THE HUMERUS. 



Ill 



behind the glerioid cavity the bone is constricted, forming 

 the neck, to which is attached the capsular ligament. 

 The base is the strongest part of the bone, and, owing to 

 the large quantity of cancellous tissue here present, it is 

 commonly the first part invaded by diseases affecting this 

 bone. 



The scapula develops 

 by six centres, one for 

 the base, one for the 

 coracoid process, two for 

 the acromion, one for the 

 inferior angle, and one 

 for the posterior surface 

 and vertebral border. 



The humems be- 

 longs to the class of long 

 bones. It is the longest 

 and largest bone of the 

 upper extremity, and 

 presents for examina- 

 tion a shaft and two 

 extremities. The upper 

 extremity preseiits__.,a 

 scanty" hemispherical 

 head, which articulates 

 with the glen o id cavity 

 of the scapulaj behind 

 the head is a slight constriction, the anatomical neck, to 

 which is attached the capsular ligament. External to 

 the neck, on the anterior surface, are two blunt eleva- 

 tioiis^pf bone, the greater, or outer, and the lesser, or 

 inner, tuberosities, separated by a deep groove, which 



FIG. 52. THE HUMERUS, ANTERIOR 

 SURFACE. 



