In vitro characterization of the anterior to posterior curvature of the superior articular facets of the atlas as a function of age.

Background Context: Reference is made in the literature to the inherent instability of the atlantooccipital joint in infants and young children because of pliant ligaments, undeveloped musculature, smaller condyles, and the relative lack of anteroposterior curvature of the superior articular facet surfaces of the atlas. The combination of these morphologic factors is purported to make this population particularly vulnerable to whiplash-type injuries. Although a significant difference in the magnitude of the anteroposterior curvature of the superior articular facet surfaces of the atlas between young children and adults has been observed, quantitative analysis of the curvature of these surfaces has not been documented.