This joint (Articulatio coxæ) is an enarthrosis formed by the proximal
end of the femur and the acetabulum.
=Articular Surfaces.=—The head of the femur presents an almost
hemispherical articular surface, which is continued a short distance on
the upper surface of the neck. It is more extensive than the socket
which receives it. Internally it is cut into by a deep notch for the
attachment of the round and pubo-femoral ligaments. The acetabulum is a
typical cotyloid cavity. Its articular surface is somewhat crescentic,
being deeply cut into internally by the acetabular notch and fossa. It
is increased and deepened by a ring of fibro-cartilage, the =cotyloid
ligament= (Labrum glenoidale), which is attached to the bony margin;
that part of the ligament which crosses the notch is called the
=transverse ligament= (Fig. 456).
[Illustration: