THE FRONT OF THE ARM 97 



All these nerves have already been studied (p. 69) ; 

 the supraclavicular nerves were removed, and the lateral 

 brachial cutaneous nerve was displaced when the shoulder 

 region was examined. Their general positions and distribu- 

 tion of the remaining nerves should now be revised. 



The intercosto - brachial nerve supplies the skin of the 

 posterior part of the medial aspect of the arm and the 

 adjacent part of the back of the arm from the axilla to 

 the elbow (Figs. 31, 32). 



The medial cutaneous nerve of the arm pierces the deep fascia 

 at the middle of the arm, on the medial side, and supplies 

 the skin of the distal half of the medial aspect of the arm. 

 Before it pierces the fascia it gives off no branches of 

 distribution, but it may communicate with the intercosto- 

 brachial nerve (Figs. 31, 16). 



The medial cutaneous nerve of the forearm pierces the deep 

 fascia at the middle of the arm, on the medial side, some- 

 times passing through the opening which admits the basilic 

 vein. Before it becomes superficial it gives off several 

 branches which pierce the deep fascia at varying points 

 from the axilla to the middle of the arm ; those branches, 

 together with others given off after the nerve pierces the 

 deep fascia, supply the skin on the medial part of the 

 anterior aspect and the anterior part of the medial aspect 

 of the arm, from the axilla to the elbow. The two terminal 

 branches of the nerve, volar and ulnar, supply the skin of 

 the medial part of the volar aspect, and the ulnar border 

 of the forearm as far as the wrist. As the volar branch 

 leaves the arm it usually passes between the median 

 cubital vein and the lacertus fibrosus. The ulnar branch 

 descends either in front of or behind the medial epicondyle 

 (Figs. 31, 32). 



The posterior brachial cutaneous nerve supplies the skin 

 of the middle of the back of the arm from the axilla to 

 the elbow. 



The dorsal cutaneous nerve of the forearm usually pierces 

 the deep fascia in two parts, a short distance distal to the 

 insertion of the deltoid. The proximal branch supplies 

 some twigs to the lateral part of the back of the arm, and 

 then turns forwards to supply the skin of the lateral part 

 of the front of the arm, from the level of the insertion of 

 the deltoid to the elbow. The distal branch supplies twigs 



VOL. i 7 



