Patent ID: 8663291

Claim:
An assembly for a polyaxial screw consisting essentially of: a bone anchor having a spherical connector and a shank with at least one thread formed along a length of said shank, a connector assembly having a first side wall and a second side wall each having a U-shaped opening, said connector assembly including an internal passageway having a wall that extends from a first end to a second end, a diameter of the internal passageway being greater than the diameter of the spherical connector at said first end and the diameter of the internal passageway at said second end being smaller than the diameter of the spherical connector, said internal passageway further including a groove formed in said wall of the internal passageway, and a retaining ring positioned within said groove, said groove includes an upper end wall, a lower end wall and a sidewall therebetween, said sidewall of said groove is angularly positioned wherein a junction of the upper end wall and said sidewall of said groove forms a first annulus having a first diameter and a junction of the lower end wall and said sidewall of said groove forms a second annulus having a second diameter, said second annulus diameter is greater than said first annulus diameter; wherein as the shank is inserted into the first end of said internal passageway and out of the second end of the internal passageway the spherical connector is moved past the retaining ring which is initially expanded to allow the spherical connector to pass and once past the retaining ring will return to its unexpanded state and prohibit the removal of the spherical connector from the connector assembly.