A device for securing a spinal rod (212) to the spine comprises a head portion (222), a locking cap (220) and a fastener portion (224). The fastener portion (224) depends from the head portion (222) for engaging the spine. The head portion (222) has a channel (228) extending therethrough for receiving the spinal rod (212), the channel (228) being bounded by opposed side walls (230, 232) each having a slot formed therein. The locking cap (220) has a first portion (220a) having opposed flanges (284, 286) receivable in the slots (294, 296) of the head portion (222) and a second portion (220b) having an underside (299) engageable with the exterior surface of the spinal rod (212). Said first and second portions of the locking cap (220) are mechanically joined for rotation relative to one another.
