332 ABRAM T. KERR 



of these there is given off from the lateral head an additional 

 branch that goes to the coracobrachialis muscle (fig. 22). In 

 another instance the lateral head of the median gives off a branch 

 which was said to be the lateral head of the ulnar but the nerve 

 was broken and could not be verified. In the other case the 

 branch supplies the coracobrachialis muscle. 



The lateral head of the median nerve in five instances receives 

 a branch. In one of these it is from the seventh cervical nerve 

 (fig. 23). As already noted above, this branch comes from the 

 lateral fasciculus of the plexus in two instances. In one case, 

 the lateral head of the median receives a branch from the eighth 

 cervical nerve (fig. 25), and in another from the medial fascic- 

 ulus of the plexus (fig. 26). 



From the above it will be noted that the lateral head of the 

 median gives off branches in 26 instances but that it receives 

 them in only 5 ; the medial head of the median gives off a branch 

 in but one instance while it receives branches in 54. The 

 tendency is therefore, in the great majority of cases, for the 

 branches here to pass from the lateral toward the medial side of 

 the plexus. 



The median nerve received fibers from the fifth, sixth, seventh 

 and eighth cervical and first thoracic nerves in 116 of the 136 

 cases reported by Wichmann from the literature. Schumacher 

 has added 7 cases in which the above five nerves sent fibers to 

 the median. In other words, if we disregard the fourth cervical 

 nerve, which is not accounted for by these authors, all of the 

 nerves which form the brachial plexus contribute to the formation 

 of the median nerve in 123 of the 146 cases listed by them'. In 

 the remaining 23 cases, the fifth cervical nerve failed to send a 

 branch to the median in 10 instances in Wichmann's series and 

 in 2 of Schumacher's. The first thoracic nerve failed to send a 

 branch to the median in 7 of Wichmann's and 1 of Schumacher's 

 cases. Wichmann reports 3 instances in which other cervical 

 nerves were lacking in the median, in one case it was the fifth 

 and sixth cervical nerves, in one case the sixth cervical nerve and 

 in one the eighth cervical nerve. 



In none of the 175 plexuses of my series, was it possible to be 



