BRACHIAL PLEXUS OF NERVES IN MAN 359 



In 2 other cases the axillary nerve arises from the dorsal 

 division of the cephalic trunk and receives a branch. This comes 

 from the trunk formed by the union of the dorsal branches of 

 the intermediate and caudal trunks in one case and from the 

 dorsal division of the intermediate trunk in the other case and 

 gives off the thoracodorsal nerve before joining the axillary. 



In the other one of the 35 cases, the axillary nerve arises from 

 the dorsal division of the intermediate trunk. 



The axillary nerve gives off no other nerves in 80 cases, or 46.24 

 per cent. The axillary subscapular nerve arises from it in 89 

 or 55.44 per cent. 



It will be noted that in nearly 80 per cent of the above cases 

 the nerve arises from the dorsal fasciculus of the plexus and in 

 these cases it is not possible to tell whether or not all of the cervi- 

 cal nerves that go to the dorsal fasciculus send branches to the 

 axillary nerve. From my maceration experiments I do not believe 

 that as a rule they do. At the same time I cannot now exclude any. 



The axillary nerve may receive fibers from any of the nerves 

 from the fourth cervical to the first thoracic inclusive, in 92 

 instances, 53.17 per cent; from the fifth cervical to the first 

 thoracic in 44 cases, 25.43 per cent; from the fourth to the eighth 

 cervical in one case; from the fifth to the eighth cervical in 2 

 cases; from the fourth to the seventh cervical in 10; from the 

 fifth to the seventh cervical in 6; from the fourth to the sixth 

 cervical in 6 ; and from the fifth and sixth cervical nerves in 9 cases. 



Wichmann has collected from the literature 142 cases. In 

 112 of these the fifth and sixth cervical nerves only entered the 

 plexus; in 21 the fifth, sixth and seventh; in 7 the fifth, sixth, 

 seventh and eighth cervical and first thoracic; and in 6 cases 

 the fifth only. Schumacher in his 10 cases found the fifth and 

 sixth cervical 7 times and the fifth, sixth and seventh 3 times. 

 From my experience so far with macerated plexuses I am in- 

 clined to believe that the eighth cervical and first thoracic will 

 be found sending fibers to the nerve seldom if at all. In what 

 proportion the seventh will be found, I am unable to say from my 

 maceration experiments. It appears to be present somewhat 

 more often than previously reported. 



