US Patent 7060099 Disk prosthesis for cervical vertebrae with controlled clearance

A disk prosthesis includes first and second plates (2, 3) to be fixed on neighboring cervical vertebrae and an articulation arrangement (7) inserted between the two plates in a superposed position. The articulation arrangement allows for flexion-tension movements in a sagittal plane (S) according to a limited clearance, lateral inflexion movements in a plane perpendicular to the sagittal plane (S) according to limited angular clearance, and relative rotation movements between the first and second plates according to a limited angular clearance. The first and second plates are assembled to form a prosthesis of a single piece.