Upper Cervical Spine Biomechanics

Flexion/Extension
 The total range of flexion and extension of the upper cervical complex is approximately +23 degrees. The occipito-atlantal joint contributes a slightly greater amount of motion to the total range of flexion and extension. Click here to display a table that summarizes these findings.

During flexion and extension of the occiput upon the atlas, the occipital condyles slide back and forth on the lateral masses of the atlas, and the atlas rolls and slides on the superior facets of the axis (Click here to view this).

The maximum range of flexion is limited by tension developed in the articular capsules and the posterior ligaments and muscles. The maximum range of extension is limited by the approximation of the occiput, the posterior arch of the atlas, and the posterior process of the axis.
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