The Anterior Limb. 209 



(b) 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. 



(c) 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. 



(d) 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 deep artery (a. profunda brachii), see p. 215. 



**The axillary vein l 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. 



