BRACHIAL PLEXUS OF NERVES IN MAN 361 



In 17 plexuses where the nerve is single it arises from the cord 

 formed by the union of the dorsal divisions of the cephalic and 

 intermediate trunks (fig. 11). 



In 13 instances the single nerve arises from the posterior 

 fasciculus of the plexus (fig. 21). In 2 of these there is an addi- 

 tional branch that I regard as belonging to the axillary subscapu- 

 lar nerve. 



In 7 cases the nerve arises from the dorsal division of the 

 intermediate trunk (seventh cervical nerve) and in one case 

 from the ventral division of this. 



In one plexus the subscapular nerve comes ftom the fifth 

 cervical nerve; in one by two roots, one from the cephalic trunk 

 and the other from the dorsal" division of this ; in another, by three 

 roots, one from the cephalic trunk with the suprascapular nerve, 

 one from the lateral fasciculus of the plexus, and one from the 

 intermediate trunk. In one plexus, the nerve comes from the 

 dorsal division of the cord formed by the union of the cephalic 

 and intermediate trunks and in one it comes from a cord formed 

 by the union of the intermediate and caudal trunks. In one 

 instance the nerve arises from the radial nerve. In this case 

 the axillary subscapular and the thoracodorsal nerves also arise 

 from the radial nerve. 



In 7 of the plexuses where there is a single nerve this divides 

 almost immediately after its origin into 2 branches in 5 cases 

 and 3 branches in 2. The nerve frequently breaks up into several 

 branches before entering the muscle but my records do not show 

 the method of branching. 



In 21 of the 64 instances where there are two subscapular 

 nerves both arise from the dorsal division of the cephalic trunk 

 (fig. 2). In two of these there is another separate nerve to the 

 subscapularis muscle that comes from the axillary nerve and 

 which I have considered as a part of the axillary subscapular 

 nerve. 



In 13 cases, one of the two subscapular nerves comes from the 

 dorsal division of the cephalic trunk and the second from the 

 posterior fasciculus of the plexus (fig. 1). 



In 7 cases both branches come from the cord formed by the 



