Also called: first cervical vertebra, C1
The atlas is the first cervical vertebra (C1). It is a ring-shaped bone with no vertebral body that supports the skull at the atlanto-occipital joints. It allows nodding of the head, while its articulation with the axis allows rotation.
| Type | Irregular bone (ring-shaped vertebra). |
|---|---|
| Location | Top of the vertebral column. |
| Landmarks | Anterior and posterior arches, lateral masses, superior and inferior articular facets, transverse processes, transverse foramina. |
| Articulations | Occipital condyles (atlanto-occipital joints) and axis (atlanto-axial joints). |
| Muscle attachments | Rectus capitis muscles, obliquus capitis muscles, levator scapulae, longus colli. |
3D model: BodyParts3D (CC BY 4.0), adult male reference anatomy. Highlighted structure shown with nearby bones for context.
The atlas lacks a body because the body of C1 fuses with the axis to become the dens (odontoid process).
It supports the skull, like the mythological Atlas who held up the sky.
Nodding, or flexion and extension of the head.
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