458 APPENDIX. 
(2) The anterior thoracic was probably cut in dissecting the 
pectoral muscles; it may be found, but its distal end is probably 
cut off. 
(4) The long thoracic is easily followed. 
(c) The subscapular. Follow the main artery before dissecting 
its branches. Where the subscapular disappears between the long 
head of the triceps, the latissimus dorsi, and the scapula, it may be 
traced and found again as follows: Remove the skin from the outer 
side of the shoulder, —taking great pains to remove only the skin and 
not to injure the vena cephalica (p. 319), a large vein that lies just 
beneath the skin on the lateral surface of the shoulder, coming from 
the elbow. The branches of the subscapular will be found appearing 
on the lateral surface of the arm in the angle between the spino- 
trapezius, the long head of the triceps, and the infraspinatus. The 
distal branches may then be followed. 
(¢@) The posterior circumflex (p. 296) may be traced distad in a 
similar manner, by seeking it beneath the caudal border of the 
spinotrapezius. (Do not injure the vena cephalica.) 
(e) The other branches of the brachial artery and vein present no 
difficulty till we come to the collateralis radialis superior (Fig. 122, x). 
This must be traced with great care, along with the vena mediana 
cubiti (p. 319, and Fig. 122, y). Remove the skin from the extensor 
side of the forearm, taking great pains not to remove anything more 
than the skin. The artery and vein lie beneath the skin and should 
be traced to the hand (see Fig. 130). 
Along with the collateral radial artery trace the vena cephalica 
(p. 319, and Fig. 130, @ and c). Follow it across the shoulder, 
noting the branch to the posterior circumflex vein. 
The remainder of the blood-vessels of the arm present no special 
difficulty (see Figs. 123 and 124), 
Make a diagram of the subclavian artery, as far as dissected. 
III. Remove the skin from the sides of the neck, exposing the 
sternomastoid muscles and the external jugular veins crossing them 
(see Fig. 131). Clean the surface of the sternomastoid muscles, 
without injuring the vein; separate the two muscles caudad, and cut 
each close to the attachment to the sternum. Find the sternohyoid 
and sternothyroid muscles, and cut them close to their attachment 
to the first rib. Uncover the right side of the thorax in the same 
way as the left, cut the ribs without injury to the nerves and vessels 
of the right axilla, cut the internal mammary artery and vein (after 
tying the latter), and thus remove the sternum with nearly the entire 
thoracic wall. 
The blood-vessels of the thorax may now be more completely 
exposed, (If the nerves are to be dissected on the same specimen, 
find the phrenic, vagus, and sympathetic nerves (Fig. 157), and take 
the greatest pains not to injure them.) 
1. The coronary arteries and the veins of the heart (pp. 281 and 
316). 
