Double-expansion hollow forcing screw

The utility model relates to a screw used for fixing odontoid fractures. The screw consists of a hollow external screw and an inner screw bolt, wherein two ends of the hollow external screw are provided with screw threads, the hollow external screw has expansibility, and the inner screw bolt is used for inserting the external screw so that the two ends of the external screw expand. The utility model provides a double-expansion hollow forcing screw, which has the advantages that the screw is used in an anterior odontoid fracture screw internal fixation operation, on the basis of not increasing the number of screws, the bicortial fixation is reached through external screw threads arranged at the head end and the tail end, meanwhile, through the double-expansion design at the head end and the tail end, the fixation intensity and the anti-rotation capability of the single screw can be effectively improved, and the firm fixation of the fracture broken end is more favorably realized, so the fracture healing rate is