[Investigations concerning the extension of the cartilage surface of the femoral head (author's transl)].

The extension of the cartilage surface of 30 human femoral heads was measured from the center of the fovea capitis. In ventrolateral direction of the fovea the largest extension of cartilage was observed, in the medical direction the lowest extension. The different arrangement of the cartilage distribution pattern on the medial head area resulted in three types: whereas type A had a continuous cartilage margin, type B showed an inlet in the direction of the fovea capitis, which, in type C, extended right up to the fovea as an area free of cartilage. The findings are considered under functional aspects and are related to the stress of the hip joint. A calculation of the cartilage area proved that the morphological geometric conditions for an enarthrosis are not fulfilled in all cases. These calculations were performed assuming both a spherical and a small ellipsoidal curvature of the head surface.