Determination of sex in South Indians and immigrant Tibetans from cephalometric analysis and discriminant functions

Skeletal components play significant role in sex determination in forensic and anthropological fields. Skull is considered second best, after pelvis, in determination of sex. Methods based on morphological characteristics and morphometry are already in use with reasonable accuracy. Standardized radiographic techniques like cephalometry have advantages of being more precise and objective when compared to morphologic methods. The present study aimed at obtaining and comparing the reliability of cranio-mandibular parameters in South Indian and Indian immigrant of Tibetan populations using lateral and postero-anterior (PA) cephalograms. A total of 11 cephalometric parameters were traced on lateral and PA cephalograms manually. Functions to aid in the sex determination were developed by subjecting the cephalometric parameters to discriminant analysis. Among the chosen parameters bizygomatic width, ramus height, depth of face contributed most for sexual dimorphism in both the populations. Upper facial height was the additional parameter for sexual dimorphism in immigrant Tibetan population. The discrimination accuracy in South Indian population was 81.5% while that of immigrant Tibetan population was 88.2%. With the current study it can be concluded that cephalometric cranio-mandibular parameters can be used to discriminate the sex using discriminant function analysis and similar cranio-mandibular parameters contribute to sex prediction across populations.