Morphometric Analysis of the Foramen Magnum

The foramen magnum is morphometrically typified by two perpendicular diameters and a distinct margin. This important anatomical landmark is subject to high interindividual variation. The objective of this study was to evaluate the dimensions and morphology of the foramen magnum in a Jordanian population. In this retrospective study, 247 individuals were consecutively sampled using the institutional picture archiving and communication system. The anteroposterior and transverse diameters of the foramen magnum were measured; the foramen magnum index was calculated; and, the shape of the foramen magnum was visually assessed. The sex-pooled anteroposterior and transverse diameters were 35.1 ± 3.2 mm and 29.3 ± 2.5 mm, respectively. The sex-pooled foramen magnum index was 1.20 ± 0.10. The diameters were significantly different (P