Patent ID: 11925391
Assignee: BIEDERMANN TECHNOLOGIES GMBH & CO. KG
Field: Medical technology (Instruments)
Classification: CPC A | IPC A

Claim 18:
19. A bone anchoring device for coupling a rod to a bone, the bone anchoring device comprising:
a bone anchoring element comprising a shank for anchoring to the bone and a head;
a receiving part having a first end, a second end below the first end, a central axis extending through the first end and the second end, a recess for receiving the rod, and an accommodation space for accommodating the head of the bone anchoring element;
a retainer element positionable at least partially in the accommodation space, wherein the retainer element is expandable to facilitate insertion of the head into the accommodation space and comprises an upwardly facing surface configured to contact and to exert an upwardly directed pressure on the head;
a pressure element positionable at least partially in the accommodation space and separable from the retainer element, wherein the pressure element comprises a downwardly facing surface configured to contact and to exert a downwardly directed pressure on the head for locking the head in the receiving part; and
a third element separable from the receiving part, the retainer element, and the pressure element, wherein when the retainer element, the pressure element, and the third element are assembled to the receiving part and the head is in the accommodation space, an upper end of the third element is positioned axially above a lower end of the pressure element while a lower end of the third element is positioned axially below the lower end of the pressure element, and the third element is configured to restrict expansion of the retainer element to hold the head in the receiving part.