Abstract: A prosthesis for replacing a surface in an area of a ball of a ball-and-socket joint includes a spherical shell section having an outer surface that is configured to lie in an articular fossa and is for attachment to a surface. The shell section having a cavity for receiving a bone end. The prosthesis also includes a crown that partitions the cavity of the shell section into a first cavity and a second cavity wherein a shape of the shell section is at least a section of a hemisphere and a free edge of the crown lies in the same plane as a free edge of the shell section.

Abstract: An implantable prosthesis having at least two portions which are displaceable relative to each other, in particular a prosthesis for the upper end of a human upper arm comprising a shaft which can be inserted into a bone passage and a dome-shaped joint head which is to be associated with the adjacent joint head and which can be connected to an end face of the shaft in an eccentric position or a neutral position relative to the center axis thereof by means of an intermediate disk which has a circular periphery and which comprises both in relation to the joint head and in relation to the shaft a respective insert pin or the like peg-shaped portion formed thereon which can be inserted into a bore, wherein the mutually displaceable portions of the prosthesis are arranged steplessly displaceably relative to each other at at least one displacement plane which is determined by the surface of a portion about axes which are determined by the insert pins of the intermediate disk.