The morphology of the knee joint in Homo sapiens : a morphometric study of form variation in the distal femur and proximal tibia
This thesis explores form variation in the knee joint of thirteen geographically and economically distinct populations of modern Homo Sapiens from different ancestral backgrounds. Shape differences are interpreted within the context of the size of the knee joint and against size differences in the femur and tibia. Three dimensional coordinate data are taken from the distal femur and proximal tibia and statistical shape analysis is conducted using geometric morphometric techniques. Results from initial intra-population analyses using a restricted number of samples determine the data that are submitted for inter-population analyses using the full dataset. Three series of intra-population analyses test for asymmetry, sexual dimorphism and age. Significant shape asymmetry exists in all samples examined. Results therefore preclude the use of both right- and left- sided specimens within any single sample in subsequent analyses. Results indicate the existence of a significant degree of sexual dimorphism in all samples, but that the nature and degree of variation is population specific. For both sexual dimorphism and shape variation with ageing, differences are of lesser significance relative to inter-population variation. Using the full dataset, results indicate the existence of size and (particularly) shape differences between samples at a high level of statistical significance. Morphological variation between populations arises from a number of influential factors, including climate and more specifically, cold temperature. The powerful influence of additional factors, including working practices, disease and nutrition is examined in greater depth in relation to the Spitalfields sample from London, which shows a distinctive pattern of form variation relative to the other population samples.