Bone anchoring device

A method of attaching a bone anchoring device to a bone or vertebrae, the bone anchoring device comprising a bone anchoring element having a shaft for anchoring to a bone and a head, a receiving part for coupling a rod to the hone anchoring element, wherein the receiving part comprises a first portion comprising two legs each having a free end and defining a U-shaped recess for receiving the rod and a second portion defining an accommodation space for accommodating the head, the second portion having a free end and being flexible so as to allow introduction of the head into the accommodation space and clamping of the head when the head is in the accommodation space, and a locking ring configured to be mounted to the receiving part from the free end of the second portion and to be positioned around the second portion, the method comprising:

• attaching the bone anchoring element to a bone or vertebrae;
• inserting the head of the bone anchoring element into the second portion of the receiving part, wherein when the head is in the accommodation space and the locking ring is at a resting position relative to the receiving part, the second portion of the receiving part compresses the head of the bone anchoring element with a first force to temporarily hold the bone anchoring element at an adjustable angular position relative to the receiving part by friction;
• inserting a rod in the U-shaped recess;
• and
• exerting pressure on the locking ring by the rod to cause the locking ring to move from the resting position to a locking position, where the receiving part compresses the head with a second force greater than the first force to lock the angular position between the bone anchoring element and the receiving part.