21. A dynamic bone anchor adapted for use in a spinal stabilization system for a spine, the dynamic bone anchor comprising: a bone screw having a longitudinal axis, the bone screw having a housing at a proximal end, the housing having a bore therethrough aligned with the longitudinal axis of the bone screw, the bore having a distal end and a proximal opening; the housing having an external surface with a plurality of surface features adapted to engage a device mounted on the external surface to prevent rotation of the device relative to the dynamic bone anchor; a post received in the bore of the housing, the post having a longitudinal post axis; a ball-joint connecting the post and a distal end of the bore, whereby the ball-joint pivotally mounts the post to the distal end of the bore; the post having at a second end a mount which extends from the proximal opening of the bore; and a compliant member positioned between the post and the housing which compliantly aligns the longitudinal post axis of the post with the longitudinal axis of the bone screw, said compliant member is adapted to align the longitudinal post axis of the post with the longitudinal axis of the bone screw as the spine applies a load on the dynamic bone anchor for spinal stabilization.
21. A dynamic bone anchor adapted for use in a spinal stabilization system for a spine, the dynamic bone anchor comprising: a bone screw having a longitudinal axis, the bone screw having a housing at a proximal end, the housing having a bore therethrough aligned with the longitudinal axis of the bone screw, the bore having a distal end and a proximal opening; the housing having an external surface with a plurality of surface features adapted to engage a device mounted on the external surface to prevent rotation of the device relative to the dynamic bone anchor; a post received in the bore of the housing, the post having a longitudinal post axis; a ball-joint connecting the post and a distal end of the bore, whereby the ball-joint pivotally mounts the post to the distal end of the bore; the post having at a second end a mount which extends from the proximal opening of the bore; and a compliant member positioned between the post and the housing which compliantly aligns the longitudinal post axis of the post with the longitudinal axis of the bone screw, said compliant member is adapted to align the longitudinal post axis of the post with the longitudinal axis of the bone screw as the spine applies a load on the dynamic bone anchor for spinal stabilization. 24. The spinal implant of claim 21 , wherein the plurality of surface features comprise a plurality of splines.