Transverse ligament of atlas former is attached to the basilar part of the occipital bone, in close relation with the membrana tectoria; the latter is fixed to the posterior surface of the body of the axis; hence, the whole ligament is named the cruciate ligament of the atlas. The transverse ligament divides the ring of the atlas into two unequal parts: of these, the posterior and larger serves for the transmission of the medulla spinalis and its membranes and the accessory nerves; the anterior and smaller contains the odontoid process. The neck of the odontoid process is constricted where it is embraced posteriorly by
Axis (anatomy) vertebrae The spinous process is large, very strong, deeply channelled on its under surface, and presents a bifurcated extremity. Contact sports are contraindicated for individuals with an anomalous dens, as any violent impact may result in a catastrophic injury. This is because a malformed odontoid process may lead to instability between the atlas and axis (the C1 and C2 cervical vertebrae). The axis is ossified from five primary and two secondary centers. The body and vertebral arch are ossified in the same manner as the corresponding parts in the other vertebrae, viz., one center for the body, and two for