Abstract: A fiber optic endoscope has a shaft with a varying outer diameter. The distal end of the shaft is sufficiently small in outside diameter for maneuvering it through various body canals, and is useful in dilating body orifices to allow more proximal, longer-diameter portions of the shaft to penetrate. The endoscope shaft changes in thickness and is preferably in stages of different constant outside diameter. A flexible tip portion at the distal end of the shaft which is controllable from the endoscope handle may be included. Transitions between adjacent stages are smooth to provide a gradual transition between stages. The endoscope outer shaft is preferably made from a one-piece structure, portions of which are reduced in outside diamter to provide the different stages of the endoscope shaft.

Abstract: A fiber optic endoscope has a shaft with a varying outer diameter. The distal end of the shaft is sufficiently small in outer diameter for maneuvering it through various body canals, while the overall length of the shaft is rigid enough to allow axial and rotational translation of the shaft when controlled manually from a handle at the proximal end. The endoscope shaft may be n stages of different outer diameter or it may be uniformly tapered along its entire length. Either a step-tapered or a uniformly tapered version may include a flexible tip portion at the distal end of the shaft which is controllable from the endoscope handle.