BRACHIAL PLEXUS OF NERVES IN MAN 363 



plexus all three branches come from the cord formed by the 

 union of the dorsal divisions of the cephalic and intermediate 

 trunks and in another one branch from this same cord and the 

 other two from the posterior fasciculus of the plexus. In the 

 first of these two last mentioned cases, there are two and in the 

 second case there is one additional nerve to the subscapularis 

 muscle but these are grouped with the axillary subscapular nerve. 



From the above it will be seen that one subscapular nerve 

 arises from the dorsal division of the cephalic trunk in 89 cases, 

 or 56.68 per cent of the cases; from the cord formed by the union 

 of the dorsal divisions of the cephalic and intermediate trunks 

 in 30 or in 19.10 per cent; from the posterior fasciculus in 44 or 

 in 28.02 per cent; and from various other divisions of the plexus 

 in the other cases. 



The subscapular nerve arises from the fifth cervical nerve in 

 one case and from the seventh in 8 instances. In all the other 

 cases it arises in such a way that two or more nerves may con- 

 tribute fibers to it. In 40 cases the fourth, fifth and sixth may 

 contribute and in 28 the fifth and sixth. In 22 instances the 

 fourth fifth, sixth and seventh may send fibers and in 15 the 

 fifth, sixth and seventh. In 34 plexuses all of the nerves from the 

 fourth cervical to the first thoracic and in 9 from the fifth cervical 

 to the first thoracic may contribute. Herringham ('87) reports 

 on 41 cases and states that in the majority of cases the fifth nerve 

 only sends fibers to the subscapular, but that often the sixth 

 contributes but in no instance the seventh and eighth cervical. 

 I found 8 plexuses in which the seventh cervical was the only 

 nerve that could send fibers to it. 



THE AXILLARY SUBSCAPULAR NERVE 



The axillary subscapular nerve (lower subscapular) is usually 

 described as arising from the posterior fasciculus of the plexus 

 or one of the roots of this. It supplies the teres major muscle 

 and the axillary border of the subscapularis muscle. 



Among the 157 satisfactory records of the axillary subscapular 

 nerves in my series, the nerve arises directly from the posterior 

 fasciculus in 48 cases (fig. 2). In gne of these it receives a branch 



