(b) 
(c) 
(d) 
THE ANTERIOR LIMB. 209 
The thoracoacromial artery (a. thoracoacromialis); it 
arises from the ventral wall or in common with (c), passes 
between the pectorales tertius and quartus, then between 
the p. superficialis and the cleidohumeralis. It distributes 
branches to these muscles, and taking a position ventral to 
the clavicle, passes to the platysma and the skin. 
The lateral (long) thoracic artery (a. thoracalis lateralis) 
arises from the posterior wall or in common with (b); 
distributes branches chiefly to the p. secundus, and sends 
a long superficial branch, the external thoracic artery, 
backward through the cutaneus maximus muscle. This 
vessel is usually conspicuous in the female, where it distri- 
butes external mammary branches to the mammary 
glands. It anastomoses posteriorly with the superficial 
epigastric branch of the femoral. 
The subscapular artery (a. subscapularis) is a large 
branch given off from the distal portion of the axillary 
artery. It distributes branches to the subscapularis muscle, 
and sends a thoracodorsal branch into the latissimus 
dorsi. Perforating the teres major muscle near the axilla, 
it appears on the lateral surface of the shoulder, where it 
sends a large branch into the inferior portion of the trapezius, 
and a second into the cutaneus maximus. The latter vessel 
supplies the proximal end of the long head of the triceps, 
but its chief portion passes backward uniting with an 
anterior superficial branch of the iliolumbar, and thus 
forming one of three superficial anastomoses covering the 
abdominal region and in the female the mammary glands. 
(e) The circumflex arteries of the head of the humerus, see p. 215. 
(f) 
The deep artery (a. profunda brachii), see p. 215. 
**The axillary vein (v. axillaris) begins at the medial side of the 
humerus and crosses the axillary fossa to the first rib whence it is 
continued as the subclavian. It receives the lateral thoracic 
and subscapular veins, which accompany the corresponding 
arteries, and also the cephalic vein (p. 216), which reaches the 
medial side of the shoulder from the anterior surface of the arm by 
passing between the teres major and subscapular muscles near the 
neck of the scapula. 
