The present invention provides for a screw and rod fixation assembly for fixing a screw and, optionally, a rod. The screw and rod fixation assembly includes a screw, fixing mechanism, a substantially annular ring, rod seating mechanism, and locking mechanism. The present invention also provides for a fixing mechanism for fixing a screw, wherein the fixing mechanism further includes an inner surface wall having a gripping portion and a non-gripping portion. Further, the present invention provides for a substantially annular ring for guiding and providing mechanical and frictional force to a screw head. Additionally, the present invention provides for a rod seating mechanism operatively engaged to the screw head and including at least one flexible portion capable of being compressed against a portion of a rod therein. Finally, the present invention provides for a locking mechanism for engaging the rod and the rod seating mechanism. The locking mechanism includes a deflecting mechanism for deflecting the at least one flexible portion of the rod seating mechanism against and around the rod as the locking mechanism further engages the at least one flexible portion of the rod seating mechanism. <；IMAGE>；The present invention provides for a screw and rod fixation assembly for fixing a screw and, optionally, a rod. The screw and rod fixation assembly includes a screw, fixing mechanism, a substantially annular ring, rod seating mechanism, and locking mechanism. The present invention also provides for a fixing mechanism for fixing a screw, wherein the fixing mechanism further includes an inner surface wall having a gripping portion and a non-gripping portion. Further, the present invention provides for a substantially annular ring for guiding and providing mechanical and frictional force to a screw head. Additionally, the present invention provides for a rod seating mechanism operatively engaged to the screw head and including at least one flexible portion capable of bein
