Patent ID: 8425576

Claim:
A bone fixation apparatus in which a threaded fastener passes through a hole in a plate and into a bone to affix the bone to the plate during use, the bone fixation apparatus comprising: a plate having a hole extending through the plate, the plate having top and bottom surfaces on opposing sides of the plate with the hole having a circular opening on both surfaces and with the bottom surface being adjacent to the bone during use, the openings having a longitudinal axis through the center of the openings, the hole having a portion of at least a first spherical cavity therein centered on the longitudinal axis, a plurality of resilient spring members integrally formed as an inseparable part with the plate and encircling the opening on the top surface, an annular groove in the plate centered on the longitudinal axis and extending a distance into the plate to define a length of the spring members and an outer surface of the spring members facing away from the longitudinal axis, a plurality of slots in the plate extending into the plate about the length of the spring members to define sides of the spring members, an inner side of the spring members facing the longitudinal axis having a curved surface defining a portion of the first cavity, the spring members configured to move resiliently outwards away from the longitudinal axis to allow a portion of the fastener to be positioned in the opening, and configured to move resiliently inwards after insertion of a portion of the fastener to resist removal of the fastener from the plate until the resistance of spring members is overcome.