Locking device for securing a rod-shaped element in a holding element connected to a shank

摘要

A locking device is provided for securing a rod in a receiving part, in particular a polyaxial bone screw. The locking device has a sleeve-type element with a cylindrical outer face and is dimensioned such that the element is displaceable between the legs of the receiving part. The element has an inner thread for receiving an inner screw. An outer nut can be screwed on to an outer thread of the legs to fix the element. The element acts on a pressure element provided in the receiving part to fix the position of the head of the polyaxial bone screw and the inner screw acts on the rod to fix it. The element is preferably provided with slits. During screwing in of the inner screw, the element splays out against the outer nut and thus effectively prevents loosening or detaching.