The invention relates to an osteosynthesis device.The osteosynthesis device comprises a cervico-cephalic screw (1) provided with a distal thread able to be screwed into the bone, a support (3) formed by a plate with a shape suitable for fixing same to the bone or by an intramedullay nail able to be inserted into the medullary cavity, and a blocking means (6) blocking the screw in the support and movable in the support along the axis of the screw, and the final positioning of the screw is variable.The device is intended for holding in place and compressing fragments of a fractured bone.
