Artificial joint as an endoprosthesis for the human shoulder joint

Abstract

The invention at hand concerns an artificial joint, in particular an endoprosthesis for a human shoulder joint, consisting of two parts, a joint head (3) and a joint pan (2) with spherical joint surfaces moving relative to one another. The bending conditions of the functional surfaces (5,7) are convex-concave in the frontal plane as well as in the perpendicular transverse plane. The joint geometry of the functional surfaces towards each other in both planes is determined through a dimeric joint chain which runs through the rotation centers of the functional surfaces of each of the intersection contours. The joint head (3) and the joint pan (2) are arranged in relation to their functional surfaces such that in their position corresponding to the rest position of the arm in a dangling state the functional surfaces (5,7) have the same radius of curvature in the contact area (8) on both sides in the frontal plane with a linear contact of the functional surfaces (5,7), and such that a roll-off area (9) adjoins, in which the radii R.sub.P1, R.sub.K1 of both functional surfaces (5,7) are selected such that a circumferentially widening gap section covers the area between both joint parts (2,3).