Patent attributes
A spinal fixation system includes a rod, an anchor, and a clamp assembly. The anchor is adapted to engage a bone. The clamp assembly secures the anchor to the rod. The clamp assembly includes a first portion with first and second flanges for receiving the anchor. A compressible ball is carried by the second portion of the clamp assembly. The ball has a through hole receiving the rod. The through hole is defined by a generally cylindrical inner surface having at least one relieved channel. The first and second flanges include first and second opposing surfaces, respectively. The first and second opposing surfaces are normally angled relative to one another. A nut which threadably engages an upper shaft of the fastener is tightened to draw together the first and second flanges to a position in which they are generally parallel to one another. At least a portion of the through hole tapers from one of the first and second ends towards a center of the ball.