Sexual Dimorphism in Mandibular Ramus Morphometry: A Population-Specific Analysis Using Orthopantomograms in the Lucknow Region

Abstract

Introduction Identification is a fundamental aspect of forensic anthropology, which is crucial for legal investigations, archaeological research, and disaster victim identification. The skull and pelvis exhibit significant sexual dimorphism to aid sex determination. In cases where the intact skull is unavailable, the mandible, particularly the ramus, serves as a vital bone for sex determination due to its distinct morphological characteristics. Aim To determine sex from the mandibular ramus using orthopantomograms (OPGs) and to develop a population-specific discriminant function for sex determination in the Lucknow region. Materials and methods This cross-sectional study was conducted from October 2024 to November 2024 and involved OPGs of 100 adults (55 males and 45 females) aged 20-50 years, selected randomly from patients referred to the Department of Dental Sciences at Era's Medical College and Hospital, Lucknow. Measurements were done for the bigonial distance, projective ramus height, maximum ramus height, maximum anteroposterior diameter, and minimum anteroposterior diameter. Statistical analysis of data was done using IBM SPSS Statistics version 26.0 (IBM Corp., Armonk, NY), employing descriptive statistics, independent t-tests, and discriminant functions to evaluate the significance and accuracy of the measurements in sex determination. Results Significant sexual dimorphism was observed in various mandibular measurements, particularly bigonial distance, projective heights of the right and left ramus, and maximum heights of the right and left ramus (p < 0.001). The discriminant function achieved an overall accuracy of 96% in sex determination, with an accuracy of 94.5% in males and 97.8% in females. Conclusion The mandibular ramus is an effective tool for sex determination, exhibiting significant sexual dimorphism. Discriminant function has been developed to provide a reliable method of sex determination with high accuracy. Bigonial distance and projective ramus height were identified as the most significant parameters for sex determination. These findings contribute to forensic anthropology by offering a population-specific method for sex determination using mandibular ramus measurements and further support forensic investigations.

Keywords: anthropology; forensics; morphometry; radiography; skull; tomography.

Figure 1. Orthopantomogram of the mandible showing labeled measurements (in cm), including bigonial distance, projective ramus height, maximum ramus height, and maximum and minimum anteroposterior (AP) diameter of the ramus.