A receiving part for receiving a rod for coupling the rod to a bone anchoring element is provided, the receiving part including a receiving part body (5, 5) with a rod receiving portion (9) with a channel (12) for receiving the rod, and a head receiving portion (16) for accommodating a head (3, 30) of the bone anchoring element, the head receiving portion having an open end (17) and being flexible so as to allow introduction and clamping of the head, the head receiving portion having an exterior surface with a curved portion and a locking ring (8, 8, 8") embracing the head receiving portion (16), and wherein the locking ring has an interior surface with a curved portion (8a), which presses against the curved portion of the exterior surface of the head receiving portion (16) to clamp the head.
