Patent ID: 7699880

Claim:
A bone fixation system, comprising: a) a bone plate including a dynamic compression bone screw hole; b) a bone screw having a non-threaded head portion having a upper surface, a lower surface, a peripheral surface extending therebetween, and a circumferential groove extending about the peripheral surface, and a shaft portion provided with bone-engaging threads extending from said head portion; and c) a split ring discrete from said bone screw, said ring substantially completely recessed in said groove and rotationally fixed relative to said bone screw, said ring having first and second ends, said ring recessed such that only said first end extends out of said groove so as to contact said bone plate surrounding said bone screw hole and provide rotational resistance when said bone screw is rotated in a direction of disengagement from bone, wherein said bone screw hole includes at least one access opening extending from an upper portion of said plate to a lower portion of said head portion of said screw when said head portion of said screw is seated in said bone screw hole.