Abstract: A fully enclosed detent hinge mechanism for a foldable bathroom shower seat or other hinged device, comprising a hinge housing; a rotatable element rotatable received in the hinge housing and connectable or connected to a hingably movable part of the hinged device for angular displacement therewith; and a detent mechanism which releasably retains the hingably movable part of the hinged device when in a raised, condition. The detent mechanism includes a first detent part located on the hinge housing and a second detent part located on the rotatable element and which is cooperable with the first detent part to prevent or substantially prevent unintentional movement of the rotatable element in the hinge housing. One of the first and second detent parts includes an integrally formed cantilever arm which is cooperable with a remaining said one of the first and second detent parts to prevent or substantially prevent unintentional movement of the rotatable element in the hinge housing.