Osteometric analysis of intercostal variation and sexual dimorphism in the sternal end of the rib of modern American blacks

Research on the human rib has shown that the sternal end of this bone manifests differences in age, sex and race. It was also found that intercostal variation may affect the expression of these traits. The purpose of this study is to osteometrically analyze intercostal variation and sexual dimorphism in ribs 1-7 from a known sample of American black males (N = 110) and females (N = 52) collected from recent forensic autopsy cases. Results indicate that although intercostal variation is significant, there is too much overlap to metrically determine rib position. Sexual dimorphism is sufficient to develop discriminant function formulae that separate males and females with a minimum accuracy of 75% (rib 1) and a maximum of 83% (rib 4). However, these functions are population and rib specific. This research confirms earlier findings on ribs 3-5, and expands the potential to determine sex from ribs 1-7.