Morphological parameters of the superior articular facets of the atlas and potential clinical significance

Abstract

Although remarkable investigations exist in regard to the morphology of the superior articular facets of the atlas in the literature, only a few data exist concerning the correlation of these facets with the age of the specimens. The superior articular facets of the atlas were studied in 86 dried vertebrae. Several non-metric parameters were recorded, like presence of notches, grooves, complete or partial dissociation, rough surfaces as well as their morphology. No notch was found in 37.2% of the superior articular facets. The incidence of notch is decreased as the age progresses. No transverse groove was found in 24.4% and the presence is increased with the age. The incidence of complete and partial dissociations was also found to be age-related. The incidence of rough surfaces, which corresponds to the site of maximum weight bear, was found to be increased in the old age. We classified the shape of the facets into the following types: oval-shaped, kidney-shaped, S-like, triangle, circular and two portioned. We assume that the increase of incidence of the dissociation, the rough surfaces, the grooves and the decrease of notches could be possibly the result of a restriction of the atlanto-occipital motion in the old age.