[A morphological and functional analysis of the extent of cartilage coverage in the human hip joint]

The extension and the shape of the cartilage surface of 30 human femora and acetabula were measured. The results were considered and discussed as the response of the articular cartilage to the specific stress on this joint. 3 kinds of cartilage distribution were found on the femoral head; these shapes were understood as the consequence of the position and the dwelling time of the actual cartilage stimulating area. The largest extention of the cartilage was found in the ventrolateral direction and the smallest in medial direction. The cartilage margin of the "A" type was regulary curved. The "B" type has an inlet towards the fovea capitis. This inlet reaches in the "C" type to the fovea as an area free of cartilage. The acetabula could not be divided into types with different cartilage distribution because of the great similarity in shape. Therefore we computed an average acetabulum. The largest extension of the facies lunata was found 15 degrees in front of the roof of the acetabulas as seen in x-ray pictures. The cornu anterius is always narrower than the cornu posterius. The outer margin of the osseous acetabulum does not reach the equator, it lies on a latitude of 11.5 degrees. The incisura acetabuli is inclined against the vertical line with 18.3 degrees. The width of the facies lunata can be considered as a result of mechanical stress. The different extensions of the cartilage of both joint components in ventro-lateral direction seems to be the consequence of different extensions of movement. The area of movement of the caput femoris is larger than the area of the acetabulum.