15. A spinal rod comprising; a rod having a longitudinal axis; a rod-end comprising an aperture adapted to be secured to a bone anchor; and a set screw; wherein the rod-end is connected to the rod by a joint which permits the rod-end to, at least one of, slide along the longitudinal axis of the rod, and rotate around the longitudinal axis of the rod; and wherein the set screw is configured to apply a force to the rod to lock the rod relative to the rod-end.
15. A spinal rod comprising; a rod having a longitudinal axis; a rod-end comprising an aperture adapted to be secured to a bone anchor; and a set screw; wherein the rod-end is connected to the rod by a joint which permits the rod-end to, at least one of, slide along the longitudinal axis of the rod, and rotate around the longitudinal axis of the rod; and wherein the set screw is configured to apply a force to the rod to lock the rod relative to the rod-end. 17. The spinal rod of claim 15 , wherein the rod-end comprises a substantially cylindrical bore in which a first end of the rod is received.