THE UPPER EXTREMITIES. 



173 



the subclavius muscle. The clavicle is occasionally re- 

 moved for sarcoma. 



The scapula or shoulder blade, so called from its shape, 

 is a large, flat, triangular bone with a prominent ridge, 

 the spine, crossing its dorsum or posterior surface near its 

 upper edge. It extends from the second to the seventh rib, 

 with its posterior margin parallel to and about one inch 

 from the dorsal vertebrae. The head, in which is situated 



Coracoid process. 



Spine. 



Superior angle 

 Supragpinous fossa. " 



Acromion. 



~~* Neck of scapula . 



Infraspinous fossa. 



Axillary border. 



Inferior angle. 



FIG. 69. Left scapula, posterior surface (after Toldt). 



the glenoid cavity for articulation with the humerus 

 or upper arm bone, is surrounded by a slight con- 

 striction, the neck. Above it projects the coracoid 

 process, so calledjrom its fancied resemblance to a crow's 

 beak. This can usually be felt about one inch from 

 the juncture of the outer and middle thirds of the clav- 

 icle and from it arise the short head of the biceps and 

 the coraco-brachialis muscle. The acromion process 

 at the end of the spine extends out beyond the glenoid 

 cavity posteriorly and affords attachment to the del- 



