Fig. 2

Three-dimensional bone model showing the relationship between osseous landmarks and the footprints of the capsular ligaments. a Anteroposterior view of the femur. Line A indicates the length of the intertrochanteric line. Line B indicates the length of the distal footprint of the medial arm. F/I ratio = B/A × 100 (%). The circle shows the footprint of the distal medial arm. b Superior view of the femoral neck. Line C indicates the anteroposterior length of the femoral neck at the junction of the greater trochanter and femoral neck. Line D indicates the length of the distal footprint of the ischiofemoral ligament. F/FN ratio = D/C × 100 (%). The circle shows the footprint of the distal ischiofemoral ligament. The dotted line shows the femoral neck axis