MEDIAN AND RADIAL NERVES 289 



The median nerve runs downward in the arm, close under the 

 border of the biceps muscle. It then passes in front of the elbow 

 joint into the forearm, and continues between the layers of flexor 

 muscles to the palm. 



In the forearm it supplies: Flexor carpi radialis. 



Flexor digitorum (sublimis). 



Flexor digitorum profundus (partially). 



Pronators. 

 In the hand it supplies: Thumb muscles (except one and a half). 



The radial nerve passes to the back of the arm, winding across 

 the humerus in the radial groove, under the triceps muscle (Fig. 

 184). 



Just above the elbow it divides into two branches, the deep and 

 superficial branches of the radial nerve. 



The superficial branch is a cutaneous nerve. It runs downward 

 in the radial side of the forearm to supply integument of the hand 

 and fingers, posteriorly. 



The deep branch passes to the back of the forearm, lying under 

 cover of extensor muscles, all of which it supplies. 



Branches of the radial nerve: 



In the arm: To the triceps. 



To brachio-radialis. 



To brachialis (partially). 

 Branches of the deep branch of the radial nerve: 



In the forearm: To the extensor carpi radialis (long and 



short). 



To the extensor digitorum (communis). 



To the extensor of index finger. 



To the extensor of little finger. 



To the extensors of the thumb. 



To the Supinators. 



Resume.' The general distribution of the muscle nerves arising 

 from the brachial plexus, is to deep muscles of the neck and the 

 external respiratory muscle (anterior serratus); to shoulder and 

 axillary muscles; arm, forearm and hand. 



The three long muscular nerves derived from the brachial plexus 

 are the ulnar nerve from the medial cord, running down behind 

 the medial epicondyle into the forearm and hand (supplying ulnar 

 muscles, little finger muscles and the interossei, and a part of the 

 thumb group) ; the median nerve from the medial and lateral cords, 

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