Atlanto-Occipital Joint (AOJ)

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Use of this artwork requires proper credit to be given (Permission: Dr. Joe Muscolino. www.learnmuscles.com – photography by David Eliot)

The atlanto-occipital joint (AOJ) is actually composed of two facet joints (paired, left and right) between the atlas (C1) and the occiput.
More specifically, it is located between the superior articular facets of the atlas and the occipital condyles.
Facet joints are synovial joints that allow motion in all three cardinal planes.
The atlanto-occipital joint allows:
- flexion/extension of the head in the sagittal plane.
- right lateral flexion / left lateral flexion of the head in the frontal plane.
- right rotation / left rotation of the head in the transverse plane.

NOTES:

Sagittal-plane extension is the greatest range of motion of the head at the atlanto-occipital joint.
Because the atlas has no body, there is no disc joint between the atlas and the occiput.
The head can also protract and retract at the atlanto-occipital joint. Excessive protraction of the head is a postural distortion pattern known as forward head posture or forward head carriage, which is a part of a larger postural distortion pattern known as upper crossed syndrome.

Posterior view of the atlanto-occipital joint between the atlas (C1) and the occiput.

Right lateral view of the atlanto-occipital joint between the atlas (C1) and the occiput.