A reinforced arthroscope comprising external ribs to provide for a number of separate fluid channels, such as inflow, outflow and interstitial tissue drainage, when the arthroscope is slipped into a disposable external sheath. The arthroscope is constructed to be sufficiently rigid so as to penetrate and move within a joint without damaging the rod optics inside. The externality of the arthroscope channels allow for cleaning and sterilizing the scope between uses.