Patent ID: 7674279

Claim:
A bone plate comprising: a plate having a top surface and a bottom surface; at least two screw holes extending through the plate, the at least two screw holes having centers positioned apart at a distance A; a hole extending through the plate, the hole positioned generally between the at least two screw holes at a distance X from a line connecting the centers of the at least two screw holes; a rotatable locking device positioned in the hole, the rotatable locking device including first portions which extend above the plate top surface, second portions extending through the hole toward the bottom surface, and a center of rotation coincident with the center of said hole; wherein the first portions define a longest portion of length L, extending laterally from one side of said center of rotation to another side of said center of rotation, a curved top surface having a radius of curvature R 1 , a thickness T at said center of rotation, a widest portion of width W 1 at an end of the longest portion, and a narrowest portion of width W 2 , adjacent said center of rotation; and wherein L= 1·(sqrt( R 1 2 −( R 1 −T ) 2 )), with 1.5≦1≦2.5, W 1 =R 1 /w 1 , with 2.0 ≦w 1 ≦2.7, and W 2 =R 1 /w 2 , with 3.0 ≦w 2 ≦3.7.