VERTEBRAL COLUMN 



103 



The cephalic surface (Fig. 74) is a third wider than the caudal 

 surface and at least twice as high. Its middle is occupied mainly by 

 the prominent, flat, and oblong surface which joins the body of the 

 seventh lumbar. On each side of this surface is the triangular 



FIG. 74. 



Cephalic Articular Surface. 



Cephalic Articular Process. 

 Pedicle. 



Lateral Mass. 



THE SACRUM, ANTERIOR OR CEPHALIC VIEW. 



cephalic surface of the lateral mass, convex from the dorsal to the 

 ventral edge, and sloping laterally and toward the head. 



Each lateral surface (Fig. 75) consists of two parts of nearly equal 

 cephalo-caudal length. Of these, the cephalic half is the side of the 

 lateral mass contributed by the transverse process of the first sacral 

 vertebra. It is almost as high as it is long ; pear-shaped, large at the 



FIG. 75. 



Sacral Neural' Spines. 



'^ 



/ 



Cephalic Articular Process. 

 United Articular Processes. 



Rough Space for Ligaments. 



Auricular Surface, 

 with Ilium. 



Caudal Articular Surface. 

 Intervertebral Notch. 



Body of Third Sacral Vertebra, 

 with Body of First Caudal. 



THE SACRUM, SIDE VIEW. 



cephalic and narrow at the caudal part. Its arched ventral margin is 

 sharp. Its dorsal margin is divided from the dorsal surface of the 

 sacrum by an arcuate, elevated line, which is crossed obliquely from 

 the caudal end, ventrally and toward the head, by a groove, leading 

 from the first dorsal sacral foramen. The surface is, in general, flat, 



