Patent ID: 7662175

Claim:
A polyaxial bone screw comprising: a) a head having a channel adapted to receive an elongate rod and having a lower bore; b) a shank having a lower portion adapted to be implanted in a bone of a patient and an upper portion; said shank being sized and shaped to be uploaded into said head through said bore; c) a retainer ring separate from said shank and received in said head; said retainer ring mating with and secured to said shank upper portion so as to polyaxially rotate with the shank relative to the head and so as to form a combined shank and retainer ring prior to locking of the position of the shank relative to the head, the combined shank and retainer ring presenting a head engaging surface larger than said head bore so as to hold said shank in said head while allowing polyaxial movement of said shank and retaining ring relative to said head during positioning; and d) said shank upper portion being sized and shaped so as to extend into said channel after said shank is received in said head and engage a rod under pressure after the rod is received in the head channel.