Sex determination based on sacral and coccygeal measurements using multidetector computed tomography in a contemporary Japanese population

- We assessed sex-discrimination potential of the sacrum and coccyx.
- CT images of the sacrum and coccyx were used in this study.
- All measured lengths except one showed significant sexual dimorphism.
- We developed discriminant function equations for predicting sex.
- Metric analysis of the sacrum and coccyx may be useful in some cases.

Sex determination is an integral and foremost step in determining the identity of an unknown individual. The present study aimed to examine skeletal sexual dimorphism of the sacrum and coccyx using computed tomography (CT) images in a contemporary Japanese population and to derive discriminant function formulae for sex determination. Data were collected from 230 cadavers (115 male and 115 female subjects) subjected to postmortem CT scanning and subsequent forensic autopsy. Seven measurements of the sacrum and coccyx were obtained from CT images of each subject. The measurements were analyzed using descriptive statistics and discriminant function analyses. All except one measurement exhibited statistically significant sexual dimorphism, and the maximum sex determination rate was 83.5% according to discriminant function analyses. The results of this study suggest that discriminant analysis of sacral and coccygeal traits may be useful for the sex determination of skeletal remains in the Japanese population when applied with additional methods, such as morphological trait evaluation of other available bones.

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