BRACHIAL PLEXUS. 323 



nerve, which passes down the median line of the arm 

 and forearm, beneath the anterior annular ligament ; it 

 is ultimately distributed to the palmar surface of all the 

 digits except the little finger and adjoining side of ring- 

 finger. It sends off numerous branches in the forearm 

 to the muscles and the anterior interosseous, which runs 

 along the median line of the interosseous membrane and 

 supplies the deep muscles. It terminates beneath the 

 pronator quadratus in a ganglion. 



6. The ulnar is the continuation of the inner cord, 

 and runs along the inner side of arm, passes behind the 

 internal epicondyle, along the ulnar side of forearm, ano\ 

 terminates in the skin of the little finger and adjoining 

 side of ring-finger. The ulnar sends off numerous 

 branches to the muscles of the forearm and the integu- 

 ment, along the inner side of forearm and hand. 



7. The internal cutaneous, a small branch from the 

 inner or lower cord, runs down the inner side of arm, 

 becomes subcutaneous, passes over the medio-basilic 

 vein, and is distributed to the integument of inner and 

 posterior part of forearm. 



8. The lesser internal cutaneous, or nerve of Wris- 

 berg, arises from the inner cord above the internal cuta- 

 neous. It is commonly joined by a branch from one of 

 the intercostal nerves, called the intercosto-humeral. It 

 is distributed to the integument along the inner side of 

 elbow and forearm. 



9. The musculo-spiral is the continuation of the 

 posterior cord, and is the largest branch of the plexus. 

 It runs downward and outward, winds around the hu- 

 merus from within backward, lying in the musculo-spiral 

 groove, and descends between the origins of the brachi- 

 alis anticus and supinator longus muscles to the elbow, 

 where it divides into the radial and posterior interosse- 



