Patent ID: 7604664

Claim:
An artificial intervertebral disc, comprising: a first member having a first exterior vertebral body contact surface, a first inner surface angled with respect to the first exterior vertebral body contact surface, and a first side surface formed between the first exterior vertebral body contact surface and the first inner surface; a second member having a second exterior vertebral body contact surface, a second inner surface angled with respect to the second exterior vertebral body contact surface, and a second side surface formed between the second exterior vertebral body contact surface and the second inner surface, the first and second members being disposed such that the vertebral body contact surfaces face away from one another; and a coupling by which the first and second members are coupled to one another such that the first and second vertebral body contact surfaces are angulatable relative to one another about a centroid of motion centrally located between the first and second vertebral body contact surfaces, the coupling including a protrusion having a semi-spherical surface with at least one slot therein and a restoring force providing element seated in a circular recess formed in one of the inner surfaces of the first and second members, the restoring force providing element having a curvate socket wherein the semi-spherical surface of the protrusion only fits through and becomes seated in the curvate socket when radially compressed such that the at least one slot narrows; and a shield coupled to the second plate and overlying the circular recess such that the restoring force providing element is captured within the circular recess, wherein no structure contacts the side surfaces of the first and second members during angulation of the first and second members relative to one another.