Morphology and morphometry of the foramen magnum: a systematic review and meta-analysis of anatomical studies

This meta-analysis aimed to synthesize available data on the morphology and morphometry of the foramen magnum (FM), identifying population and sexual patterns. Conducted in accordance with PRISMA and Cochrane guidelines, the study included observational research providing FM morphological and morphometric data from cadaveric dissection or imaging in human populations. A search of PubMed, Web of Science, and Scopus yielded 562 records; after screening, 19 articles comprising 3,432 individuals from five continents were selected. Pooled analysis using random-effects models revealed overall adult mean values of 29.458 mm (transverse diameter), 35.217 mm (anteroposterior diameter), and 853.975 mm² (area). Males exhibited larger dimensions than females, though with considerable overlap. Morphological analysis demonstrated predominance of hexagonal (16.8%), pear-shaped (16.4%), and oval (15.8%) configurations. Significant heterogeneity (p<0.01) was identified across studies, reflecting methodological and population differences. Findings indicate that while FM dimensions show relative consistency, significant population and sex-related variations exist, precluding universal anatomical standards. The morphological expression did not differ substantially between sexes. This study reinforces the FM's relevance in clinical, surgical, and forensic contexts, particularly for craniocervical approach planning and pathological understanding. Methodological heterogeneity and regional variability necessitate population-specific databases for accurate diagnostic and identification procedures, highlighting the need for standardized future research with diverse population samples. Mini-abstract This meta-analysis synthesizes foramen magnum morphometric data from 3,432 individuals across five continents, revealing population-specific dimensions and predominance of hexagonal, oval, and pear-shaped configurations