... inclined to ascribe this to the different anatomical arrangement of the two joints, particularly to the fact that the head of the femur is included in a bony cup, into the hollow of which it is accurately fixed by the resilient cotyloid fibro-cartilage. The latter by its firm grasp of the head allows of little play in the joint; hence vibrations are conveyed directly to the acetabulum in continuous waves, and rocking of the articular surfaces is prevented. Beyond this no doubt the difficulty ... — Surgical Experiences in South Africa, 1899-1900 • George Henry Makins