Sex estimation from the femur using discriminant function analysis in a Central Indian population

Sexual dimorphism is one of the major factors responsible for apparent variations in human skeletal anatomy. Establishing the biological profile of the deceased is essential for personal identification in forensic and archaeological casework. To develop a reliable biological profile, sex allocation is an integral step required to determine age, race/ancestry and stature, given observable differences in aging and growth patterns and variations in morphological traits relating to ancestry. Sex estimation from long bones by visual examination is very difficult. However, metric observations are more objective and effective. This osteometric analysis focused on sex estimation from the femur using discriminant function analysis. Fourteen measurements were taken directly on 175 dry femora (117 males and 58 females), aged 20–60 years, from the Chhattisgarh region of Central India. Student’s t-test was applied to assess significant sex and size differences. Direct and stepwise discriminant function analyses were applied to derive discriminant function models for sex estimation. The three parameters that were selected for the discriminant function analysis included: transverse head diameter, bi-trochanteric distance and maximum shaft diameter. Males were more accurately classified than females. An overall accuracy of 80.6% was reported with direct discriminant function analysis and 76% with stepwise discriminant function analysis upon cross-validation. The transverse head diameter emerged to be the best predictor of sex. This study provides a database and standards for sex estimation from skeletal remains of an unknown nature based on discriminant function equations. This is one of the few studies conducted in India on dry bones, and we anticipate that it will guide forensic specialists in the identification of unknown skeletons from this region.