BRACHIAL PLEXUS OF NERVES IN MAN ' 343 



cephalic trunk; in 6 instances singly (fig. 8) ; and in 3 in combina- 

 tion with a branch to the phrenic nerve. In 5 of the 14 instances 

 it arises from the ventral brancli of the cephalic trunk, in 4 singly 

 and in 1 with the lateral anterior thoracic nerve. 



In 1 instance the nerve to the subclavius arises as a single 

 branch from the sixth cervical nerve and in 1 instance it arises 

 also as a single branch from the lateral cord of the plexus. The 

 cord in this latter instance is formed from the ventral branches 

 of the cephalic trunk, formed from the fourth, fifth and sixth 

 cervical nerves, combined with the ventral branch of the seventh 

 cervical nerve. 



In 54 of the above plexuses or 65.06 per cent the subclavius 

 nerve arises as a single branch. In 24 or 28.67 per cent it comes 

 from a stem common to it and a branch to the phrenic, in 3 from 

 a branch common to it and the dorsal scapular nerve, and in 2 

 from a stem from which one of the branches of the lateral anterior 

 thoracic nerve also arises. 



The records given by others of the spinal nerve or nerves from 

 which the subclavius nerve arises are very incomplete, doubtless 

 because the nerve is so delicate and so often broken in the dis- 

 section. Wichmann in his synopsis of the literature up to 1900 

 does not report clearly the number of cases recorded. He states 

 that it has been found arising from the third cervical nerve by 

 one author, from the fourth by one, and from the fifth by five 

 authors. The nerve was reported as coming from the fifth and 

 sixth cervical nerves by two authors; from the fifth, sixth and 

 seventh by 1. The sixth cervical alone gave rise to the nerve 

 in 2 instances reported by one author and the seventh and eighth 

 by 1. He gives the fifth and sixth as the normal of Renz. Schu- 

 macher reports the fourth and fifth as found in Bolk's case. In 

 his own investigations the fifth was the dominant nerve; the 

 sixth sometimes entering. My results show that out of 83 

 satisfactory records the nerve to the subclavius may receive 

 fibers from the fourth and fifth cervical nerve in 18 instances; 

 from the fifth cervical only in 21 cases; from the fourt*h, fifth 

 and sixth cervical nerves in 27 instances; from the fifth and sixth 

 cervical nerve in 15; from the sixth cervical in 1 ; from the fourth, 



