Abstract: A a spinal fixation system comprises an elongated fixation plate having a bottom side for facing the vertebrae, an opposite top side extending generally parallel to the bottom side, and an elongated slot defined therethrough which extends substantially along the length of the plate. The slot has a lower edge at the intersection of the slot and the bottom surface and an upper edge at the intersection of the slot and the top surface with a number of concave depressions formed at each edge. In one embodiment, the concave depressions at the lower and upper edges of the slot form comparable scalloped surfaces. In another embodiment, the lower edge of the slot forms a single concave surface extending around the entire perimeter of the lower edge of the slot. The system further includes a pedicle screw and a nut for load transmission between the vertebrae and the fixation plate. The pedicle screw includes a threaded nut engaging portion, a threaded bone engaging portion and an intermediate portion therebetween.