. Caudal to the scapular spine 

 is a broader area corresponding to the infraspinous and deltoid 

 muscles. An oblique groove indicates the border of the latter muscle, 

 and ventral and caudal to it is a distinct swelling, reaching to the 

 region of the olecranon, caused by the triceps. 



Dissection. — A longitudinal incision should be made along the mid- 

 dorsal line from the level of the epistropheus to the lumbar region. 

 A vertical incision is now carried from the interscapular region (withers) 

 to well beyond the shoulder joint. The two flaps of skin thus demar- 

 cated are now to be turned aside. Immediately under the skin is the 

 cutaneous muscle, which, over the scapula, is very thin, but becomes 

 thicker as it is followed over the wall of the thorax. Its dissection from 



1 w/xos (omos) [Or.], shoulder. voeiSns [Gr.], U-shaped, from the resemblance of 

 the human hyoid bone to the letter IT. 



