Determining sex with the clavicle in a contemporary Spanish reference collection: A study on 3D images

Abstract

Sexual dimorphism of the clavicle based on metric studies has been determined among different populations from different eras. Due to the need to know about sexual dimorphism in the Spanish population in order to apply the results to the field of Forensic Anthropology, a study has been carried out on a sample in the contemporary Spanish population, made up of the right and left clavicles of 50 males and 50 females. A metric, volumetric and curvature study was performed. To do so, 3D scanning was completed on the entire sample using the Picza 3D Laser Scanner, and the study was performed using reproductions. There were taken 6 metric measurements and 4 volumetric measurements using the Geomagic software, and for the study of curves, an index was calculated which related the direct length of the clavicle and its length as cast onto a surface. The data are presented for all of the variables, distinguishing between the right and left side, and there were processed using the statistical program PASW Statistics 18. The results show that the classification functions which best categorize the sample with an unique variable are volumetric, which classify the sample correctly in 94% of cases based on diaphysis volume, followed by total volume, which provides an accurate classification in 92% of all cases. The sagittal diameter at midshaft provides an accurate classification in 90% of cases and the maximum length in 88% of cases. The curvature index shows that there are no statistically significant differences by side and the only curvature index that shows significant differences by sex is the total anterior curve of the left clavicle being the males curve more pronounced. The validation study performed on a sample of 20 individuals confirms the high discriminatory power of the volume obtaining an accurate classification rate of 85-100% depending on the variable studied.

Keywords: 3D scanning; Clavicle; Forensic anthropology population data; Sexual dimorphism; Spanish population; Volume.