There are significant correlations between the surface of the acetabular roof sclerosis (supercilium acetabuli) in the hip joint on a normal a.p. radiograph and the corresponding surface of cartilage. This correlation can be defined through mathematical formulas and scaled afterwards. These scales are determined on the basis of our clinical experience with the new supercilium acetabuli score. The score is related to the biomechanical situation of the hip joint and describes 3 classes: Class I = optimum, class II = balance, class III = imbalanced correlation between the supercilium acetabuli and the corresponding part of the joint space. For simple measurement of both surfaces, we developed a measuring instrument, the superciliometer, with which it is possible to obtain standardized conclusions describing the functional morphology of the cartilage in the pressure distribution zone of the hip joint, irrespective of whether there are already any visible radiological signs of coxarthrosis or not.