SEXUAL DIMORPHISM IN THE FORAMEN MAGNUM: NEW DATA, SYSTEMATIC REVIEW, AND META-ANALYSIS

E. D. Fernández, J. M. González, J. P. Frutos, E. R. Tagle, M. C. Rodríguez, M. G. Serradilla, D. C. Monllor

Abstract:
The foramen magnum is very interesting from a forensic context to estimate sex in individuals due to the robusticity of the cranium. The objectives of this study were to determine how the length and width of the foramen magnum differs between sexes, compare our data with previously published results, and compare classical calliper and tomography measurements. The sample comprised 107 crania belonging to a Spanish population available at the Complutense University of Madrid. Two types of measurements were assessed: conventional calliper (length and width) and tomography image analysis (height and width). A systematic review with 44 studies was performed, and meta-analyses were performed based on classification by measurement techniques and ethnic origin. The measurements related to width had the highest percentage of correct assignation of sexes ranging between 70.4–100% for males and 58.1–73.6 % for females. Length showed 81.5% accuracy for males and 60.0% for females, while height presented 81.2% for males and an interval of 62.7 to 69.8% for females. Length and width of measurements showed that there were statistically significant differences between males and females in both calliper and image methods. The assessment of ethnic origin did show a statistical difference in length and width. When the different studies were distributed between techniques, statistically significant differences were found for width but not height; thus, the measurement technique could influence the results.
Keywords: forensic anthropology, foramen magnum, sexual dimorphism, ethnic origin, meta-analysis.