MUSCLES OF OUTSIDE OF THE SHOULDER 2O5 



extensor of the arm, which reaches from the upper angle 

 and the posterior border of the scapula, to the point of 

 the elbow and the inside of the arm. This muscle is a 

 very important one. 



o, 0, /, Are the three divisions of another muscle concerned in 

 the same office with p, arising from the shoulder-blade 

 and the lower bone of the shoulder, and likewise attached 

 to the point of the elbow by a very powerful tendon. 



t. This is the middle flexor, which is one of the numerous 

 and powerful muscles which bend the leg. It is also 

 represented at e, Plate vi, fig. 2, and is the muscle which 

 bends the shank-bone, because it is situated precisely in 

 the middle of the back part of the arm. It has its origin 

 from the inner head of the lower bone of the shoulder, 

 and is inserted into one of the bones on the inner side 

 of the knee. The other is seen at 2, fig. i, and is called 

 the external flexor of the leg, in consequence of lying on 

 the outer side of the arm, towards the back. It is in- 

 serted on the outer head of the lower bone of the 

 shoulder ; advancing towards the knee, it is tendinous ; 

 and the tendon divides into two portions, one of which 

 is inserted into the same bone of the knee, and the other 

 into the outer small bone of the leg. The internal flexor 

 is exhibited at -, Plate vi, fig. 2. 



u. This is one of the muscles of the lower bone of the 

 shoulder. It is the external one, whose office is to 

 bend the arm. It arises from the inner and back part 

 of the neck and body of the lower bone of the shoulder, 

 and turns obliquely round it, and is inserted into the 

 inner and upper part of the bone of the arm. 



w. This is the extensor of the leg ; it is the principal one of 

 the fore arm, is of considerable bulk, and occupies the 

 front part of the arm. It takes its rise from the lower 

 portion of the body of the lower bone of the shoulder, 

 and from its outer head. As it descends down the arm, 

 it becomes tendinous. This tendon passes under one of 

 the ligaments of the knee ; it then spreads out, and is 

 inserted into the fore and superior portion of the shank- 

 bone. It is also seen at e, fig. 2. 



x. The middle flexor, or bending muscle of the shank-bone. 

 This is situated immediately on the middle of the back 

 part of the arm. It arises from the inner termination of 



