OSTEOLOGY. 49 



Subscapular angle, a transverse depression at the upper part 

 for the thickest part of the muscle. 



The posterior surface, or dorsum, presents: 



Spine, a bony ridge passing upward, forward, and outward, 

 dividing it unequally into two fossa?, affording attachment to 

 the trapezius muscle above and the deltoid below, and terminat- 

 ing above in the acromion process; 



Supra-spinous fossa above the spine, for the origin of the 

 supra-spinatus muscle; 



Infra-spinous fossa below, for the origin of the infra-spina- 

 tus muscle; 



4 2 



FIG. 20. 



1, 1, 1, oblique ridges; 3, superior border; 4, superior angle; 5, 

 supra-scapular notch; 6, coracoid process; 7, acromial process; 10, 

 glenoid fossa; 14, inferior angle. 



Nutrient foramen, near the upper part of infra-spinous 

 fossa, for nutrient artery. 



The marginal surface extends from the glenoid cavity down- 

 ward and backward to an inch above inferior angle, its inner 

 side formed by 



An elevated ridge, for the attachment of the aponeurosis 

 between the inf ra-spinatus and two teres muscles ; its outer side 

 by the axillary border. It is divided by an oblique line into two 

 parts, the upper for the teres minor and the lower for the teres 

 major muscles, and crossed by a groove near the upper part for 

 the dorsalis scapulae vessels; 



A smooth, triangular surface at the root of the spine over 

 which the trapezius glides. 



