THOEACIC LIMBS 



541 



clavicle. The secondary points of difference between the two forms 

 are those which are associated with man's upright posture and the use 

 of the anterior extremity for other purposes than the support of the 

 body. (See Figs. 435, 436.) The position of the human scapula is 



FIG. 424. 



FIG. 425. 



LEFT SCAPULA, POSTERIOR VIEW. 



1, supraspinous fossa; 2, infraspinous fossa; 3, supe- 

 rior border; 4, coracoid notch; 5, inferior border; 6, 

 glenoid cavity ; 7, inferior angle ; 8, neck of the scapula; 

 9, posterior border or base ; 10, spine ; 11, its triangular 

 commencement, upon which the tendon of the tra- 

 pezius muscle moves; 12, acroinion; 13, one of the 

 nutrient foramina; 14, coracoid process. 



LEFT SCAPULA, ANTERIOR VIEW. 



1, ridges crossing the subscapular fossa ; 2, attach- 

 ment of the serratus muscle ; 3, superior border ; 4, 

 superior angle; 5, coracoid notch; 6, coracoid pro- 

 cess ; 7, acromion ; 8, spine of the scapula ; 9, artic- 

 ular surface for the clavicle ; 10, glenoid cavity ; 

 11, elevated margin of the same ; 12, neck ; 13, infe- 

 rior border; 14, inferior angle ; 15, base; 16, position 

 at which the spine commences. 



more dorsal, the inferior angle is at the lowest point, and the glenoid 

 cavity faces forward and outward. In form it is triangular, but the 

 long diameter is from the superior to the inferior angle, and the short 

 diameter from the head to the vertebral border. 



The external surface is posterior ; the supraspinous fossa is small, 

 and the iufraspinous fossa is large. 



The base of the spine is short ; its edge is flattened, and its outward 

 continuation, the acromion process, is curved, broad, and quadrate, 

 projecting far beyond the head. 



The superior border is relatively shorter, and as a rule the supra- 

 scapular notch is smaller and more distinctly marked. 



The bevelling on the axillary border at the expense of the dorsal 

 surface is more extensive, and is for the origin of the tere.s minor as 

 well as of the teres major muscle. 



The subscapular fossa is deepest along a line corresponding with 

 the attachment of the spine to the dorsal surface. 



