A motion restoring intervertebral device includes first and second
articulating components positioned between adjacent vertebrae with the
articulating surface of the first component being formed by a circular
domed convex projection having a first radius. The articulating surface
of the second component is formed by a generally concave recess having
the first radius in the medial-lateral direction and a second larger
sweeping radius in the interior-posterior direction so that the
components are capable of rotating against each other in all directions
and translate against each other in the anterior-posterior direction,
whereby translation away from the center of the first radius will produce
device and joint distraction to limit excessive translation.