A polyaxial bone fixation system has a bone screw with a head having an outer thread and a shaft. A bone plate has an upper face and a lower face and a through-bore for receiving the bone screw. The bone screw is introduced into the through-bore at a selectable angle and can be fixed in the through-bore at the selected angle. Material openings extend around the through-bore such that between the through-bore and each material recess opening, a bridge is formed which runs continuously from the upper face to the lower face. The bridge forms a protuberance which protrudes into the through-bore and runs in the longitudinal direction of the through-bore. The radius of the through-bore is reduced in the region of the protuberance. The bridge can plastically deform when the bone screw is screwed into the through-bore.
