142 



THE SKELETON 



the spine is the infraspinous fossa ; it is three times as large as the supraspinous 

 fossa, is alternately concave and convex, and gives origin to the infraspinatus. 

 The muscle is attached to its medial three-fourths and covers the lateral fourth, 

 without taking origin from it. 



The infraspinous fossa does not extend as far as the axillary border, but is limited laterally 

 by a ridge — the oblique line — Which runs from the glenoid cavity — the large articular surface 

 for the head of the humerus — downward and backward to join the posterior border a short dis- 

 tance above the inferior angle. This line, which gives attachment to a stout aponeurosis, cuts 

 off an elongated surface, narrow above for the origin of the teres minor, and crossed near its 

 middle by a groove for the circumflex (dorsal) artery of the scapula; below, the surface is broader 

 for the origin of the teres major and occasionally a few fibres of the latissimus dorsi. The two 

 areas are separated by a line which gives attachment to an aponeurotic septum situated 

 between the two teres muscles. 



Fig. 171. — The Left Scapula. (Dorsal surface.) 



Coraco-acromial ligament Omo-hyoid and the superior transverse ligament 



Superior angle 



Neck of scapula and 

 scapular notch 



Articular capsule 



Glenoid fossa 



Groove for circumflex artery of 

 the scapula 



Rhomboideus 

 minor 



Axillary border- 



Teres major 



Willi Rhomboideus 

 major 



ertebral 

 border 



Inferior angle 



Latissimus dorsi 



Tlic sui)ra- and infraspinous fossae communicate through the great scapular 

 notch at the lateral border of the spine, and through the notch the suprascapular 

 iiorvc and transverse scapular artery are transmitted from one fossa to the other. 



Borders. — The three borders of the scapula arc named superior, vertebral, 

 and axillary. The superior is short and thin and extends from the upper angle 

 to the coracoid process. Laterally it presents a deep depression, the scapular 

 notch, to the extremities of which" the superior transverse ligament is attached. 



Not infrefjiioiitly the notch is rciilaced l)y a scapular foramen, and it is interesting to note 

 that a bony foramen occurs normally in some animals, notably the great ant-eater {Myrmeco- 

 phaga jubula). The notch or foramen transmits the suprascapular nerve, whilst the transverse 

 scapular artery usually pa.sses over the ligament. From the adjacent margins of the notch and 

 from the ligament the posterior belly of the omu-hyoid takes origin. 



I 



