570 



SPINAL NERVES. 



Fij 



287. Cutaneous Nerves of Right Upper 

 Extremity. Posterior View. 



The cutaneous portion of the nerve passes behind the median cephalic vein, and 

 divides, opposite the elbow-joint, into an anterior and a posterior branch. 



The anterior branch descends along the radial border of the forearm to the 

 wrist. It is here placed in front of the radial artery, and, piercing the deep 

 fascia, accompanies that vessel to the back of the wrist. It communicates with 



a branch from the radial nerve, and dis- 

 tributes filaments to the integument of -the 

 ball of the thumb. 



The posterior branch is given off about 

 the middle of the forearm, and passes 

 downwards, along the back part of its 

 radial side, to the wrist. It supplies the 

 integument of the lower third of the 

 forearm, communicating with the radial 

 nerve, and the external cutaneous branch 

 of the musculo-spiral. 



The Internal Cutaneous Nerve is one 

 of the smallest branches of the brachial 

 plexus. It arises from the inner cord, 

 in common with the ulnar and internal 

 head of the median, and, at its commence- 

 ment, is placed on the inner side of the 

 brachial artery. It passes down the inner 

 side of the arm, pierces the deep fascia 

 with the basilic vein, about the middle of 

 the limb, and, becoming cutaneous, di- 

 vides into two branches. 



This nerve gives off, near the axilla, a 

 cutaneous filament, which pierces the 

 fascia, and supplies the integument cover- 

 ing the Biceps muscle, nearly as far as 

 the elbow. This filament lies a little ex- 

 ternal to the common trunk from which 

 it arises. 



The anterior branch, the larger of the 

 two, passes in front of, occasionally be- 

 hind, the median basilic vein. It then 

 descends on the anterior surface of the 

 ulnar side of the forearm, distributing 

 filaments to the integument as far as the 

 wrist, and communicating with a cuta- 

 neous branch of the ulnar nerve. 



The posterior branch passes obliquely 

 downwards on the inner side of the basilic 

 vein, winds over the internal condyle of 

 the humerus to the back of the forearm, 

 and descends, on the posterior surface of 

 its ulnar side, to a little below the middle, 

 distributing filaments to the integument. 

 It anastomoses above the elbow with 

 the lesser internal cutaneous, and above 

 the wrist with the dorsal branch of the 

 ulnar nerve (Swan). 



The Lesser Internal Cutaneous Nerve 

 (nerve of Wrisberg) is distributed to the 



integument on the inner side of the arm. It is the smallest of the branches of the 

 brackial plexus, and usually arises from the inner cord, with the internal cutaneous 



