An orientation apparatus for a tibial resection guide comprising or consisting of a probing device having: - a helical-shaped or gear-rack shaped adjustment element, - a feeler which is held on the adjustment element, - a helical-wheel shaped or gear-shaped setting element which is engaged with or coupled to the adjustment element in order to move the feeler via the adjustment element by manual actuation of the setting element, - a scale carrier coupled to the feeler or the adjustment element and extending along the adjustment element, wherein the scale carrier indicates a current position of the feeler, preferably with respect to the setting element, with reference to a marking on the setting element, on the feeler or on the adjustment element, - at least one first latch or stop member and - at least one second latch or stop member, - wherein - the first latch or stop member and/or the second latch or stop member is spring-elasticly yielding or mounted in a spring-elasticly yielding manner, so that - the first and the second latch or stop member (118, 120), upon actuation of the setting element in a specific relative rotational position or within a specific relative position range between the scale carrier and the setting element, the first latch or stop member and/or the second latch or stop member deflects the respective other stop member in a spring-elastic manner, and in that - upon further actuation of the setting element, the first and/or second stop member (118, 120) springs back, preferably abruptly, into a latch or stop engagement with each other, characterized in that - the at least one first latch or stop member is formed on the setting element, and the at least one second latch or stop member is formed on the scale carrier or is formed by the scale carrier. - a helical-shaped or gear-rack shaped adjustment element, - a feeler which is held on the adjustment element, - a helical-wheel shaped or gear-shaped setting element which is engaged with or coupled to the adjustment element in order to move the feeler via the adjustment element by manual actuation of the setting element, - a scale carrier coupled to the feeler or the adjustment element and extending along the adjustment element, wherein the scale carrier indicates a current position of the feeler, preferably with respect to the setting element, with reference to a marking on the setting element, on the feeler or on the adjustment element, - at least one first latch or stop member and - at least one second latch or stop member, - wherein - the first latch or stop member and/or the second latch or stop member is spring-elasticly yielding or mounted in a spring-elasticly yielding manner, so that - the first and the second latch or stop member (118, 120), upon actuation of the setting element in a specific relative rotational position or within a specific relative position range between the scale carrier and the setting element, the first latch or stop member and/or the second latch or stop member deflects the respective other stop member in a spring-elastic manner, and in that - upon further actuation of the setting element, the first and/or second stop member (118, 120) springs back, preferably abruptly, into a latch or stop engagement with each other, characterized in that - the at least one first latch or stop member is formed on the setting element, and the at least one second latch or stop member is formed on the scale carrier or is formed by the scale carrier.