Sex determination by discriminant function analysis using the human tibia in a Central Indian population

Abstract

In human beings, sexual dimorphism can be well distinguished in almost every bone of the skeleton. Establishing a reliable biological profile is the foremost step in identifying human skeletal remains. Sex determination along with the estimation of age, stature and ancestry comprise the important parameters in establishing a biological profile. The pelvis and skull are considered the most reliable bones in sexing human remains. In the absence of the pelvis and skull, forensic scientists must rely upon other parts of the skeleton for sex assessment. Determination of sex from long bones based on morphological traits can be a challenging task, as there are a few morphological differences between the sexes for long bones. However, metric variations can prove to be helpful, as they are reproducible and more reliable. Metric analysis also has the added benefit of being less biased than nonmetric analysis. This study aimed to establish sex determination standards from tibiae using discriminant function analysis. A total of 17 measurements were taken on 162 dry tibiae (116 males and 46 females) of known sex and in the age range 20–60 years. Discriminant function analysis was performed to derive models for sexing of the tibiae. The breadth of the medial articular surface was observed to be the best parameter for sex prediction from metric measurements of the tibia. In stepwise analysis, only seven parameters – namely, the breadth of the medial articular surface, the condylo-malleolar length, the circumference at the nutrient foramen, the breadth of the lateral articular surface, the maximum length, the transverse diameter in the middle of the bone and the transverse diameter at the level of the nutrient foramen – were entered into the discriminant functions. Overall, the accuracy of sexing was observed to be 93.8% and 95% with the direct method and the stepwise method, respectively. This study provides a database and standards for sex estimation from tibiae based on discriminant function models. This investigation further concludes that tibiae can be used for sex determination in forensic examinations.