BRACHIAL PLEXUS OF NERVES IN MAN 351 



the caudal trunk of the plexus and has no anastomosis with the 

 intercostobrachial. In 2 of these it arises in combination with 

 the medial brachial cutaneous; in one with the medial anterior 

 thoracic nerve; and in one with both of these (fig. 27). 



There are 7 cases in which the medial antibrachial cutaneous 

 nerve arises from the ulnar nerve and has no anastomosis with 

 the intercostobrachial. In one of these it arises from a stem 

 common to it and the medial anterior thoracic. 



There are 4 instances where the nerve arises from the first 

 thoracic without connection with the intercostobrachial. In 

 one of these it arises in common with the medial brachial cutane- 

 ous nerve. 



There are 6 plexuses in which 2 nerves were recorded as medial 

 antibrachial cutaneous. In 2 these both arise from the medial 

 fasciculus of the plexus, and in one of these one nerve anastomoses 

 with the intercostobrachial and the other arises from a stem in 

 common with the medial brachial cutaneous; in the third case, 

 both nerves come from the caudal trunk ; in the fourth both come 

 from the medial fasciculus, the first by a common stem with the 

 medial brachial cutaneous and the second singly. In the fifth 

 instance with two nerves, one arises from the medial fasciculus 

 and the other a slender fascicle from the eighth cervical nerve. 

 In the sixth instance one comes from the caudal trunk and one 

 from the medial fasciculus of the plexus. 



There are 143 or 82.18 per cent of the plexuses in which the 

 medial antibrachial cutaneous nerve arises from the medial 

 fasciculus of the plexus besides 3 in which there are 2 nerves. 

 There are 16 plexuses in which the nerve arises from the caudal 

 trunk besides 2 in which the nerve is double. 



In all the plexuses except 4 in which the nerve arises from the 

 first thoracic nerve only, we cannot exclude fibers of the eighth 

 cervical as well as the first thoracic. There are 170 such cases 

 or 97.70 per cent. In 3 of the 5 plexuses of type A that are 

 included in the above, the seventh cervical nerve also cannot be 

 excluded. The medial antibrachial cutaneous nerve may re- 

 ceive its fibers from the eighth cervical and first thoracic in 167 

 cases; from the seventh and eighth cervical and first thoracic 



