Abstract: A coupling device for coupling a rod to a bone anchor includes a receiving part having first and second ends, a central axis, and two legs defining a recess at the first end for receiving the rod, a pressure member configured to exert pressure on an inserted head, and an actuating member with an engagement surface configured to engage the pressure member. When a first portion of the actuating member moves axially in a first direction, the engagement surface is configured to move from a first axial position to a second axial position to adjust the pressure member from a non-locking position where the head is pivotable to a locking position where the head is locked. When a second portion of the actuating member moves in the first direction, the pressure member is adjusted from the locking position back to the non-locking position.

Abstract: A system for coupling a rod to bone includes first and second bone anchors that are different from one another and a coupling device including a receiving part with a central axis and a head receiving portion for interchangeably receiving a head of either the first or second bone anchors, and a pressure member configured to exert pressure on the head of either the first or second bone anchors when the head is in the receiving part to clamp the inserted head at a particular position relative to the receiving part. The coupling device includes a restraining surface configured to cooperate with the first bone anchor to restrict pivoting of the first bone anchor to a single plane. The coupling device is configured to cooperate with the second bone anchor to restrict pivoting of the second bone anchor differently than the restricted pivoting of the first bone anchor.

Abstract: A bone anchoring device includes a receiving part including a rod receiving portion with a first end, a second end, and a U-shaped recess for receiving a rod, the recess defining two free legs, and a head receiving portion at the second end for introducing and clamping the head, and a locking ring configured to be arranged around the head receiving portion, the locking ring including an engagement structure for engagement with a tool, the engagement structure defining a width of the locking ring that is greater than a greatest width of the rod receiving portion, wherein the locking ring can assume a locking position exerting a greatest compressive force on the head receiving portion of the receiving part to lock an inserted head, and wherein the locking ring is movable out of the locking position towards the first end of the rod receiving portion.

Abstract: A bone anchoring device includes a receiving part having a central axis, two legs defining a recess for receiving a rod, and a head receiving portion that is at least partially expandable and having an opening for inserting and pivotably holding a head of a bone anchoring element therein, and a locking ring mountable around the head receiving portion in an axial direction while a rotational orientation of the locking ring relative to the receiving part remains constant. When the locking ring is around the head receiving portion, the locking ring is rotatable around the central axis from a first rotational orientation to a second rotational orientation where a compressive force exerted by the locking ring on the head receiving portion is greater than at the first rotational orientation.

Abstract: A coupling device includes a receiving part with an accommodation space for accommodating a head of a bone anchoring element, an opening, and a recess forming two legs for receiving a rod, and a pressure member arranged at least partially in the accommodation space. The pressure member is adjustable from a first configuration where a topmost end of the pressure member is at a first axial position and the head is pivotable in the accommodation space to a second configuration where the topmost end of the pressure member is at a second axial position below the first axial position and the pressure member provisionally lock the heads. At the second configuration, a latching connection is formed to prevent the pressure member from being adjusted back towards the first configuration. The latching connection is releasable to adjust the pressure member from the second configuration back towards the first configuration.

Abstract: A bone anchoring device includes a receiving part with a rod receiving portion having a first end, a second end, a recess for the rod, an outer surface, and a first engagement structure on the outer surface that extends farther radially outwardly than other parts of the rod receiving portion, and a flexible head receiving portion for inserting and clamping the head. The bone anchoring device also includes a locking ring configured to be arranged around the head receiving portion for locking the head, the locking ring having an outer surface and a second engagement structure on the outer surface that extends farther radially outwardly than the outer surface of the rod receiving portion. The engagement structures are configured to be engaged by an instrument to move the locking ring from a locking position to a position where the inserted head is pivotable.

Abstract: A coupling device for coupling a rod to a bone anchor includes a receiving part having first and second ends, a central axis, and two legs defining a recess at the first end for receiving the rod, a pressure member configured to exert pressure on an inserted head, and an actuating member with an engagement surface configured to engage the pressure member. When a first portion of the actuating member moves axially in a first direction, the engagement surface is configured to move from a first axial position to a second axial position to adjust the pressure member from a non-locking position where the head is pivotable to a locking position where the head is locked. When a second portion of the actuating member moves in the first direction, the pressure member is adjusted from the locking position back to the non-locking position.

Abstract: A bone anchoring device for coupling a rod to a bone includes a bone anchoring element with a head and a shank, a receiving part having an accommodation space for pivotably holding the head of the bone anchoring element, and a recess for receiving the rod, a pressure member for exerting pressure on the head in the receiving part, and a separate locking member movable relative to the receiving part from a first position where the head of the bone anchoring element is insertable into the accommodation space, to a second position where the locking member directly engages and exerts pressure on the head to hold a position of the head relative to the receiving part.

Abstract: A bone anchoring device includes a receiving part having a central axis, two legs defining a recess for receiving a rod, and a head receiving portion that is at least partially expandable and having an opening for inserting and pivotably holding a head of a bone anchoring element therein, and a locking ring mountable around the head receiving portion in an axial direction while a rotational orientation of the locking ring relative to the receiving part remains constant. When the locking ring is around the head receiving portion, the locking ring is rotatable around the central axis from a first rotational orientation to a second rotational orientation where a compressive force exerted by the locking ring on the head receiving portion is greater than at the first rotational orientation.

Abstract: A coupling device for use with a bone anchoring element includes a receiving part having first and second ends, a longitudinal axis, and a coaxial passage, and a pressure member having a first portion and an expandable portion connected axially to the first portion forming a seat for the head. The pressure member is movable to a position where the receiving part acts on the expandable portion to clamp the head in the seat. The seat can be asymmetric relative to the longitudinal axis while a central axis of the first portion is coaxial with the longitudinal axis, such that the seat facilitates pivoting of the bone anchoring element in a first direction to a first maximum angle and in an opposite direction to a second maximum angle smaller than the first maximum angle.

Abstract: A bone anchoring device includes a receiving part with a recess for receiving a rod and a flexible head receiving portion for pivotably holding a head of a bone anchoring element, a pressure member configured to exert pressure on the head when the head is held in the head receiving portion, and a clamping ring positionable around the head receiving portion and movable from a first position where the head is pivotable relative to the receiving part, to a second position where the clamping ring exerts a radial force on the head receiving portion to lock the head relative to the receiving part. When the clamping ring is at the first position, the clamping ring abuts the receiving part to restrict upward movement, while a surface of the clamping ring that faces upwards is exposed for engaging an instrument to move the clamping ring to the second position.

Abstract: A coupling device includes a receiving part with an accommodation space for accommodating a head of a bone anchoring element, an opening, and a recess forming two legs for receiving a rod, and a pressure member arranged at least partially in the accommodation space. The pressure member is adjustable from a first configuration where a topmost end of the pressure member is at a first axial position and the head is pivotable in the accommodation space to a second configuration where the topmost end of the pressure member is at a second axial position below the first axial position and the pressure member provisionally lock the heads. At the second configuration, a latching connection is formed to prevent the pressure member from being adjusted back towards the first configuration. The latching connection is releasable to adjust the pressure member from the second configuration back towards the first configuration.

Abstract: A coupling device for use with a bone anchoring element includes a receiving part having first and second ends, a longitudinal axis, and a coaxial passage, and a pressure member having a first portion and an expandable portion connected axially to the first portion forming a seat for the head. The pressure member is movable to a position where the receiving part acts on the expandable portion to clamp the head in the seat. The seat can be asymmetric relative to the longitudinal axis while a central axis of the first portion is coaxial with the longitudinal axis, such that the seat facilitates pivoting of the bone anchoring element in a first direction to a first maximum angle and in an opposite direction to a second maximum angle smaller than the first maximum angle.

Abstract: A bone anchoring device includes a receiving part with a recess for receiving a rod and a flexible head receiving portion for pivotably holding a head of a bone anchoring element, a pressure member configured to exert pressure on the head when the head is held in the head receiving portion, and a clamping ring positionable around the head receiving portion and movable from a first position where the head is pivotable relative to the receiving part, to a second position where the clamping ring exerts a radial force on the head receiving portion to lock the head relative to the receiving part. When the clamping ring is at the first position, the clamping ring abuts the receiving part to restrict upward movement, while a surface of the clamping ring that faces upwards is exposed for engaging an instrument to move the clamping ring to the second position.

Abstract: A bone anchor includes a shank with a first end, an opposite second end, and a longitudinal axis. The shank includes a core, a thread that extends in a helix around the core and that has a lower flank directed towards the first end and an upper flank directed towards the second end, wherein the upper flank and the lower flank define a first cross-sectional thread shape, and an additional thread structure including a recess that extends together with part of the thread in the helix around the core. The thread and the additional thread structure together define a second cross-sectional thread shape different from the first cross-sectional thread shape. An axial length of the portion of the thread that has only the first cross-sectional thread shape is greater than an axial length of the entire portion of the thread that includes the second cross-sectional thread shape.

Abstract: A polyaxial bone anchoring device includes a receiving part with a rod receiving portion defining a recess for receiving a rod, and a head receiving portion with a wall that defines an accommodation space for accommodating a head of an anchoring element, and a locking member positionable at least partially around the head receiving portion and movable from a first position where the head can pivot in the accommodation space to a second position where an angular position of the head is locked. The wall of the head receiving portion further defines at least one cavity in communication with the accommodation space that reduces a radial thickness of at least part of the wall located between the accommodation space and the locking member, and at least part of the cavity is separated radially from the accommodation space by a portion of the wall.

Abstract: A bone anchoring device includes a receiving part including a rod receiving portion with a first end, a second end, and a U-shaped recess for receiving a rod, the recess defining two free legs, and a head receiving portion at the second end for introducing and clamping the head, and a locking ring configured to be arranged around the head receiving portion, the locking ring including an engagement structure for engagement with a tool, the engagement structure defining a width of the locking ring that is greater than a greatest width of the rod receiving portion, wherein the locking ring can assume a locking position exerting a greatest compressive force on the head receiving portion of the receiving part to lock an inserted head, and wherein the locking ring is movable out of the locking position towards the first end of the rod receiving portion.

Abstract: A bone anchoring device includes an anchoring element having a shank for anchoring in a bone and a head, a receiving part configured to pivotably receive the head, and a pressure member for exerting pressure on the head to clamp the head in the receiving part, the pressure member defining a head receiving recess for pivotably holding at least a portion of the head therein and comprising a first surface configured to restrict removal of the head from the head receiving recess. The head includes a first position indication structure configured to engage a second position indication structure of the bone anchoring device when the shank assumes a first angular position relative to the receiving part. The first and second position indication structures disengage from one another when the shank is moved out of the first angular position to a different angular position.

Abstract: A polyaxial bone anchoring device includes a receiving part with a rod receiving portion defining a recess for receiving a rod, and a head receiving portion with a wall that defines an accommodation space for accommodating a head of an anchoring element, and a locking member positionable at least partially around the head receiving portion and movable from a first position where the head can pivot in the accommodation space to a second position where an angular position of the head is locked. The wall of the head receiving portion further defines at least one cavity in communication with the accommodation space that reduces a radial thickness of at least part of the wall located between the accommodation space and the locking member, and at least part of the cavity is separated radially from the accommodation space by a portion of the wall.

Abstract: An anchoring element includes a shank for anchoring to bone and a separate head that is connectable to the shank. The head has an exterior surface with a spherically-shaped section and an unthreaded tool engagement surface that is engageable with a drive tool when the head and the shank are connected to one another.