80 OSTEOLOGY, OR ANATOMY OF OSSEOUS SYSTEM 



for intermuscular septa of the infraspinatus muscle, which 

 rises from the inner two-thirds and covers the outer third. 

 Along the outer part of this surface is a ridge passing down 

 and back to the inner border, about 1 inch above the inferior 

 angle; it gives attachment to the aponeurosis between the 

 infraspinatus and teres muscles. On the upper third of the 

 narrow surface between this line and the axillary border is 

 a groove for the dorsalis scapulae vessels; the middle third and 

 part of the upper give attachment to the teres minor. Below 

 this, including the inferior angle, is a raised surface for the 

 teres major, over which the latissimus dorsi glides or attaches 

 a small fasciculus. An oblique line separates the origins of the 

 two teres muscles. 



The spine of the scapula is a triangular plate projecting 

 back and up from the dorsum. Beginning near the upper 

 fourth of the vertebral border, it passes out. across the dorsum 

 to the middle of the neck of the scapula, and turns forward 

 into the acromion process. The upper and lower surfaces 

 are concave and form parts of the two dorsal fossae. It has two 

 unattached borders, a posterior subcutaneous one and an 

 external axillary one. The former rises from the vertebral 

 border by a triangular surface, over which a tendon of the 

 trapezius glides as it passes to its insertion into a rough tubercle 

 beyond. The rest of this border is rough and serpent ine, and 

 gives attachment by a superior lip to the trapezius, by an infe- 

 rior lip to the deltoid. The external border is short, smooth, 

 and concave, enclosing the great scapular notch. 



The acromion process projects out and forward over the glen- 

 oid fossa; it is compressed from above down; its superior surface 

 is rough, subcutaneous, and continuous with the prominent 

 border of the spine. Anteriorly, on its inner border, is an oval 

 articular facet for the clavicle; to this border is attached the 

 trapezius, to the outer border the deltoid, marked by three or 

 four tubercles for tendinous septa. This outer border terminates 

 posteriorly in the acromial angle. The coracoacromial liga- 

 ment is attached to the apex of the acromion. 



The coracoid process rises at first almost vertically from the 

 upper border of the head, compressed from before backward; 

 it then bends at a right angle forward and outward, and is 

 compressed from above downward. Superiorly, toward its 

 base, is the origin of the conoid ligament, and the trapezoid 



