VEETEBEAL COLUMN 65 



nerve. Caudal to the foramen and groove, the dorsal surface slopes 

 ventrally and becomes continuous with the dorsal surface of the trans- 

 verse process. The caudal margin of the arch is thin and deeply 

 emarginate. Its prominent lateral ends are continued ventrally into 

 the arcuate caudal edge of the caudal articular process. 



The transverse processes are thin, ear-shaped plates directed 

 laterally from the sides of the ventral part of the arch. The cephalo- 

 cauclal diameter of each process is shorter at the root than at the lateral 

 edge. The dorsal surface (Fig. 39) is excavated for the attachment of 

 the obliquus capitis inferior muscle. Its caudal margin is arched 

 transversely and pierced close to the neural arch by the arterial canal. 

 This canal does not extend through the entire length of the process, 

 but appears again on the ventral aspect cephalic to the middle, and is 

 continued as the groove already mentioned. The medial wall of the 

 canal is pierced at the cephalic end by a foramen, which leads into the 

 neural canal and transmits a vessel. The ventral surface of the trans- 

 verse process (Fig. 38) is smooth and almost flat. It gives attachment 

 to the following muscles : on the cephalic two-thirds, to the obliquus 

 capitis superior ; on the caudal third, to the rectus capitis lateralis and 

 levator claviculre ; on a small triangular area just medial and caudal to 

 the cephalic opening of the arterial canal, to the rectus anticus minor. 



FIG. 40. 



Neural Arch. 



Canal for Vessels. 



Transverse 

 Process. 



Body. 

 THE ATLAS, POSTERIOR OR CAUDAL ASPECT. 



The caudal articular processes are not distinct (Fig. 40). Each 

 is that expanded median part of the caudal edge of the transverse 

 process which is directed to face medially and toward the tail. The 

 articular surface is slightly concave, and encroaches on the caudal 

 margin of the so-called body. 



Each cephalic articular process (Fig. 41) is thin, laterally strongly 

 convex and medially deeply concave from the dorsal to the ventral 



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