Polyaxial bone anchoring device and system including an instrument and a polyaxial bone anchoring device

A bone anchoring device comprising:

• a receiving part for coupling a rod to a bone anchoring element, the receiving part comprising a first end, a second end below the first end, a central axis extending between the first end and the second end, a recess at the first end for receiving the rod, and a head receiving portion at the second end for pivotably holding a head of the bone anchoring element, the head receiving portion being at least partially flexible;
• a pressure member positionable in the receiving part and configured to exert pressure on the head when the head is held in the head receiving portion of the receiving part;
• and
• a clamping ring positionable around the head receiving portion, wherein when the clamping ring is around the head receiving portion, the clamping ring is movable from a first position wherein an inserted head is pivotable relative to the receiving part, to a second position wherein the clamping ring exerts a radial force onto the head receiving portion to lock the inserted head relative to the receiving part;
• wherein when the clamping ring is at the first position, a portion of the clamping ring abuts a portion of the receiving part to restrict movement of the clamping ring towards the first end of the receiving part, while a surface of the clamping ring that faces upwards towards the first end of the receiving part is exposed to an outside of the bone anchoring device for engaging an instrument to move the clamping ring to the second position.