496 NERVOUS SYSTEM. 



cic has its origin somewhat concealed by the scalenus anticus 

 muscle. It descends into the axilla, adhering to the serratus 

 major muscle for some distance, and is then distributed by 

 many filaments to this muscle. 



4. The Nervus Jlxillaris, or Circumflexus, comes from the in- 

 ferior part of the plexus. Immediately after its origin, it goes 

 downwards and outwards over the upper extremity of the sub- 

 scapularis muscle. It then wind* around theos humeri, between 

 the teres minor and major muscles, observing the course of the 

 posterior circumflex artery, and, finally, terminates on the un- 

 der surface of the deltoid muscle. 



This nerve sometimes gives off the subscapular nerves, and, 

 indeed, it is usual for anatomists to include the description of 

 the latter in it. As it turns around the bone, it divides into two 

 principal trunks; the superior goes to the inferior margin of the 

 infra-spinatus, and to the posterior margin of the deltoides; the 

 inferior is distributed principally in the substance of the deltoid 

 muscle, but some of its filaments, by perforating the latter, 

 reach the skin, and constitute the nervus cutaneus humeri. 

 Filaments go from the nervus axillaris, in the early part of its 

 course, to the subscapularis and the two teres muscles. 



5. The Nervus Cutaneus Internus* arises from the lower 

 part of the axillary plexus, and is one of the smallest of those 

 which go to the arm. It is situated between the median and 

 the ulnar nerve, and adheres almost as far as the elbow, to the 

 basilic vein. In its descent, this nerve detaches several small 

 filaments, which, perforating the fascia of the arm, are distri- 

 buted to the integuments of the biceps muscle, and to those on 

 the internal face of the triceps. 



Somewhat above the bend of the elbow, at the place where 

 the median basilic vein joins the basilic, but occasionally some 

 inches higher up, the internal cutaneous becomes superficial, 

 and splits into two branches of nearly equal magnitude, which 

 diverge but little from each other at first. The branch nearest 

 the internal condyle of the os humeri, lies in front of the basi- 

 lic vein, as it passes over the elbow joint; and continues in this 



* Antonius and Caldani, Tabul. CCLVIIK 



