Patent ID: 9603630
Date: 2017-03-28
CPC Classifications: A61B,Y10T

Claim:
1. A multi axial screw assembly, comprising: a) a bone anchoring member extending between a head and a shaft; b) a receiver member having a channel configured to receive a rod and an aperture extending along a central axis of the receiver member, the aperture being generally cylindrical and having a diameter, the receiver member further having an internal groove with a top and bottom surface; c) a base member received within the aperture of the receiver member, the base member extending along an axis between a deflectable ring and a second end surface, the deflectable ring being configured to mate with the top and bottom surfaces of the internal groove of the receiver member and a slot within the deflectable ring configured to allow the deflectable ring to compress to a diameter less than the diameter of the aperture such that the base member may be compressed and axially received within the receiver member and then released to engage the groove of the receiver member thereby axially restraining the base member relative to the receiver member while allowing for relative rotation between the base member and the receiver member, the slot extending through the deflectable ring without extending through the second end surface, the base member including a cutout extending through the second end surface without extending through the deflectable ring, the base member including a sidewall extending between the deflectable ring and the second end surface and having a uniform outer diameter therebetween; and d) a crown configured to be received within the receiver member along the central axis of the receiver member, the crown having an outer surface that is received within the base member to maintain the diameter of the deflectable ring greater than the diameter of the aperture, wherein the bone anchoring member is movable between a first position in which the shaft extends parallel to the axis and a second position in which the shaft extends through the cutout at an angle that is transverse to the axis.