54 



ELEMENTS OF MAMMALIAN ANATOMY. 



mata, where it articulates at one end with the scapula, 

 forming part of the glenoid cavity, and at the other end 

 with the presternum. In the other 

 mammals the coracoid is represented 

 by the coracoid process of the scapula, 

 which ossifies from a separate center. 

 In many of the lower vertebrates a dis- 

 tinct coracoid is present. 



The humerus is the bone of the 

 arm or brachium. It articulates prox- 

 imally with the glenoid cavity of the 

 scapula (Fig. 21) and distally with 

 the ulna and radius. It consists of 

 three parts : the proximal extremity 

 bearing the head, the middle portion 

 or shaft, and the distal extremity (Fig. 

 32). The greater and lesser tubcr- 

 osities separated by the bicipital groove 

 lodging the tendon of the biceps 'mus- 

 cle, are the two processes on the proxi- 

 mal extremity. The former is the 

 larger and more craniad and serves for 

 the insertion of the supraspinatus mus- 

 cle (Fig. 49). The distal extremity is 

 marked by two important projections, 

 the external and internal condyles. 

 Extending proximad from the external 

 condyle is the supinator ridge. Proxi- 

 mad of the internal condyle is the 

 supracondyloid foramen transmitting 



FIG. 32. CRANIAL AS- 

 PECT OF RIGHT HU- 

 MERUS. 



bl, Bicipital groove ; 

 cr, supracondyloid 

 ridge ; cp, capitel- 

 lum for articulation 

 with the radius ; dr, 

 deltoid ridge ; et, 

 external condyle ; 

 gt, greater ^ tuber- 

 osity ; it, internal 

 condyle ; It, lesser 

 tuberosity; sp, su- 

 pracondyloid fora- 

 men or entepicon- 



su y pinat f or ra rTdg n e ; ; the median nervp. and brachial artery 

 (Figs. $ and -89). The olecranon 

 fossa is the deep cavity on the caudal 

 aspect of the bone, opposite the coronoid fossa. The articu- 



trochlea for artic- 

 ulation with ulna. 



