Second cervical vertebral body (Axis)
The First and Second cervical vertebral bodies are unique in their shape and function. The more commonly-used term for the Second cervical vertebral body is the Axis, and is also designated C2 (Cervical 2). This bone forms a joint with the Atlas (C1, First cervical vertebral body) at the complex C1-C2 articulation.
The vertebral arteries take a complex course at the craniocervical junction where they course laterally through the Axis and then pass through the transverse foramina of the Atlas (First cervical vertebral body).