- The axis is the second cervical vertebra (C2).
- The axis articulates with:
- the atlas (C1) above, forming the atlanto-axial joint.
- C3 below, forming the C2-C3 joint complex via the paired facet joints and the disc joint.
NOTES:
- What would have been the body of the atlas (C1 above) fused onto the axis instead, creating the odontoid process, aka the dens.
- The dens creates a vertical axis of motion that the ring-shaped atlas can rotate around (left and right rotation in the transverse plane). The atlanto-axial joint between the atlas and axis is responsible for 45% of all cervicocranial rotation.
- The axis has the largest spinous process in the cervical spine.
![Posterior view of the axis (C2).](https://learnmuscles.com/wp-content/uploads/2017/04/11-C2-posterior-0256-0257-1024x1024.jpg)
Posterior view of the axis (C2).
![Anterior view of the axis (C2).](https://learnmuscles.com/wp-content/uploads/2017/04/11-C2-anterior-7022-modified-1024x836.jpg)
Anterior view of the axis (C2).
![Right lateral view of the axis (C2).](https://learnmuscles.com/wp-content/uploads/2017/04/11-C2-lateral-7028-1024x829.jpg)
Right lateral view of the axis (C2).
![Superior view of the axis (C2).](https://learnmuscles.com/wp-content/uploads/2017/04/11-C2-superior-7034-1024x1024.jpg)
Superior view of the axis (C2).
![Inferior view of the axis (C2).](https://learnmuscles.com/wp-content/uploads/2017/04/11-C2-inferior-7040-1024x1014.jpg)
Inferior view of the axis (C2).