Patent ID: 8702759

Claim:
A system comprising: a bone anchor assembly comprising: a fixation member configured to secure an inferior or superior facet joints comprising a threaded portion, the threaded portion having a longitudinal axis; a coupling member formed monolithically with the fixation member, the coupling member having a closed loop portion defining a passageway orthogonal to the longitudinal axis of the threaded portion; a compressible member polyaxially adjustably positionable at least partially within the closed loop portion, the compressible member having a compressible bore shaped to receive an elongated member; a locking member configured to be actuated relative to the compressible member to urge compression of the compressible member, wherein the locking member comprises a non-threaded head segment configured to fracture from a threaded segment, wherein the locking member is configured to directly compress an outer surface of the compressible member, and wherein the compression of the compressible member locks the elongated member in a fixed position relative to the assembly, and wherein a threaded aperture is encircled by a ring on a top portion of the coupling member, the exterior of the ring having multiple drive features and a smaller diameter than the closed loop portion of the coupling member, wherein a countersink flares out from a concave wall of the passageway to the outer surface of the coupling member.