BONE SCREW WITH AXIALLY TWO-PART SCREW HEAD

摘要

The invention relates to a bone screw (14; 28) that is provided with a screw shaft (1) that is to be anchored in the bone in a direction coaxial with respect to the longitudinal axis (3) of the screw and with a screw head (2). Said bone screw (14; 28) is configured as an axially composite element. At least the screw head (2) is axially two-part and comprises a screw shaft low er part (4) and a terminal upper part (5) that is linked with the lower part (4 ) and/or the screw head (1). The invention also relates to a device for the osteosynthetic bone fixation with at least one such bone screw (14; 28). Sai d device comprises A) at least one plate-shaped, prismatic or cylindrical fixation element (41) that is provided with at least one bore (37) with a center axis (30) for receiving the bone screw (14; 28) and a screw shaft low er part (36) and a screw head upper part (33). The invention is also characterized in that B) the bore (37) comprises a concave section (39) that tapers in the direction of the lower part (36); and C) the diameter of the lower part (4) is chosen such that the lower part (4) can be accommodated in the concave section (39) of the bore (37) at different angles between the longitudinal axis (3) of the screw and the center axis (30) and is placed on the wall (40) of the bore (37).