Patent ID: 8603169

Claim:
An artificial disc for spinal implantation comprising: a first upper joint member having a first side defining an attachment surface attachable to a vertebra and having a second side having a first articulation surface; and a second lower joint member having a first side defining an attachment surface attachable to a vertebra and having a second side having a second articulation surface; wherein the first articulation surface engages the second articulation surface in sliding engagement to allow for movement of the artificial disc; and wherein the artificial disk experiences constrained coupling of movement such that lateral bending of the upper joint member relative to the lower joint member causes lateral translation of the upper joint member relative to the lower joint member in the same direction as the lateral bending; and wherein said lateral bending also causes axial rotation of the upper joint member relative to the lower joint member whereby a point on the anterior edge of the upper joint member moves due to said rotation in the same direction as the lateral bending movement.