558 



MAMMALIAN ANATOMY 



FIG. 433. 



At Thirty Days. 



At Seventy Days. 



At One Hundred and 

 Thirteen Days. 



10 



POSTERIOR 

 ASPECT. 



ANTERIOR 

 ASPECT. 



PLAN OF THE DEVELOPMENT OF THE 

 HUMERUS FROM SEVEN CENTRES. 



(Natural size.) 



uppermost and the lower end toward 

 the student, the supracondyloid fora- 

 men will be on the side to which the 

 bone belongs. 



Articulation. The humerus 

 articulates with the scapula, the 

 radius, and the ulna. 



Muscular Attachments. The 

 following muscles are inserted on 

 the humerus : on the greater tuber- 

 osity, the supraspinatus, the ante- 

 rior part of the deep pectoral, the 

 infraspinatus, and the teres minor ; 

 on the lesser tuberosity, the sub- 

 scapularis ; on the anterior border, 

 the posterior^, part of the deep pec- 

 toral, the middle pectoral, the ante- 

 rior part of the middle pectoral, the 

 superficial pectoral; on the deltoid 

 ridge, the outer humeral head of the 

 triceps ; on the external surface and 

 deltoid ridge, the deltoid; on the 

 anterior border and the external 

 surface, the anterior part of the 

 middle pectoral; on the internal 

 surface, the teres major and the 

 latissimus dorsi; on the internal 

 border, the coraco-brachialis and 

 the supracoudyloid head of the 

 triceps. 



The following muscles arise from 

 the humerus : on the external and 

 posterior surfaces, the posterior 

 humeral head of the triceps ; on 

 the external surface, the brachialis 

 anticus ; on the posterior surface, 

 the inner humeral head of the 

 triceps and the anconeus ; on the 



