Patent ID: 7294128

Claim:
A bone fixation apparatus, comprising: a receiver cup comprising at least one receiver engagement portion, said receiver engagement portion comprising a pair of opposed cup flanges, each extending partially around a top outer surface of said receiver, the receiver cup additionally comprising a pair of mating stops, said mating stops comprising recesses in said cup flanges cup; and a cap comprising at least one cap engagement portion that slidably engages the at least one receiver engagement portion when rotated on the receiver cup less than one full rotation, said cap engagement portion comprising a pair of opposed cup flanges, each extending partially around a bottom inner surface of said cap; the cap additionally comprising a pair of mating stops, said mating stops comprising pins extending upward through openings in said cap flanges; wherein a top surface of said cap engagement portion provides a non-threaded engagement with a bottom surface of said receiver engagement portion and additionally comprises a notch on the top surface of the cap aligned with the opposed flanges indicating flange position relative to the receiver cup when in an engaged configuration; and wherein said mating stops on said receiver engagement portion and said mating stops on said cap engagement portion are configured to engage said cap to said receiver cup upon about one quarter turn of said cap on said receiver cup.