SHOULDER AND ARM. 



the axillary vessels, and on the inner side of the brachial artery 

 to the midarm; then passing behind the internal intermus- 

 cular septum it descends, with the inferior profunda artery, 

 to the interval between the olecranon and internal condyle; 

 thence it runs between the heads of the Flexor carpi ulnaris 

 to the forearm. It has no branches in the arm. [629] 



Internal Cutaneous. Arising from the inner cord, this de- 

 scends superficial to the main vessels, pierces the deep fascia 

 at the midarm, and supplies the lower half of the arm antero- 

 internally. Then accompanying the basilic vein to the elbow 

 it divides into two branches, anterior and internal, for the 

 forearm. [631] 



Lesser Internal Cutaneous. Arising from the inner cord 

 this descends between the axillary vessels, pierces the deep 

 fascia internally, and supplies the skin on the upper half, or 

 more, of the upper arm internally. It varies inversely in size 

 with the intercosto-humeral, and may be absent. [632] 



Circumflex. Arising from the posterior cord, this runs 

 downward and outward behind the axillary artery, and then, 

 with the posterior circumflex vessels, through the quadrilat- 

 eral space bounded by the humerus, Subscapularis, Teres 

 major and Triceps (long head). Then winding round the sur- 

 gical neck of the humerus it supplies the Teres minor and 

 Deltoid, ending in the latter; branches supply the shoulder 

 joint. A cutaneous branch descends under the Deltoid and 

 then runs through it, or around its lower border, to the skin 

 over its insertion, and the upper half of the arm on the outer 

 side. [632] 



Musculo-spiral. Arising from the posterior cord, this de- 

 scends behind the axillary artery, and then on the inner side 

 of the humerus, lying upon the Triceps (long head) behind the 

 brachial artery. Then running in the spiral groove behind the 

 middle third of the humerus, with the superior profunda 

 artery, it pierces the external intermuscular septum, descends 

 to the bend of the elbow, lying in front of the external condyle 



[163] 



