and saddle 40 subassembly 10 can be positioned in such a way that they fit onto a bone screw 2 which has been driven into the bone by the use of a driver tool inserted into the tool drive opening 5 that can already be pre positioned in a pedicle or other bone structure of a patient in this fashion the tulip 20 and saddle 40 combined assembly 10 are configured to be moved over and above the bone screw 2 already positioned in the bone fit onto the head 4 of the bone screw 2 adjusted for angularity due to the fact that the saddle 40 is not tightened and therefore the tulip 20 and saddle 40 subassembly 10 are free to move in any axial direction about the hemispherical or partial hemispherical portion of the head 4 of the bone screw 2 the advantage of the present invention is that the angularity and fixing assembly 10 on the bone screw 2 to the head 4 is all accomplished at one element the saddle 40 as the rod 60 and set screw 80 are assembled and tightened the movement of the saddle 40 having a plurality of flexible compressible and deflectable fingers 42 having an inner surface 41 complimentary to the head 4 of the screw 2 but past the maximum diameter dmax ensures that upon compression the entire assembly 10 is fixed so that the tulip 20 cannot be pulled or slipped off the bone screw 2 once affixed this creates a tremendous advantage over prior art devices requiring additional components the present invention achieves this locking of the tulip assembly 10.