A method of implanting an intervertebral implant or component thereof, in
which each component is selected to have an inner surface and an outer
surface which engages an adjacent vertebra and presents only three
distinct points of contact with a cortical rim of the vertebra. The outer
surface is selected to have a footprint which is sized to be within that
of the cortical rim. In disclosed embodiments, the footprint can be
convexo-concave shaped or kidney shaped. The intervertebral implant can
be provided with upper and lower (or first and second) components which
engage adjacent first and second vertebrae and which move relative to one
another. The implant has both the first and second outer surfaces sized
to present a respective footprint sufficient for two lateral-anterior and
one posterior points of contact with an adjacent cortical rim of the
respective first and second vertebra.