The present application relates to a facet joint prosthesis comprising a first component having a first disc with a first outer face for engagement of a first bone. The first outer face has an opposed first inner face, which includes a first post connecting said first disc to a tongue. The facet joint prosthesis further comprises a second component having a second disc with a second outer surface for engagement with a second bone. The second outer surface has an opposed second inner face, which comprises a bridge located near the periphery of said second disc. Said bridge connects the second disc with a third disc. The third disc comprises a pocket. Insertion of said tongue into said pocket and rotation of said tongue relative to said pocket results in a locking of said tongue between said second disc and said third disc.
