A spinal fixation system is provided that includes a coupling member and a locking device that is operable to fix an elongate member relative to the coupling member. In one form, locking device includes opposing lock arms operable to retain the locking device relative to the coupling member in an initial position prior to the locking device fixing the elongate member relative to the coupling member. In another form, the coupling member and locking device include cooperating structure therebetween in the form of a protrusion and a guide track, the cooperating structure arranged and configured to retain the locking device within an internal space of the coupling member. There is also provided a retainer operable to minimize pivoting of the coupling member relative to an anchor member and to substantially retain an anchor member depressed within an internal space of the coupling member to minimize play therebetween.