Femoral neck anteversion among five canid taxa

Measurements of proximal femoral angles of anteversion and inclination have been part of numerous studies of bone biology in humans and domestic dogs. Among humans, the research stimulus often has been the development of procedures to correct hip (coxofemoral) and knee (stifle in quadrupeds) joint pathology. Among dogs, the frequent goal has involved further understanding of carnivoran bone biology more generally. Based on our previous studies, we hypothesize that considerable variability will be evident within and across selected canid taxa, but statistically different taxon-related measurement outcomes are unlikely. Our subjects include museum specimens from the canid taxa Canis lupus lupus (gray wolf); Canis lupus familiaris (domestic dog); Canis latrans (coyote); Urocyon cinereoargenteus (gray fox); and Vulpes vulpes (red fox). Following surface scans, axes were extracted to represent the femoral neck-shaft and the geometric axis of the distal femoral condyles. Femoral neck anteversion and femoral neck angles were measured, and Kruskal-Wallis tests were done to test for significant differences among the taxa. Spearman rank correlation was used to evaluate relationships of the two proximal femoral angles to femoral length and each other. Data analyses revealed no statistically significant differences among the taxa for femoral neck anteversion or femoral neck angle. The two angles correlated significantly to each other across taxa. There were no significant correlations between femur length and either of the proximal femoral angles. Each taxon revealed variable data for anteversion especially. The data distribution across taxa suggests that the observations most probably represent naturally occurring biological phenomena.