Sex Estimation from the Fibula and Tibia: A Study in Three Portuguese Reference Collections

Background/Objectives: Sex estimation constitutes an important tool in the process of identifying an anonymous individual in forensic contexts. The bones commonly used in sex estimation are those that exhibit greater sexual dimorphism, such as the pelvis or the femur. However, these bones are not always available, which means that it is necessary to find alternative bones for analysis. The main purposes of this study include the assessment of fibular and tibial sexual dimorphism in samples from three Portuguese reference skeletal collections, and the development of metric models for the estimation of biological sex. Methods: A sample of 290 individuals (160 females; 130 males), belonging to the Coimbra Identified Skeletal Collection (training sample), the Lisbon Identified Skeletal Collection (test sample), and 21st the Century Identified Skeletal Collection (training sample), was employed to develop models for sex prediction through logistic regression. Results: From the identification of the most dimorphic bone dimensions, 13 models were created with an accuracy ranging between 80.1% and 89.7% in the training sample (under cross-validation), and between 82.5% and 91.7% in the test sample Conclusions: The results of this work show that predictive models based on the fibula and tibia can be accurate and unbiased.