Axis (C2; Second cervical vertebral body)
The First and Second cervical vertebral bodies are unique in their shape and function. The Axis is the Second cervical vertebral body, 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 Second cervical vertebral body (also called the Axis) and then pass through the transverse foramina of the Atlas (First cervical vertebral body).