DISSECTING MANUAL. 



bral) border, the longest, connects the superior and inferior 

 angles and is curved ; it presents a narrow surface for muscular 

 attachments. The external (axillary) border, connecting the 

 external and inferior angles, is the stoutest; its upper inch is 

 rough and usually limited below by a groove for the dorsalis 

 scapulae artery. The superior angle is sharp and rather rect- 

 angular; the inferior is blunter and more acute. The external 

 angle (head) has a pyriform and slightly concave facet (glenoid 

 surface) with a slightly raised edge, for the humerus; this edge 

 is confluent below with an impression (infraglenoid) , and 

 blends above with a tubercle (supraglenoid). A constricted 

 portion (neck), corresponding to a line between the suprascap- 

 ular notch and infraglenoid tubercle, supports the head. The 

 coracoid process springs from the whole upper part of the head 

 in line with the superior border; it runs upward, then bends 

 nearly at right angles, and ends in a process running outward 

 and slightly forward over the glenoid fossa. [186] 



The spine is a triangular process on the dorsal surface; it 

 divides this surface into the supraspinous and infraspinous 

 fossae. One border is attached in a line running, from near the 

 lower limit of the upper fourth of the vertebral border, toward 

 the centre of the posterior glenoid edge; it is separated from 

 this edge by a notch (great scapular). The surfaces of the 

 spine are concave, look upward and downward, and enter into 

 the fossae. Its external border is free and concave. Its free 

 posterior border has two strongly lipped edges, upper and 

 lower, and an intervening space which is triangular at the inner 

 end but narrow elsewhere. This posterior border is prolonged 

 as a flattened plate (acromion process), which bends sharply 

 (acromial angle) and curves forward, upward, and outward over 

 the glenoid fossa. The under surface of the acromion process 

 is smooth but the upper is rough ; on the internal border, near 

 the tip, is a facet for the clavicle. [187] 



The supraspinous fossa, the smaller and upper, communi- 

 cates with the infraspinous fossa at the great scapular notch; 



[142] 



