A spinal plate system and method for fixation of the human spine is provided. In an embodiment, the spinal fixation system includes a plate, a coupling member and a locking system for substantially locking the coupling member in a desired position. The plate preferably has a borehole that allows the coupling member to couple the plate with a bone. Preferably, at least a portion of the coupling member may swivel in the hole so that a bottom end of the member extends at a plurality of angles substantially oblique to the plate. The locking system preferably locks the coupling member in desired positions relative to the plate. An assembly tool is preferably used to inhibit rotation of the coupling member during the installation of the spinal fixation system.