The present invention is directed to a device including an inner cannula having one or more wings or leaflets attached to one end thereof. The wings or leaflets can be cut to length or shaped to facilitate holding the operative field open for optimal visualization and the use of surgical instruments. A shorter, outer cannula is fitted over the inner cannula and a flange attached to the outer cannula is moved from a closed position in which the wings are covered by the inner surface of the cannula or to an open, deployed position in which the wings are opened. The outer cannula may be textured or shaped to aid in holding the desired position. The device also includes a dam or barrier at the end or other convenient location in the inner cannula to control the flow of air or fluids in the cannula as to make it useful in arthroscopic or endoscopic surgery of all types. The wings or leaflets can have mating tapered tips that joint into a single tip when closed or an optional trocar to ease insertion into the desired body cavity. The design allows for manufacture at almost any size to make the device useful in the widest of surgical applications and in all joint or body cavities large or small.