Abstract: Presented herein is a bone screw system that comprises a fixation element, a receiving element, coupling element, and a compression element. The fixation element can be a screw. The receiving element defines an internal bore sized to receive the shank portion of the fixation element and a seat adapted to support the head portion of the fixation element. The seat of the receiving element is shaped to substantially conform to an exterior portion of the head portion of the fixation element. A breakaway groove is positioned externally on each leg or leg extension. The breakaway groove extends inwardly at least partially through the wall of each leg or leg extension. This creates an aperture or slit in the wall leaving the wall with at least on, preferably a pair of leg attachments on each leg or leg extension adjacent the aperture.