The Owl (Apr 2016)
Analysis of Humeral Trochlear Angles as Possible Biological Sex Characteristic
Abstract
Previous research suggests the presence of dramatic variations between the angular traits of female and male humeri. In some populations, this research depicts the difference to be significant enough to accurately determine biological sex. Using the geometric morphometric software TPSDig2 as a new technique, this paper evaluates trochlear angles from photographed dry humeri as a possible determination of biological sex within populations of varying subsistence practices and time periods. The samples include 40 (17 female/23 male) individuals from the archaic population of Windover, Florida and 73 (42 female/31 male) individuals from 6 collections of various subsistence patterns and time periods housed at the University of Tübingen, Germany. The results on the Windover population, a hunter-gatherer group, shows that the left trochlear angles are on average greater than the right trochlear angles by about 6 degrees. In the same population, female left trochlear angles are on average greater than both male right and left angles, but are not statistically significant. When compared to the Tübingen collection, the two hunter-gatherer groups did not display similar trochlear angle distributions. Two of the three medieval groups displayed greater average right angles in both males and females; whereas the remaining medieval group most closely resembled Windover with greater average left angles in males and females. The 7 total collections were compared to each other to test for the accuracy of this method as it might be dependent on factors such as, occupation, time period, robusticity, or handedness. It was ultimately determined that the trochlear angle of the humerus cannot be used as a determinant of biological sex in adults due to exorbitant population variation.
