Abstract: The present invention relates to a spinal implant having a plate with a raised platform which rests in a channel in a vertebrae to prevent sideways movement of the plate. A rib extends into a groove formed in the base of the channel to help prevent relative forwards and backwards movement of the plate through the channel. Another plate is similarly secured to the facing surface of an adjacent vertebrae. A spacer is inserted between the plates, such spacer including a downwardly facing convex surface and a flat upwardly facing surface. The convex surface slides in a concave recess provided on top of the plate and the flat surface slides against a downwardly facing flat surface of the upper plate.