A pedicle screw (100, 200) comprising a tulip head (8, 208), a rod seat (10, 210), a screw shank, a locking ring (6, 206), and a retainer collar (4, 204), in said pedicle screw: the tulip head (8, 208) having an upper opening (81, 281) disposed in a top end (83, 283) of the tulip head (8, 208) and a lower opening (82, 282) disposed in a bottom end (84, 284) of the tulip head (8, 208) opposite the upper opening (81, 281), wherein: the upper and lower openings (81, 82; 281, 282) form a single cavity extending through the tulip head (8, 208) from the top end (83, 283) to the bottom end (84, 284), and the cavity has an interior wall, a retention groove (86, 286) disposed within the interior wall, internal threads (94, 294) disposed within the interior wall and adjacent to the upper opening (81, 281), and a stop disposed between the retention groove (86, 286) and the upper opening (81, 281), wherein the locking ring (6, 206) is disposed within the retention groove (86, 286); the rod seat (10, 210) disposed within the cavity and having a stop engageable with the stop of the cavity of the tulip head (8, 208), the rod seat (10, 210) having a rod mating face (12, 212), a shank mating face (14, 214) opposite the rod mating face (12, 212), and a hole (18, 218) disposed through the rod mating face (12, 212) and shank mating face (14, 214); the screw shank having a thread disposed along a length of the screw shank and a connector positioned at an upper end of the screw shank; and the retainer collar (4, 204) having a collar body (41, 241), a pass through aperture (48, 248) disposed through the collar body (41, 241), a locking ring groove (34, 234) disposed within an outer surface of the collar body, and a collar expansion split disposed within the collar body, wherein the retainer collar (4, 204) is disposed about the connector of the screw shank, and the locking ring (6, 206) is disposed within the locking ring groove (34, 234), wherein the stop of the cavity of the tulip head (8, 208) extends inwardly from the interior wall of the cavity to engage the stop of the rod seat (10, 210) to thereby prevent the rod seat from moving into the upper opening (81, 281) of the cavity, and wherein the stop of the rod seat (10, 210) includes a pair of retention ledges (16, 216), the tulip head (8, 208) includes a pair of arms (91, 291) defining a U-shaped channel (92, 292) transverse to the cavity, the arms defining the stop of the cavity of the tulip head, wherein the retention ledges are engageable with the arms (91, 291) to thereby prevent rotation of the rod seat relative to the tulip head. the tulip head (8, 208) having an upper opening (81, 281) disposed in a top end (83, 283) of the tulip head (8, 208) and a lower opening (82, 282) disposed in a bottom end (84, 284) of the tulip head (8, 208) opposite the upper opening (81, 281), wherein: the upper and lower openings (81, 82; 281, 282) form a single cavity extending through the tulip head (8, 208) from the top end (83, 283) to the bottom end (84, 284), and the cavity has an interior wall, a retention groove (86, 286) disposed within the interior wall, internal threads (94, 294) disposed within the interior wall and adjacent to the upper opening (81, 281), and a stop disposed between the retention groove (86, 286) and the upper opening (81, 281), wherein the locking ring (6, 206) is disposed within the retention groove (86, 286); the upper and lower openings (81, 82; 281, 282) form a single cavity extending through the tulip head (8, 208) from the top end (83, 283) to the bottom end (84, 284), and the cavity has an interior wall, a retention groove (86, 286) disposed within the interior wall, internal threads (94, 294) disposed within the interior wall and adjacent to the upper opening (81, 281), and a stop disposed between the retention groove (86, 286) and the upper opening (81, 281), wherein the locking ring (6, 206) is disposed within the retention groove (86, 286); the rod seat (10, 210) disposed within the cavity and having a stop engageable with the stop of the cavity of the tulip head (8, 208), the rod seat (10, 210) having a rod mating face (12, 212), a shank mating face (14, 214) opposite the rod mating face (12, 212), and a hole (18, 218) disposed through the rod mating face (12, 212) and shank mating face (14, 214); the screw shank having a thread disposed along a length of the screw shank and a connector positioned at an upper end of the screw shank; and the retainer collar (4, 204) having a collar body (41, 241), a pass through aperture (48, 248) disposed through the collar body (41, 241), a locking ring groove (34, 234) disposed within an outer surface of the collar body, and a collar expansion split disposed within the collar body, wherein the retainer collar (4, 204) is disposed about the connector of the screw shank, and the locking ring (6, 206) is disposed within the locking ring groove (34, 234), wherein the stop of the cavity of the tulip head (8, 208) extends inwardly from the interior wall of the cavity to engage the stop of the rod seat (10, 210) to thereby prevent the rod seat from moving into the upper opening (81, 281) of the cavity, and wherein the stop of the rod seat (10, 210) includes a pair of retention ledges (16, 216), the tulip head (8, 208) includes a pair of arms (91, 291) defining a U-shaped channel (92, 292) transverse to the cavity, the arms defining the stop of the cavity of the tulip head, wherein the retention ledges are engageable with the arms (91, 291) to thereby prevent rotation of the rod seat relative to the tulip head.