The second cervical vertebra (Axis; C2) is the pivot for rotation of head and atlas (C1), so it differs from other cervical vertebrae by:
- a cylindrical body with a well marked ventral crest
- the dens at the cranial extremity of the body.
The dens of axis may be considered as the displaced remnant of the body of atlas. The dens articulates with the ventral arch of atlas and presents:
- An apex (cranial extremity)
- A ventral articular surface for articulation with the fovea dentis on the dorsal surface of the ventral arch of the atlas. This surface is confluent with the cranial articular surfaces in horse and ox but separate in other domestic animals.
- A dorsal articular surface in carnivores and pigs.
Illustrated Veterinary Anatomical Nomenclature - 3rd edittion - Gheorghe M. Constantinescu, Oskar Schaller - Enke