Patent ID: 8628558

Claim:
A bone fixation subassembly configured to receive a fixation rod and a locking cap, the bone fixation subassembly comprising: an anchor seat including an anchor seat body extending along a central axis and defining an upper end and a lower end, wherein the upper end comprises a pair of opposing fixation rod-receiving gaps therebetween that are spaced along a longitudinal axis, and a bore disposed between the rod-receiving gaps; and a collet including a collet body disposed in the anchor seat, the collet body configured to attach to a bone anchor that extends along an axis of rotation, wherein a bone anchor attached to the collet is permitted to rotate about the axis of rotation relative to the anchor seat, and the bone anchor is further permitted to pivot relative to the anchor seat in a desired plane such that the axis of rotation of the bone anchor can extend on opposed sides of the central axis of the anchor seat within the desired plane and is prevented from pivoting relative to the anchor seat in another plane that includes the central axis and is angularly offset with respect to the desired plane.