THE SUPERIOR EXTREMITY 



thenar eminence ; the latter winds over the brachio-radialis to 



supply the posterior surface 

 of the forearm as far as the 

 wrist. It lies lateral to the 

 dorsal cutaneous nerve of the 

 forearm (lower external cut- 

 aneous branch of musculo- 

 spiral). 



The medial aspect of the 

 arm is supplied above by the 

 Inter co sto-brachial Nerve (T.2), 

 (p. 32), and, more posteriorly,, 

 by the Dorsal Cutaneous Nerve 

 of the Arm (C. 8) (Internal 

 Cutaneous Branch of Musculo- 

 spiral), which arises before the 

 radial nerve enters its groove 

 on the back of the humerus. 



Distal to this area the skin 

 is supplied by the Medial 

 Cutaneous Nerve of the Arm 

 (Lesser Internal Cutaneous 

 Nerve) (T. i and 2), as far as 

 the medial epicondyle. The 

 skin covering the biceps is 

 supplied by the Medial Cut- 

 aneous Nerve of the Forearm 

 (Internal Cutaneous Nerve) (C. 

 8 and T. i), which pierces the 

 deep fascia at the insertion of 

 the coraco-brachialis and ac- 

 companies the basilic vein. 

 Just proximal to the medial 

 epicondyle it divides into volar 

 (anterior) and ulnar (posterior) 

 FIG. 14. Schematic Representation of branches which Supply the 

 the Distribution of the Spinal Nerves m edial half of the forearm as 

 to the Skin on the Anterior Aspect , ^, , 



of the Upper Limb. far as the WTlst ' 



It will be observed that 



V.A.L, Ventral axial line. 



the skin on the lateral aspect 



of the limb is supplied by the upper nerves of the brachial 

 plexus, and that on the medial side by the lower. The innerva- 



