Cervical Spine

The atlas is the first of the seven cervical vertebrae, and is called such because it bears the direct weight of the skull, just as the mythical Greek hero Atlas bore the world on his shoulders. The atlas vertebra meets with the occipital condyles which flank the foramen magnum in the basilar part of the occipital bone of the skull. This junction forms the atlanto-occipital joint, and is responsible for the primary articulation between the spine and the skull. It is the only vertebra in the spine which has no vertebral body. The atlas vertebra, in turn rests upon the axis vertebra, which is the second of the cervical vertebra in the spine, with the articulation between these two vertebra occurring at lateral articular surfaces and an unique juncture between a concave facet (on the atlas) and an upward-protruding structure on the axis called a dens.

The axis is the second of the seven cervical vertebrae, and is called such because it allows axial (rotational) movement of the skull. The axis lies directly beneath the atlas vertebra, their junction occurring at lateral articular surfaces and an unique juncture between a concave facet (on the atlas) and an upward-protruding dens (on the axis). This articulation is regulated by the alar ligament, which attaches to both atlas and axis.