BRACHIAL PLEXUS OF NERVES IN MAN 341 



the plexus before the fourth nerve joins the fifth. In one other 

 case the suprascapular arises from the ventral division of the 

 fifth cervical nerve (fig. 15). 



From the above it will be seen that in 30 plexuses out of 172 

 it can be surely determined that no nerve caudal to the fifth 

 cervical enters the plexus. In 15 of these, the fourth nerve may 

 contribute but in the remaining 15 plexuses the suprascapular 

 comes exclusively from the fifth cervical nerve. 



There are 142 cases from which the sixth cervical nerve can 

 not be excluded from the suprascapular nerve. In 93 of them 

 the suprascapular may receive fibers from the fourth cervical 

 nerve (group 1 plexuses) and in 49 can receive no such fibers 

 (groups 2 and 3 plexuses). It will be seen then that while the 

 plexuses in which the suprascapular nerve receives no fibers 

 from the sixth cervical nerve are almost equally distributed be- 

 tween those with and those without a branch from the fourth 

 cervical nerve; that the plexuses in which the sixth cervical nerve, 

 that is, a more caudal nerve, may contribute to the suprascapular 

 nerve are nearly twice as many of them in the group with a 

 branch from the fourth cervical as in the group without this 

 nerve. 



If the plexuses of group 1 are more cephalic in position we 

 should expect to find fewer instances among them in which the 

 suprascapular nerve receives fibers from the sixth cervical nerve 

 than in the more caudally placed plexuses of groups 2 and 3, 

 while the reverse appears to be the case. It must, of course, 

 be remembered that some of the plexuses in which fibers from 

 the sixth nerve could not, by dissection, be excluded from the 

 suprascapular nerve would show, if macerated in nitric acid, that 

 fibers from this nerve did not enter into the formation of the 

 suprascapular. 



Wichmann reports upon only 34 cases of suprascapular nerve 

 from the literature, in 17 of these it arose from the fifth and 

 sixth cervical and in 17 from the fifth cervical nerve alone. 

 Schumacher gives the fifth cervical as the dominant spinal nerve 

 supplying fibers to the suprascapular but he also notes in his 

 table the presence of fibers from the sixth and occasionally from 



