Estimation of sex from measurements of foramen magnum region in a contemporary Jordanian population: A computed tomographic study.

Several studies have shown variability in basicranial measurements between populations. Therefore, each population should have specific standards to optimize the accuracy of identification. The aim of this study was to evaluate the sexual dimorphism in foramen magnum and occipital condyles measurements using 3D multidetector computed tomography (MDCT), and to assess their utility and reliability for sex estimation in a Jordanian population by means of discriminant function analyses. A total of 500 MDCT scans (288 males and 212 females) were used and a total of 8 basicranial measurements were studied (3 measurements were derived from foramen magnum, and 5 measurements were derived from occipital condyles). Significant sexual dimorphism was found in all basicranial measurements. The most dimorphic variables were length of occipital condyle and maximum bicondylar distance. Including all variables, multivariate and stepwise functions gave an overall accuracy of 77.8% and 78.6%, respectively. However, the multivariate analyses conducted separately for measurements derived from foramen magnum and occipital condyles gave lower overall accuracy of 68.6% and 70.0%, respectively. Basicranial measurements derived from foramen magnum alone predicted males with relatively higher accuracy but were poor at predicting females in the sample (82.6% were males, 49.5% were females, sex bias 33.1%). Adding occipital condyles measurements to the multivariate analysis increased the percentage of correct sexing in females and reduced considerably the sex bias (78.8% male, 76.4% female, sex bias 1.4%). Discriminant function analysis using basicranial measurements derived from both foramen magnum and occipital condyles measurements can be utilized to estimate sex in our population.