Abstract: The invention relates to a screw (1), preferably a bone screw, comprising a shaft (2) with a tip (3), a head (4) and a thread (5). The shaft further comprises a longitudinal axis (A). An array of radial cross-sectional surfaces (Q) of the head (4) extend through the longitudinal axis (A) of the screw (1), the location of each radial cross-sectional surface (Q) being defined by an azimuth angle (6) in a plane (E) perpendicular to the longitudinal axis (A). Each radial cross-sectional area (Q) has an area defined by the longitudinal axis (A) and the outer surface of the screw (8). The thread (5) extends into the head (4) in such a way that the surface areas of the radial cross-sectional surfaces (Q?) in a first azimuth angle range (9) are constant and the surface areas of the radial cross-sectional surfaces (Q?) in a second azimuth angle range (10), which is different from the first, have a different, preferably smaller, value than the surface areas in the first azimuth angle range (9).