Patent ID: 7753956

Claim:
A prosthetic disc for insertion between adjacent vertebrae, the prosthetic disc comprising: a mobile core having upper and lower curved surfaces; upper and lower plates, each plate having an outer surface which engages a vertebra and an inner curved surface which slides and translates over the curved surface of the mobile core when the prosthetic disc is implanted, wherein the upper and lower curved surfaces of the core comprise two oppositely facing convex low-friction surfaces which slidably engage the inner curved surfaces of the upper and lower plates; and a peripheral restraining structure on at least one of the upper plate, the lower plate and the core, the peripheral restraining structure configured to hold the mobile core against a curved surface of at least one of the plates during sliding movement of the plates over the core, wherein the peripheral restraining structure is located on at least one of the plates and contacts the other plate to limit relative inclination of the plates during sliding movement of the plates over the core, wherein the other plate comprises a formation that contacts the peripheral restraining structure to limit relative inclination of the plates during sliding movement of the plates over the core.