FIXATION DEVICE FOR BONES

摘要

A bone fixing device is provided to prevent a bone screw from breaking away from a cage or a plate even in case the bone screw becomes loosened in vertebral bodies. A bone fixing device comprises a member and a bone screw(30'). The member is fixed to one or more bones(40,42). The member has one or more bores(2'). The bore contains the bone screw. The bore comprises a first female thread part(22). The bone screw is inserted through the bore within the bone. The bone screw comprises a first shaft part, a head part(36) and a second shaft part. The first shaft part comprises a first male thread part(32). The first shaft part is combined with the first female thread part of the bore. The diameter of the head area is larger than the diameter of the shaft part. The head part provides a catch(35). The catch is combined with a stopper(50) formed in bore. The second shaft part comprises a clearance groove(34a). The clearance groove is extended between the catch of the head part and a male thread of the first shaft part.