Atlanto-Occipital Joints

articulationes atlantooccipitales

The atlanto-occipital joints are the paired synovial joints between the occipital condyles (oval convex articular surfaces on the inferior occiput) and the superior articular facets of the atlas (concave kidney-shaped surfaces on the C1 lateral masses). They allow the primary nodding motion of the head (flexion-extension) and slight lateral bending. Rotation is minimal at C0-C1 — rotation occurs predominantly at C1-C2.

Region: Neck

Clinical Relevance

Clinical Notes

The atlanto-occipital joints are affected in rheumatoid arthritis (forming part of the craniovertebral junction instability pattern), Chiari malformation, and Down syndrome. Atlanto-occipital assimilation (occipitalisation of the atlas) is a congenital fusion that eliminates the C0-C1 joint and creates abnormal compensatory motion at C1-C2. In occipitocervical fusion for craniovertebral instability, the joints are decorticated and fused with bone graft in addition to rigid plate fixation. Joint injections target the posterior approach to the joint with fluoroscopic or CT guidance.

Pathology

Common Injuries & Conditions

Atlanto-Occipital Dislocation

High-energy trauma completely disrupts the atlanto-occipital joint capsule and all supporting ligaments, producing atlanto-occipital dislocation with usually fatal craniovertebral junction injury; survivors require emergent occipitocervical fusion as any reduction attempt risks catastrophic brainstem injury from the unstable craniovertebral junction.