Hinge (4) comprising at least one housing (6) formed in a first panel (2), and at least one rod (7) integral with a second panel (3) and rotationally mounted in the housing (6). According to the invention, the rod (7) is movable from a retracted position in which it is prevented from moving into the housing (6) when the two panels (2, 3) are in a correct mutual position, and a control element (9) movable from a release position to a locking position and adapted to cooperate with the rod (7) with the result that said rod is in the retracted and hinged positions when the control element (9) is in the release and locking positions, respectively.