Bone screw

摘要

A bone screw comprises a receiver member (5) and a screw member (1) having a threaded portion (2) and a head (3) having a spherical segment-shaped portion. The receiver member (5) comprises an internal thread (10) for allowing a relative adjustment of receiver member and screw member and the connection of the receiver member with a round rod. A pressure means (12) acts onto the head (3) and the rod (16) is placed on top of the pressure means. The arrangement is locked by means of a rod locking nut (13) and a lock nut (14) is screwed onto an external thread (11).