The antetorsion angle (beta) of the femoral neck and the "retrotorsion" angle (alpha) of the lesser trochanter were measured in 52 female and 34 male femora taken from 46 human cadavers (age at death 80.3 +/- 8.67 years). In addition, the diameter of the femoral head (d) and the length of the femur (l) were measured. As expected, the antetorsion angle varied over a wide range (beta = 10.5 degrees +/- 9.22 degrees). Measurements on right and left demonstrated an asymmetry: beta right = 8.2 degrees +/- 9.14 degrees; beta left = 12.6 degrees +/- 8.99 degrees. The measurements for retrotorsion of the lesser trochanter also varied in a similar way: alpha total = 31.5 degrees +/- 11.8 degrees; alpha right = 35 degrees +/- 10.7 degrees; alpha left = -28 degrees +/- 11.9 degrees. If alpha and beta are combined to couples, a strong regression is visible (r = 0.7657): beta = 29.5 degrees +/- 0.6 . alpha. Thus, the antetorsion angle depends on the retrotorsion angle or vice versa. The measurements of d and l show marked symmetry: d total = 47.4 +/- 3.6 mm; d right = 47.6 +/- 3.6 mm; d left = 47.2 +/- 3.5 mm; l total = 442.7 +/- 24.6 mm; l right = 441.3 +/- 24.4 mm; l left = 444.0 +/- 24.8 mm. Thus, d and l also vary in dependence on each other (r = 0.578). As the length of the femur is determined by body height, there must be a correlation between the diameter of the femoral head and height; that is to say, a short patient will have a small femoral head.
