Coupling device for coupling a rod to a bone anchor

A coupling device for coupling a rod to a bone anchor, the coupling device comprising:

• a receiving part configured to receive a head of the bone anchor, the receiving part having a first end and a second end, a central axis extending through the first end and the second end, and two legs defining a recess at the first end for receiving the rod;
• a pressure member positionable in the receiving part, the pressure member comprising a head engaging surface configured to exert pressure on an inserted head;
• and
• an actuating member separate from the receiving part and the pressure member and configured to extend laterally through one of the two legs while remaining completely spaced apart from the other one of the two legs, the actuating member comprising an engagement surface configured to engage the pressure member;
• wherein when the engagement surface of the actuating member is at a first axial position located at a first distance from the first end of the receiving part, the pressure member is configured to assume a non-locking position in which the head is pivotable relative to the receiving part;
• and
• wherein when the engagement surface is moved axially relative to the central axis from the first axial position to a second axial position located at a second distance from the first end of the receiving part that is different from the first distance, the pressure member is configured to move relative to the actuating member to a locking position in which an angular position of the head is locked relative to the receiving part.

A coupling device for coupling a rod to a bone anchor, the coupling device comprising:

• a receiving part configured to receive a head of the bone anchor, the receiving part having a first end and a second end, a central axis extending through the first end and the second end, two legs defining a recess at the first end for receiving the rod, and an accommodation space at the second end for accommodating the head;
• a pressure member positionable in the receiving part, the pressure member comprising a head engaging surface movable along the central axis relative to the receiving part to adjust a pressure exerted on an inserted head;
• and
• an actuating member separate from the receiving part and the pressure member that comprises an engagement surface configured to engage the pressure member;
• wherein the actuating member is rotatable around an axis of rotation that is angled relative to the central axis to move the engagement surface axially from a position closer to the first end of the receiving part to a position farther away from the first end of the receiving part for adjusting the pressure member from a non-locking position where the head is pivotable relative to the receiving part to a locking position where an angular position of the head is locked relative to the receiving part.