Use of Foramen Obturatum and Subpubic Angle in Sex Determination: Diagnostic Accuracy of Anthropometric Measurement on MDCT Images

  Sex determination from skeletal bones is very important, especially for forensic science and anthropology. Radiological techniques are commonly used for this purpose. This study aimed to evaluate the accuracy rate of the subpubic angle and width-length ratio of foramen obturatum (FO) in sex determination and determine the cut-off values for differentiation between genders.
Patients and Three-dimensional (3D) volume-rendered images were obtained from the pelvic CT scans of 100 patients (50 female, 50 male). The subpubic angle was automatically measured on these images using image analysis software. The maximum width and height of FO were recorded and their ratio were calculated. The subpubic angle was between 75.9 and 101.2 in females (mean: 82.92 ± 15.06) and, 47.4 and 91.5 in males (mean: 67.91 ± 9.15). The accuracy rate of the subpubic angle in determining sex was 96%. For the best cut-off value of 79.45 on the subpubic angle, the parameters for sex determination were as follows: sensitivity 84%, specificity 74%, positive predictive value (PPV) 76%, and negative predictive value (NPV) 82%. The aspect ratio of FO was 0.48 - 0.74 (mean: 0.60 ± 0.039) for the right side and 0.48 - 0.72 (mean: 0.60 ± 0.054) for the left side in females, and 0.45 - 0.68 (mean: 0.55 ± 0.058) for the right side and 0.45 - 0.69 (mean: 0.54 ± 0.052) for the left side in males. For the best cut-off value of 0.615 on the right side, the parameters for sex determination were as follows: sensitivity 84%, specificity 74%, PPV 76%, and NPV 82%. The accuracy rate of the right-side FO in sex determination was 79%. For the best cut-off value of 0.635 on the left side, the parameters for sex determination were as follows: sensitivity 98%, specificity 32%, PPV 59%, and NPV 94%. The accuracy rate of the left-side FO in sex determination was 65%. The subpubic angle and aspect ratio of foramen obturatum parameters have high accuracy in determining sex.