OSSEOUS SYSTEM OF MAMMALIA. 



59 



superior oblique processes of the vertebra next succeeding. On the inner 

 aspect of the body is a smooth surface, to which is fitted a process 



44 



45 



Figs. 44 to 48. Atlas, in different aspects. 



Fig. 44, Superior. 45, Inferior. 46, Anterior. 47, Lateral. 48, Posterior.-a, the body of the atlas ; b, its posterior 

 arch ; c, the small spinous process ; d, rf, the articulating- cavity of the superior oblique processes, for the reception of the 

 condyles of the occipital bone ; e, the smooth inner surface, for the reception of the odontoid process of the axis ; /, f, the 

 inferior oblique processes, or articulating surfaces, by which the atlas is united to the superior oblique processes of the 

 axis ; g-, g, the cervical foramina; h, A, the transverse processes. (The same letters refer to the same part in all the above 

 figures- ) 



(termed odontoid, or tooth-like) arising from the next vertebra, called 

 the axis, or vertebra dentata (figs. 49, 50, 51, 52). The transverse pro- 

 cesses are simple, and larger than those of the other cervical vertebrae. The 

 odontoid process, which constitutes the main distinguishing feature be- 

 tween the second vertebra and the remaining five of the neck, arises from 

 the upper surface of the body of the bone, and proceeds upward within 

 the narrow body of the atlas, where it is firmly secured by ligaments, so 

 contrived as to prevent its slipping, or pressing against the medulla spin- 



50 



Figs. 49 to 52. Axis, in different aspects. 



Fig. 49, Superior view. 50, Inferior. 51, Anterior. 52, Lateral. a, odontoid process arising from the body of the bone > 

 fr, spinous process; c,c, the oblique processes, superior and inferior; d, d, the transverse processes. (The same letters refer 

 to the same part in all the above figures.) 



alis, while the atlas revolves upon it as a kind of axis. The motion 

 allowed to the head, by the articulation of the skull upon the first cervical 



