Abstract: A incremental rotational displacement mechanism is provided. The mechanism includes a circular detent housing having a plurality of detents arranged along the circumference of the detent housing. A detent ring is positioned coplanar to and within the circumference of the detent housing. At least a portion of the at least one detent arm engages at least a portion of the detent housing. A handle may engage the detent ring, so that a force applied to the handle causes the detent ring to rotate with respect to the circular detent housing. The mechanism is suitable for a variety of applications, including endoscopic instruments.