Receiving part for receiving a rod for coupling the rod to a bone anchoring element

1 . A bone anchoring device comprising:

a bone anchoring element comprising a shaft and a head;

a receiving part for receiving a rod for coupling the rod to the bone anchoring element, the receiving part comprising:

a receiving part body having a first end, a second end, a channel at the first end for receiving the rod, an engagement surface for engagement with a separate closure element for locking the rod in the channel, an accommodation space for accommodating the head of the bone anchoring element, and an opening at the second end sized for inserting the head therethrough into the accommodation space; and

a seat insertable through the opening of the receiving part body and positionable at least partially in the accommodation space to engage and hold the head in the accommodation space;

wherein when the seat is in the receiving part body at an insertion position, the head of the bone anchoring element is insertable through the opening of the receiving part body into the accommodation space;

wherein the seat is adjustable from the insertion position to a pre-locking position to restrict the head from being removed from the receiving part body through the opening, where the seat is pivotable together with the receiving part body relative to the head, and where the seat abuts against another part of the bone anchoring device to restrict movement of the seat back towards the insertion position; and

wherein the bone anchoring device is further adjustable to lock the head relative to the receiving part body.

2 . The bone anchoring device of claim 1 , wherein the seat is expandable.

3 . The bone anchoring device of claim 2 , wherein when the seat is at the pre-locking position, the seat is restricted from expanding to restrict the head from being removed from the receiving part body through the opening.

4 . The bone anchoring device of claim 1 , wherein the receiving part further comprises a rod engaging portion with a rod contacting surface configured to extend into the channel of the receiving part body to contact the rod.

5 . The bone anchoring device of claim 4 , wherein the seat and the rod engaging portion are movable together in the receiving part body.

6 . The bone anchoring device of claim 4 , wherein the seat and the rod receiving portion are formed as respective parts of a monolithic pressure element.

7 . The bone anchoring device of claim 1 , wherein when the seat is at the pre-locking position and the head is held in the seat, a frictional force is configured to be exerted on the head to temporarily hold an angular position of the head relative to the receiving part body.

8 . A bone anchoring device comprising:

a bone anchoring element comprising a shaft and a head;

a receiving part for receiving a rod for coupling the rod to the bone anchoring element, the receiving part comprising:

a receiving part body having a first end, a second end, a channel at the first end for receiving the rod, an engagement surface for engagement with a separate closure element for locking the rod in the channel, an accommodation space for accommodating the head of the bone anchoring element, and an opening at the second end sized for inserting the head therethrough into the accommodation space; and

a seat insertable through the opening of the receiving part body and positionable at least partially in the accommodation space to engage and hold the head in the accommodation space;

wherein when the seat is in the receiving part body, the head of the bone anchoring element is insertable past the opening of the receiving part body to the seat;

wherein the seat is adjustable to a pre-locking position to restrict the head from being removed from the receiving part body through the opening, where the seat is pivotable together with the receiving part body relative to the head, and where the seat is configured to be held at the pre-locking position while the channel for the rod is vacant or unobstructed; and

wherein the bone anchoring device is further adjustable to lock the head relative to the receiving part body.

9 . The bone anchoring device of claim 8 , wherein the seat is expandable.

10 . The bone anchoring device of claim 9 , wherein when the seat is at the pre-locking position, the seat is restricted from expanding to restrict the head from being removed from the receiving part body through the opening.

11 . The bone anchoring device of claim 8 , wherein the receiving part further comprises a rod engaging portion with a rod contacting surface configured to extend into the channel of the receiving part body to contact the rod.

12 . The bone anchoring device of claim 11 , wherein the seat and the rod receiving portion are formed as respective parts of a monolithic pressure element.

13 . A bone anchoring device comprising:

a bone anchoring element comprising a shaft and a head;

a receiving part for receiving a rod for coupling the rod to the bone anchoring element, the receiving part comprising:

a receiving part body having a first end, a second end below the first end, a channel at the first end for receiving the rod, an accommodation space for accommodating the head of the bone anchoring element, and an opening at the second end sized for inserting the head therethrough into the accommodation space; and

a seat insertable through the opening of the receiving part body and positionable at least partially in the accommodation space to engage and hold the head in the accommodation space;

wherein when the head of the bone anchoring element and the seat are in the receiving part body, the seat is movable downwardly to a pre-locking position to restrict the head from being removed from the receiving part body through the opening, where the seat is pivotable together with the receiving part body relative to the head, and where an engagement between the seat and another surface of the receiving part that is positioned axially lower than a bottom of the channel of the receiving part body restricts upward movement of the seat away from the pre-locking position; and

wherein the bone anchoring device is further adjustable to lock the head relative to the receiving part body.

14 . The bone anchoring device of claim 13 , wherein the seat is expandable.

15 . The bone anchoring device of claim 14 , wherein when the seat is at the pre-locking position, the seat is restricted from expanding to restrict the head from being removed from the receiving part body through the opening.

16 . The bone anchoring device of claim 13 , wherein the receiving part further comprises a rod engaging portion with a rod contacting surface configured to extend into the channel of the receiving part body to contact the rod.

17 . The bone anchoring device of claim 16 , wherein the seat and the rod receiving portion are formed as respective parts of a monolithic pressure element.

18 . The bone anchoring device of claim 16 , wherein the rod contacting surface of the rod engaging portion forms a U-shaped recess with an axial depth that is less than half of a greatest width of the U-shaped recess.

19 . The bone anchoring device of claim 13 , wherein the seat is further configured to assume an insertion position where the head of the bone anchoring element is insertable through the opening into the receiving part body, and wherein the seat is movable downwardly from the insertion position to the pre-locking position.

20 . The bone anchoring device of claim 13 , wherein the seat engages a surface of the receiving part body at the pre-locking position to restrict the upward movement of the seat.