An implantable orthopedic assembly comprises an occipital plate and one or more repositionable clamping assemblies for securing a stabilizing rod to the plate. When unlocked, the clamping assembly may be laterally and rotationally repositioned along a supporting rail. Locking occurs when a stabilizing rod is secured in the clamping assembly. The rod exerts a force upon a locking component, causing the locking component to exert a force upon the supporting rail. This force pulls a surface of the clamping assembly base into contact with the rail, effectively locking the clamping assembly base at a fixed position. The clamping assembly may further comprise a loading component to exert a stabilizing force on the locking component, keeping the clamping assembly positionally stable while adjustments are made prior to locking.
