6o DISSECTION OF THE VASCULAR SYSTEM. 



20. Near the point where the axillary artery enters 

 the arm it gives off a large branch from its posterior 

 border which divides into three arteries : 



a. The Long Thoracic Artery, a small branch 

 passing along the side of the thorax and distributed 

 chiefly to the pectoral and latissimus dorsi muscles. 



b. The Sub-scapular Artery, a large branch dis- 

 tributed to the sub-scapular muscles. 



c. The Circumflex Artery, passing obliquely 

 round the humerus and distributed chiefly to the 

 triceps extensor muscle of the arm. 



21. The Brachial Artery. After reaching the arm 

 the axillary artery is known as the brachial. It gives 

 off muscular branches in the arm, and at the elbow 

 divides into two branches for the fore-arm. 



