196 



SURGICAL APPLIED ANATOMY. [Chap. xi. 



faces the empty glenoid cavity (Fig. 19). The sub- 

 scapularis muscle is stretched over the head of the 

 humerus, and is usually in some part torn. The supra- 

 spinatus, infraspinatus, and teres minor are stretched 



or torn, or the 

 great tuberosity 

 may even be 

 wrenched off. The 

 c o r a c o - brachialis 

 and short head of 

 the biceps are 

 tense, and are 

 immediately in 

 front of the head 

 of the humerus 

 instead of to its 

 inner side. The 

 long tendon of the 

 biceps is deflected 

 downwards and 

 outwards. It is 

 sometimes, al- 

 though rarely, 

 torn from its 

 groove. The del- 

 toid is put upon the stretch. The prominence 

 formed by the humeral head in the front of the 

 axilla depends to some degree upon the amount of 

 rotation. If the bone be rotated out the projec- 

 tion is most distinct; but if rotated in, its head 

 sinks into the axilla and is brought more in contact 

 with the scapula than with the skin. The head of 

 the bone being always carried a little downwards some 

 lengthening must in all cases really exist; but with 

 the ordinary method of measuring the limb this 

 lengthening may be replaced by a normal measure- 

 ment, or even by apparent shortening, if the head of 



Fig. 19. Subcoracoid Dislocation of the 

 Humerus. 



