A bone plate assembly for stabilizing adjacent bones, the bone plate assembly having screw bores therein. The screws are dimensioned to sit within the screw bore and a resilient “S” shaped arm is engaged to the plate and partially covers the screw bore until contacted by the head of the screw. Contact with the head of the screw while the screw is being advanced into the bone pushes the resilient arm away from the head and, when the screw is seated in the screw bore, the resilient arm springs back to at least partially block the top of the screw head. In this manner, the screw is prevented form backing out of the plate.
