A coupling device includes a first coupling body configured to be coupled to a first bone anchor, a second coupling body configured to be coupled a second bone anchor, and a connection device comprising a first connection member connectable to the first coupling body, a second connection member connectable to the second coupling body, and a length adjustment member positionable between and insertable at least partially into each of the first and second connection members. The first and second connection members are movable relative to the length adjustment member. The length adjustment member can be actuated in a first direction to increase a distance between the first connection member and the second connection member, and in a second direction different from the first direction to decrease the distance between the first connection member and the second connection member.
