US Patent 7318825 Dynamic cervical plates and cervical plate constructs

N-level internally dynamizing cervical plates and cervical plate constructs in accordance with the present principles, provide unconstrained sliding interconnection between the various plate components after installation on a cervical spine. A tongue-and-groove configuration between the various plate segments provides a constant thickness over the dynamizing portions. Detents provided relative the tongue-and-groove portions allows the various plate components to be permanently joined, but movable relative to one another. Various bone screw anti-backing, anti-rotation or locking devices for cervical bone plates are also provided that allow releasable locking of bone screws relative to the cervical plate.