Patent ID: 7033396

Claim:
A shoulder or hip prosthesis comprising a humeral or femoral component having a concave articulation surface (S 1 ) and an intermediate component having first and second convex articulation surfaces (S′ 1 ) (S′ 2 ), intended to cooperatively slide when the prosthesis is in use, respectively, against said concave articulation surface of said humeral or femoral component and against a concave glenoid or cotyloid articulation surface (S 2 ), natural or belonging to a glenoid or cotyloid component, wherein a locus of instantaneous centers of rotation (C 1 ) of said first convex articulation surface (S′ 1 ) with respect to the concave humeral or femoral articulation surface (S 1 ) and a locus of instantaneous centers of rotation (C 2 ) of said second convex articulation surface (S′ 2 ) with respect to said glenoid or cotyloid articulation surface (S 2 ), are located on opposite sides of said first convex articulation surface (S′ 1 ) thereby facilitating movement of abduction of the prosthesis.