Axis (C2)

Bones

Open in 3D

In anatomy, the axis (from Latin axis, "axle") or epistropheus, is the second cervical vertebra (C2) of the spine, immediately posterior to the atlas, upon which the head rests.

The axis' defining feature is its strong odontoid process (bony protrusion) known as the dens, which rises dorsally from the rest of the bone.

Definition from Wikipedia, CC BY-SA 4.0.