A bone fixation apparatus having an elongated plate member with at least two pairs of circular openings and a series of openings positioned along the longitudinal plane of the plate member with the circular openings and the series of openings each having a central vertical axis. The circular openings and series of openings each form a cavity with walls extending between the upper and lower plate member surfaces with at least a plurality of the cavities having smaller diameter portions at the plate member upper and lower surfaces and a larger diameter portion therebetween. The cavities are configured in the shape of two inverted cones with matching base circles for allowing transverse and longitudinal angulation of an implanted bone screw. A plurality of bone screws each have a threaded first end portion adapted for implantation into a patient's bone mass and a generally ellipsoid shaped enlarged second end portion. A locking member connects to the second end portion of each bone screw for expanding the second end portion so as to grip the cavity wall of the plate member and for locking each bone screw into a selected position within the circular openings and series of openings of the plate member.