Bone
Axis (C2)
Second neck vertebra providing the dens for head rotation
High-yield
The dens and the pars interarticularis are different parts of C2. An odontoid fracture breaks the dens; a typical hangman's injury breaks the bony bridges between the upper and lower articular regions on both sides.
Overview
The axis supports C1 and projects its dens upward into the atlas ring. The atlas and skull turn together around this central pivot, while paired lateral joints share movement and support.
Reference facts
- Bone type
- Irregular bone of the cervical spine
- Key landmarks
- Dens (odontoid process); usually forked spinous process; paired superior articular surfaces; pars interarticularis
- Articulations
- Atlas at median and paired lateral atlanto-axial joints; C3 through a disc and paired facet joints
Clinical correlation
A hangman's fracture commonly follows hyperextension with axial loading, although other mechanisms occur. Stability depends partly on associated C2–C3 disc and ligament injury, so the fracture name alone does not describe its severity.
Frequently asked questions
What type of bone is the axis (C2)?
The axis (C2) is an irregular bone of the cervical spine bone.
What does the axis (C2) articulate with?
Atlas at median and paired lateral atlanto-axial joints; C3 through a disc and paired facet joints.
What are the key landmarks of the axis (C2)?
Dens (odontoid process); usually forked spinous process; paired superior articular surfaces; pars interarticularis.