1. A specially designed loading apparatus and dyeing technique have been used to demonstrate the weight-bearing areas in fifty-one normal adult hip joints.

2. Under loads and positions typical of the stance phase of walking the entire articular surface of the acetabulum is involved in weight-bearing. This contact area is reproduced on the femoral head, and its position determined by the attitude of the femur to the acetabulum.

3. With loads typical of the swing phase, the dome of the acetabulum and corresponding areas on the femoral head are not involved in weight-bearing.

4. The results are compared with the conclusions of previous investigators and their possible significance with regard to joint degeneration is discussed.

1. The routes by which adult human articular cartilage can receive its nutrition is still a subject of controversy.

2. Microscopic examination of normal adult human femoral heads has revealed vascular channels which penetrate the subchondral plate and calcified cartilage. These channels bring the medullary soft tissue into contact with the articular cartilage.

3. A fluorescent dye migration technique was used to show that the observed vascular channels are pathways for dye from the medullary cavity to the articular cartilage. It is suggested that these pathways could also be routes by which articular cartilage receives part of its nutrition.

4. The nutritional mechanism in the mature rabbit and adult human femoral heads cannot be compared because histological studies revealed differences in their subchondral structures.