KUMJ | VOL. 23 | NO. 5 | ISSUE 93 | DECEMBER, 2026

Study of Sexual Dimorphism from Sternal End of Ribs
Shrestha A, Timilsina S, Shrestha S, Sharma B

Abstract:
Background Sex estimation is a fundamental component of the biological profile in forensic anthropology. The sternal ends of ribs exhibit significant sexual dimorphism. Objective This study evaluates sexual dimorphism of the sternal ends of ribs in a Nepalese population using discriminant function analysis. Method A cross-sectional analysis was performed on 90 autopsied individuals aged between 15 and 74 years. Sternal end measurements supero-inferior height and anteroposterior breadth from the 2nd to 7th ribs were taken with Vernier calipers. Data were analyzed using SPSS-26 with descriptive statistics, independent t-test and discriminant function analysis. Result The sample of 50 males and 40 females showed statistically significant sexual dimorphism in all rib measurements (p < 0.05). The supero-inferior height of the right fourth rib demonstrated the strongest discriminating power, evidenced by the highest canonical correlation (0.526), highest eigenvalue (0.382) and lowest Wilks’ Lambda (0.723). Its classification accuracy was 96.9% for original cases and 71.9% after cross-validation, with consistent high accuracy of 96.9% in younger age groups (15-32 years) and 94.8% in older age groups (33-74 years). The antero-posterior breadth of the right second rib was the second most predictive variable. Conclusion Rib morphometry, specifically of the right fourth and second ribs, provides a reliable method for sex estimation in the Nepali population. The discriminant functions developed in this study offer valuable forensic applicability, especially in cases involving incomplete or fragmented remains where more sexually dimorphic bones are unavailable.
Keyword : Anthropometry, Rib morphometry, Sex estimation, Sexual dimorphism, Nepal