Bone Plate With Retainer and Stop for Screw Lock

Abstract

A bone plate, having a bone screw and a rotatable lock for retaining the bone screw in place, includes a retainer element and/or a stop element. The retainer element inhibits the lock from being pushed off of the bone plate, while the stop element limits the rotational range of motion of the lock.

We claim: 
     
         1 . A bone plate comprising:
 a plate formed of a biocompatible material and having an upper surface;   at least one screw hole formed in the plate; and   a stop element positioned on the plate upper surface;   wherein, when a rotatable screw lock is rotatably mounted to the upper surface of the plate, at a position relative to the at least one screw hole so that, in a first unlocked position the screw lock does not impede passage of a bone screw through the at least one screw hole, and in a second locked position the screw lock does impede passage of a bone screw through the at least one screw hole, the stop element prevents the screw lock from complete rotation.   
     
     
         2 . A bone plate according to  claim 1 , further comprising:
 a rotatable screw lock mounted to the plate upper surface, the screw lock including a central portion and a laterally extending flange, the screw lock rotatable from said first unlocked position to said second locked position.   
     
     
         3 . A bone plate according to  claim 2 , further comprising:
 a retainer element positioned adjacent to the screw hole and forming a gap between the retainer and the plate upper surface;   wherein, when the rotatable screw lock is in the first unlocked position, the screw lock does not impede passage of a bone screw through the at least one screw hole, and, when the rotatable screw lock is in the second locked position, the screw lock does impede passage of a bone screw through the at least one screw hole, a portion of the screw lock positioned in the gap when in the second position.   
     
     
         4 . A bone plate according to  claim 1 , further comprising:
 a retainer element positioned adjacent to the screw hole and forming a gap between the retainer and the plate upper surface;   wherein, when the rotatable screw lock is in the first unlocked position, the screw lock does not impede passage of a bone screw through the at least one screw hole, and, when the rotatable screw lock is in the second locked position, the screw lock does impede passage of a bone screw through the at least one screw hole, a portion of the screw lock positioned in the gap when in the second position.   
     
     
         5 . A bone plate according to  claim 4 , wherein the stop is positioned immediately adjacent to the retainer. 
     
     
         6 . A bone plate according to  claim 4 , wherein the retainer includes a laterally extending portion having a bottom surface, the bottom surface spaced from the top surface of the plate, the gap located between the laterally extending portion bottom surface and the plate upper surface. 
     
     
         7 . A bone plate according to  claim 1 , wherein the stop element includes a vertically extending wall. 
     
     
         8 . A bone plate according to  claim 1 , wherein the stop is positioned remotely from the at least one screw hole. 
     
     
         9 . A bone plate comprising:
 a plate formed of a biocompatible material and having an upper surface;   at least one screw hole formed in the plate; and   a retainer element positioned adjacent to the screw hole and forming a gap between the retainer and the plate upper surface; and   wherein, when a rotatable screw lock is rotatably mounted to the upper surface of the plate, at a position relative to the at least one screw hole so that, in a first unlocked position the screw lock does not impede passage of a bone screw through the at least one screw hole, and in a second locked position the screw lock does impede passage of a bone screw through the at least one screw hole, the screw lock passes under the retainer element when moving between the first and second positions.   
     
     
         10 . A bone plate according to  claim 9 , further comprising:
 a rotatable screw lock mounted to the plate upper surface, the screw lock including a central portion and a laterally extending flange, the screw lock rotatable from said first unlocked position to said second locked position.   
     
     
         11 . A bone plate according to  claim 9 , wherein the retainer includes a laterally extending portion having a bottom surface, the bottom surface spaced from the top surface of the plate, the gap located between the laterally extending portion bottom surface and the plate upper surface.