Femoral asymmetry in healthy adults: elliptic Fourier analysis using computerized tomographic scout views.

Morphology (both size and shape) of paired structures differ in the left and right sides of body. Size and shape characteristics should be analyzed separately to supply information about the normal variations of human organs. In the present study, the within-subject size and shape asymmetries of normal human femur were analyzed from a mathematical standpoint. On the standardized frontal computerized tomographic scout views of both thighs of 14 healthy adults (7 women and 7 men aged 22-26 years), the outline of the femur was identified, and its size and shape were separately quantified. The left and right femur of each subject were compared, and size and shape asymmetry separately quantified on an intra-subject basis. Subjects were also grouped for sex, and mean values computed. Within-subject symmetry in femoral size and shape was high, with coefficients of superimposition ranging between 91% and 96.5%. In women, a slightly higher symmetry (up to 99.9%) was observed when the femoral outlines were standardize for size. Moreover, in the same group the asymmetry in the form of femoral outline seemed to be partly related to the asymmetry in femoral length. Conversely, no similar relations were found in men.