Articulating spinal disc prosthetic

A spinal disc prosthetic for replacement of cervical and/or lumber discs, that in each case allows a limited degree of rotational articulation, as well as durability and resistance to fatigue. The prosthetic is formed with three primary layers, including a superior (upper) plate, inferior (lower) plate, and intermediate layer, in a sandwich. The superior plate member is adapted to be secured on one side to an upper vertebra in a spinal column, and has a formed concave side exposed downwardly. The inferior plate member is adapted to be secured on one side to a lower vertebra in the spinal column, and has a substantially flat side exposed upwardly. The intermediate member is sandwiched between the superior and inferior plate members with conforming sides, and includes a short cylindrical post protruding downward into a circular recess in the inferior plate member to center it and to maintain a predetermined spacing there between. Two lateral pins on the intermediate member fit into two corresponding slots on the inferior member as guides and allow a degree of rotational freedom, and the post includes snap-in spring fingers that lock into the recess of the inferior member to prevent withdrawal.