CHAPTER XI. 



Tab. XIII. — THE MUSCLES OF THE ARM. 



Fig. 1. a, the biceps, (biceps flexor cubiti) arise by two portions 

 Irom the scapula ; they form a thick mass of flesh in the middle of the 

 arm, which is finally inserted into the upper end of the radius ; h, the 

 brachicBUS internus, arises from the middle of the os humeri, and is 

 inserted into the ulna. Both these muscles bend the fore-arm. c, the 

 longus et brevis brachicBus externus ; these are better named aa one 

 muscle, triceps extensor cubiti. It is attached to the inferior edge of 

 the scapula, and to the os humeri, by three distinct heads, which unite 

 and invest the whole back part of the bone , becoming a strong tendon 

 which is implanted into the elbow. It is a powerful extensor of the 

 fore-arm. d, the anconaus, a small triangular m\iscle, situated at the 

 outer side of the elbow : it assists the last muscle. 



FiG.l and 2. e, e, the annular ligament of the wrist, under which 

 pass the tendons of the muscles of the fingers. 



Fig. 1. /, the deltoid muscle ; the muscle at the shoulder by which 

 the arm is raised. 



