BRACHIAL PLEXUS OF NERVES IN MAN 355 



division of the seventh cervical nerves; one root from the fifth, 

 one from the ventral division of the cephalic trunk and one from 

 the ventral division of the seventh cervical nerve; one root from 

 the ventral division of the cephalic trunk, one from the ventral 

 division of the seventh and one from a ventral branch from the 

 eighth cervical that goes to the lateral fasciculus (fig. 27); one 

 root from the lateral fasciculus of the plexus and two from the 

 ventral division of the seventh cervical nerve. 



The three plexuses in which there are four roots have the 

 same arrangement, one root comes from the ventral division 

 of the cephalic trunk, one from the lateral fasciculus and two 

 roots from the ventral division of the seventh cervical nerve. 

 In one of these the root that comes from the cephalic trunk gives 

 off a branch to the phrenic nerve. 



In the total of 166 records there are only 15 cases in which the 

 seventh cervical nerve may not contribute to the lateral anterior 

 thoracic nerve and as 14 of these are in the group where there 

 is but a single root to the nerve it makes one suspicious that in 

 spite of all our care a second root may have been broken or over- 

 looked. These 15 cases are nearly equally distributed between 

 the group 1 and group 2 of plexuses, 8 of group 1 and 7 of group 

 2. There are 87 cases, or 52.40 per cent, in which the fourth, 

 fifth, sixth and seventh cervical nerves may send fibers to the 

 lateral anterior thoracic, and 51, or 30.72 per cent, in which the 

 fifth, sixth and seventh may contribute. There is one plexus 

 in which the fourth, fifth, sixth, seventh and eighth cervical 

 nerves can none of them be excluded. This is the only instance 

 in which fibers may come from the eighth. The sixth and seventh 

 are the only contributing nerves in 3 instances and the seventh 

 alone in 9. 



Herringham believed that the seventh cervical nerve always 

 contributes to the lateral anterior thoracic. He reports on 13 

 dissections that the fifth and sixth cervical nerves' also contribute 

 to it in 5 instances and the sixth only in 8 cases. I can be sure 

 that the fifth cervical does not enter the nerve in only 12 cases 

 out of 166. 



