[The coxal end of the femur. An architecture following strict rules].

In order to combine the dynamic hip screw with a plate that anchors the greater trochanter, detailed measurements of the greater trochanter are necessary and its relation to the femoral head and neck must be studied. The hips in 200 X-ray films in the AP view were measured. The radiographs were obtained from 46 males and 87 females (69.2 +/- 16.9 years old) without hip disease. Concerning the neck shaft angle, no selection was done. The axis of the femoral head and neck was drawn; a second horizontal line passed through the apex of the lesser trochanter. Both lines intersected the lateral cortex of the femur. The distance between those two intersections was measured: d = 0.41 +/- 0.28 cm. In the next step, 74 human femora were obtained from 21 females and 17 males (79.9 +/- 9.0 years old). A special gauge was fixed at the lateral site of the femur. Using this gauge, the size and shape of the greater trochanter were measured: (1) the apex of the greater trochanter lay exactly on the line, which was determined by the lateral cortex of the femoral shaft (+/- 0.4 cm); (2) the maximum lateral extension of the greater trochanter was measured half-way from the lesser trochanter niveau to the apex of the greater trochanter (minor-major distance: 6.09 +/- 0.82 cm; minor-lateral maximum distance: 3.03 +/- 0.59 cm); (3) the maximum lateral extension of the greater trochanter measured 11.4 +/- 3 mm.