BRACHIAL PLEXUS OF NERVES IN MAN 339 



muscle appears to arise from the lateral fasciculus of the plexus 

 or from the musculocutaneous nerve, the fibers may be found to 

 come from the seventh cervical nerve. 



In my series of 109 records of the nerve to the musculocutane- 

 ous it was represented by a single nerve in 61, or 55.45 per cent 

 of the 109 instances. The muscle is supplied by 2 nerves in 34, 

 or 31.19 per cent; by 3 nerves in 11 cases, or 10.09 per cent; and 

 by 4 nerves in only 3 instances or 2.57 per cent. It is probable 

 that in some cases one or more of the nerves to the muscle may 

 have been broken in the dissection or overlooked in the veri- 

 fication. It is altogether probable that in some cases at least 

 there was an additional nerve that was not exposed since the 

 foramen in the coracobrachialis muscle through which the 

 musculocutaneous nerve passes was not opened up until late in 

 the dissection and one of the branches to the muscle is often given 

 off by the musculocutaneous nerve during its passage through 

 the muscle. 



The nerve to the coracobrachialis in my series arises in such a 

 way that fibers of only the fifth and sixth nerves might enter it 

 in two instances and in only 4 instances does it arise in such a 

 way that the fibers of all the nerves but the seventh cervical can 

 be excluded. In 61 instances its origin is such that the fibers 

 of the fourth to the seventh cervical nerves inclusive might 

 enter and in 31 cases fibers from the fifth to the seventh. In 11 

 plexuses fibers of the nerves caudal to the seventh cervical could 

 not be excluded. In 6 of these the fourth to the eighth cervical 

 and the first thoracic ; in 4, the fifth to the eighth cervical and the 

 first thoracic ; and in 1 the fourth to the eighth cervical might 

 have contributed. 



Herringham found the nerve received its fibers from the seventh 

 cervical nerve only, in all cases, except one in which there were 

 fibers from the sixth cervical also. 



THE SUPRASCAPULAR NERVE 



The suprascapular nerve is usually described as arising from 

 the cephalic trunk of the brachial plexus formed by the junction 

 of the fifth and sixth cervical nerves. 



