Patent ID: 7306606

Claim:
A bone screw assembly comprising: a coupling member comprising a lower surface and a channel opposite the lower surface, the channel being formed by two arms extending from a base portion; a hole extending through the coupling member from the base portion of the channel to the lower surface of the coupling member; a spacer within the hole of the coupling member, the spacer having a top surface adjacent to the base portion of the channel and a bottom surface generally opposite the top surface; a hollow retaining ring within the hole of the coupling member, the retaining ring comprising an inner surface, an outer surface, a top surface spaced from the bottom surface of the spacer, and a slot extending from the inner surface of the ring to the outer surface of the ring; and a bone screw comprising: a head portion having a top surface, an outer surface adjacent to the inner surface of the retaining ring, and a recessed channel extending around the periphery of the head portion and spaced from the top surface of the head portion; and a threaded portion extending from the head portion; wherein the top surface of the retaining ring at least partially extends into the recessed channel of the bone screw head portion.