Acetabular cup for hip proshesis

The cotyloid cup (1) has a hemispherical outer surface (2) with its centre located on its axis of revolution outside the plane defined by the open end of the cup. Both inner (3) and outer (2) surfaces of the cup are hemispherical in shape, the outer surface having a radius greater than that of the inner surface, while the centre of the latter is located at the centre of the cup's open end. The outer wall of the cup has a series of anti-rotation elements, especially in the form of peripheral fins, and it also has a number of circular and longitudinal grooves, the latter extending from the pole of the cup to its open end. The inner periphery of the cup, close to its open end, has a toothed crown (8) and, where appropriate, annular grooves (9) to retain a liner of plastic, e.g. a low-friction polyolefin, or ceramic material.