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) to these there is a secondary center for a thin epiphysial plate on the under surface of the body of the bone. Fractures of the dens, not to be confused with Hangman's fractures, are classified into three categories according to the Anderson–D'Alonso system: Axis (anatomy) In anatomy, the second cervical vertebra (C2) of the spine is named the axis (from Latin "axis", "axle") or epistropheus. By the atlanto-axial joint, it forms the pivot upon which the first cervical vertebra (the atlas), which carries the head, rotates. The most distinctive characteristic of this bone is the strong odontoid process known as