Diameters and bone thickness at the margin of the foramen magnum in dry skulls from pediatric population: a cross-sectional anatomical study.

ABSTRACT

PURPOSE: The purpose of the study was to estimate the size and bone thickness at the margin of the foramen magnum in a pediatric population. METHODS: Sixty occipital bone specimens from the collection of macerated skulls at the Department of Anatomy, University of Zagreb, were examined and measured using a vernier scale/caliper. For the purpose of analysis, specimens were divided into two age groups 1-6 years and 7-18 years of age (before and after the fusion of ossification centers in the occipital bone). We measured the following antero-posterior and transverse diameters of the foramen magnum, bone thicknesses at the basion, opisthion, two paramedial points on the anterior and posterior margins, and at the occipito-squamous junction. RESULTS: Data presented in this study show that diameters of the foramen magnum increase with age, whereas bone thickness shows variable behavior depending on the measured area. CONCLUSIONS: Increases in diameters in specimens from the younger age group and their absence in specimens from older subjects reflect the growth pattern of the basilar part of occipital bone. Variability of bone thickness at the margin of the foramen magnum and lack of its association with age of the subjects may be attributed to various factors and may potentially affect the clinical presentation of compression syndromes at the level of foramen magnum.