37. The bone anchor assembly of claim 30 , wherein the closure has a corresponding continuous helically wound structure engageable with the receiver discontinuous guide and advancement structure.
37. The bone anchor assembly of claim 30 , wherein the closure has a corresponding continuous helically wound structure engageable with the receiver discontinuous guide and advancement structure. 38. The bone anchor assembly of claim 37 , wherein the closure is configured to abut the elongate rod received in the receiver first channel.