THE MARGINS AND ANGLES OF THE SCAPULA. 153 



line of the scapula may be characterized as either subtriangular or 

 approximately semicircular. The former term is more commonly 

 employed, perhaps because it is more applicable to the human 

 scapula. But if the two scapulae of the cat are placed with their 

 straighter sides in apposition, they will be seen to cover an area 

 which is approximately circular, although the borders are more or 

 less undulating. 



§ 383. The Margins and Angles of tJie Scapula. — It is at least 

 convenient to regard the scapula as triangular, and as presenting 

 therefore three sides (margines) and three angles (anguli). 



The thicker (glenoid or arthral) angle articulates with the hu- 

 merus, and presents several elevations and depressions which will 

 be described separately. Its larger part is occupied by a concave 

 surface, the Fossa glenoidea, for articulation with the humerus; 

 hence that border of the bone which is separated from the fossa only 

 by its lip is called the Margo glenoideus. Between the fossa and 

 the other border springs a hook-shaped projection, the Pre. cora- 

 coideus, and the border is thence named Mrg. coracoideus. The 

 intermediate border is called the Mrg. vertebralis from its proxim- 

 ity to the Columna nertedralis. 



Of the borders, the glenoid is the longest and straightest. The 

 coracoid is the shortest and least regular, and its outline varies in 

 different individuals. According to the observations of Parker (A, 

 216, PL XXX., Fig. 1-3), in the cat and in some other Carnivora this 

 margin ossifies from an independent center and remains for some 

 time separate from the rest of the bone. The vertebral border is 

 intermediate in length, and presents a nearly regular curvature. 

 With young individuals this margin is cartilaginous, representing a 

 suprascapula, but later it becomes coossified with the rest. 



The angles, respectively more and less obtuse, formed by the 

 junction of the vertebral margin with the other two, are called coraco- 

 vertebral and gleno-verteiral. 



The emargination of the coracoid border near the neck of the 

 bone (at the lower end of the dotted space in Fig. 43) is known as 

 the Incisura coraco-scapularis (Flower, A, 223). In the human 

 scapula it is deeper and commonly called the suprascapular notch. 



§ 384. Description of Fig. 43. — The ental aspect of an adult left scapula. 

 Acromion. — TMs is more distinctly seen in Fig. 44 and 45. 



§ 385. Arem Muaculares— kreas of tbe attachment of muscles. — Upon these two fig- 

 ures of the scapula and upon four views of the humerus (Fig. 68-71), the areas of muscular 



