A bone screw is provided including a tubular body (1) having a first end (2) and a second end (3), wherein the tubular body has a tubular wall defining a cavity and wherein a plurality of openings are provided extending through the tubular wall into the cavity； an exterior bone thread on an exterior tubular surface of the tubular wall； a head (8) configured to engage with a driver to advance the bone screw in the bone by rotating the driver in a first direction, the head being also configured to connect to the tubular body at the first end (2)； wherein the head is connectable to the tubular body in such a way that it is locked against disconnection from the tubular body when the driver is rotated in a second direction opposite to the first direction.
