A screw and rod fixation assembly includes a body member including a screw seat for seating a screw head therein and a rod seat for seating a rod therein. An adjustable locking ring applies a locking force against the screw head seated in the screw seat and a locking cap adjustably applies a locking force against a rod seated in the rod seat. The adjustable screw locking ring and locking cap function independent of each other. A method of fixing the rod to the screw includes the steps of inserting a screw head into a screw seat in one end of a body member and inserting a rod into a rod seat in a second end of a body member and selectively and independently adjusting a locking force on both the screw head and the rod within the screw seat and rod seat, respectively.
