SO HANDBOOK OF ANATOMY 



teriorly. Above, the margin is projecting, forming the promon* 

 tory of the sacrum. This is more marked in the male than the 

 female. 



The posterior surface is convex from above downwards, and 



Superior Articular Process 



Ala 



Inferior Lateral Angle 



4th Anterior Sacral Foramen 



FIG. 26. SACRUM (ANTERIOH SURFACE). 



has the four foramina on each side, similar to the anterior 

 surface. In the middle line the spines of the vertebrae still 

 persist as four tubercles. 



On each side of the upper part of the bone are the lateral 

 masses, large stout masses of bone, on the external aspects of 

 which are the surfaces for articulation with the innominate 

 bone. 



