Sex estimation using direct gonial angle measurement in 16-24 years old Indonesian population

Introduction: Sex determination an important role in post-mortem (PM) profile reconstruction, which enables to reduce the possibility of identification. Gonial angle (GA) of mandible is a reliable sex parameter through skeletal examination. However, given frequent limited resources in forensic setting, direct GA measurement approach on deceased’s body is more practicable. Objectives: This study aims to evaluate GA discriminative ability in sex estimation by using direct measurement method in 16-24 years old Indonesian population. Material and methods: One hundred individuals (M = 43, F = 57) between 16-24 years old from Jepara District, Central Java, Indonesia, were selected for the measurement of both left (LGA) and right (RGA) gonial angle using a goniometer. Inter-and intra-observer reliability were 0.906 and 0.936, respectively, after one month using intra-class correlation coefficients (ICC). Measured LGA and RGA from males and females were compared using Mann-Whitney U -test, and Pearson’s correlation between LGA and RGA were calculated. Binary logistic regression and ROC curve models were applied to analyze GA capability in sex discrimination. Results: There was no significant difference between LGA and RGA measurements, and a high correlation was detected ( r = 0.73). Both LGA and RGA had significant value to predict sex. AUC value of LGA was 0.615 ( p = 0.048; 95% CI: 0.51-0.73) and RGA was 0.637 ( p = 0.015; 95% CI: 0.53-0.74). Conclusions: The proposed direct examination method of GA to predict sex shows a low discriminating performance on both LGA and RGA variables.