The forward projection front abutment surface (50") abuts the front recess abutment surface (74"), and the forward projection back abutment surface (52") abuts the back recess abutment surface (78").

The first member has an associated first bearing surface and the second member has an associated second bearing surface.

The recovery opening (22) is formed outside first land surface (75) and the second land surface (76).

The second land surface (76) is provided at a position further from the surface of the substrate than the position of the first land surface (75).

The second side (15) has an abutment surface (27) for abutting with an abutment surface of a further edge rail adjacent the edge rail.

The first land surface (75) is provided in substantially parallel to the surface of the substrate.

The first land surface (75) can hold the liquid between itself and the surface of the substrate.

The inner wall includes a shoulder (44) and a land (42).

(The normal is a line drawn perpendicular to the surface.)

('Vertical' here means perpendicular to the ground surface.)

Finally, the shape of the supporting surface is crucial.

The annuloplasty ring holder also includes means for attaching an annuloplasty ring to the annuloplasty ring receiving surface.

If the head is thus configured, each spoke will include a portion of the annuloplasty ring receiving surface.

The second land surface (76) is provided so as not to be in contact with a film of the liquid that is present between itself and the surface of the substrate.

An artificial knee joint that includes a femoral component with a specially shaped bearing surface and a tibial component, whose surface interacts with the femoral surfaces.