19. A dynamic bone anchor adapted to used in a spinal stabilization system, the dynamic bone anchor comprising: a bone screw having a longitudinal axis, a proximal end and a distal end; the bone screw including a housing at the proximal end thereof, the housing having a bore therethrough aligned with the longitudinal axis; a post received in the bore of the housing such that post extends from the bore at a proximal end of the housing; a joint between the post and a distal end of the housing which pivotally mounts the post to the distal end of the housing such that the post can pivot about a pivot point within the joint; a compliant member positioned between the post and the housing which compliantly aligns the post with the longitudinal axis of the bone screw; and a bone screw thread which extends along said bone screw and a portion of said housing, said bone screw thread extending more proximally than the pivot point at the center of the ball-shaped retainer such that, upon implantation, the bone screw and the portion of the housing are adapted to be implanted in a bone and the pivot point is adapted to be positioned within the bone.
19. A dynamic bone anchor adapted to used in a spinal stabilization system, the dynamic bone anchor comprising: a bone screw having a longitudinal axis, a proximal end and a distal end; the bone screw including a housing at the proximal end thereof, the housing having a bore therethrough aligned with the longitudinal axis; a post received in the bore of the housing such that post extends from the bore at a proximal end of the housing; a joint between the post and a distal end of the housing which pivotally mounts the post to the distal end of the housing such that the post can pivot about a pivot point within the joint; a compliant member positioned between the post and the housing which compliantly aligns the post with the longitudinal axis of the bone screw; and a bone screw thread which extends along said bone screw and a portion of said housing, said bone screw thread extending more proximally than the pivot point at the center of the ball-shaped retainer such that, upon implantation, the bone screw and the portion of the housing are adapted to be implanted in a bone and the pivot point is adapted to be positioned within the bone. 20. The dynamic bone anchor of claim 19 , wherein the compliant member comprises a polymer bushing.