Functional Role of the Superior Articular Facets of the Atlas in the Enhancement of Craniovertebral Junction Stability

Whiplash distortions of the cervical spine, occurring during the retraction phase of a rear end automobile accident, are known to cause posterior translation of the head relative to the chest and shoulders [1,2]. This anteroposterior shear produces sagittal plane rotation of the cervical spine which results in relative flexion between the occiput and the atlas (Fig. 1). This study demonstrates that there is a significant difference between the average angles of the anterior aspects and the posterior aspects of the superior facets of the atlas with respect to a horizontal (transverse) plane at P