The drawing of a cervical vertebra in Fig. 9 would represent, with minor modifications, the general appearance of any member of this series from the third to the sixth inclusive ; but the type has been distinctly altered in the upper and lower vertebrae of the region.

In the first two vertebrae the alteration is remarkable, in association with the necessity for providing free movement of the head on the column, but it is slighter in the seventh segment and connected with the change from the physical conditions of the cervical to those of the dorsal region.

The first vertebra is termed the Atlas, because it supports the globe of the skull: the second is called the Axis, because it forms the pivot round which the atlas turns and carries the skull.