A flexible fiberoptic endoscope has an insertion member with a distal end portion split longitudinally into a plurality of independently operable working segments each provided with at least one longitudinally extending working channel. Visualization optics are provided in the working segments or a separate central segment surrounded by the working segments. A sheath temporarily joins the working segments to one another during an introduction procedure. The sheath is removed upon insertion of the endoscope, so that the working segments may be/separated from one another and independently maneuvered via proximal control heads to facilitate the performance of an endoscopic surgical procedure.