A pivot mechanism for guiding in rotation comprises a mobile element connected to a fixed element through flexible connections; with the flexible elements being configured to guide the mobile element according to a rotational movement in a plane, around a pivoting axis perpendicular to the plane; with each of the flexible connections comprising an intermediary junction provided with an expansion slot, the expansion slot being configured to expand during the rotation of the mobile element, so that the mobile element can pivot according to a second angular amplitude that is greater than a first angular amplitude achieved without said expansion slot; with the intermediary junctions being connected to one another by a coupling member; each of the coupling members being configured so as to prevent a movement out of the plane and a lateral movement in the plane of the mobile element. The pivot mechanism has a very high rotational amplitude.