Morphometric Analysis of Foramen Magnum and Occipital Condyles for Sexual Dimorphism: Exploring Reliability Through Computed Tomography Investigation

Abstract

Anatomical differences between males and females, has been of significant interest in various scientific fields. This study aims to investigate sexual dimorphism in North Indian population by analyzing the dimensions of the foramen magnum, a critical opening at the base of the skull and occipital condyles utilizing computed tomography (CT) imaging. Furthermore, variations in the shape of the foramen magnum are noted and classified into seven distinct types. CT scans of 299 individuals aged between 18 and 87 years underwent precise measurements of the foramen magnum dimensions. Eleven parameters were scrutinized, including foramen magnum length, width, the length and width of the right and left occipital condyles, minimum and maximum intercondylar distance, foramen magnum index, and foramen magnum area calculated using both the Teixeira and Radinsky formulas. Intraobserver and interobserver tests were conducted to assess measurement reliability. Statistical analyses were applied to investigate potential variations in these measurements based on sex. With the exception of the minimum intercondylar distance, all measurements were significantly greater in males. The most common shape of the foramen magnum was oval, while the least common was the pentagonal shape. However, it was found that the shape of the foramen magnum was not a reliable parameter for determining sex. Sexing accuracy, calculated through binary logistic regression and ROC curve analysis, indicated an accuracy of 68.2% for foramen magnum length (FML), 65.8% for foramen magnum width (FMW), and 75.2% and 74.9% accuracy for foramen magnum area when calculated using the Teixeira and Radinsky formulas, respectively, signifying their reliability in distinguishing gender. A multivariate analysis incorporating all eleven parameters demonstrated an overall accuracy of 73.6%. The foramen magnum and occipital condyles do not serve as strong determinants for sexual dimorphism. Nonetheless, this study suggests potential applications in forensic anthropology, paleontology, and medical fields where determining sex from fragmented skeletal remains is essential. © 2024, Indian Academy of Forensic Medicine. All rights reserved.