Patent ID: 7918783

Claim:
An endoscopic instrument assembly, comprising: an endoscope defining a working channel therein; an inner surface defined by the working channel, wherein the inner surface has a first portion having a substantially circular cross-sectional shape, a second portion having a substantially circular cross-sectional shape, and a rotatable lock portion including an inner perimeter defined by the inner surface and having a non-circular cross-sectional shape, the lock portion being disposed between the first portion and the second portion, wherein the first portion, the lock portion, and the second portion extend in series along a length of the working channel; an endoscopic instrument slidably disposed in the working channel, the endoscopic instrument having an outer surface with a key portion including an outer perimeter defined by the outer surface and having a non-circular cross-sectional shape; and wherein the non-circular cross-sectional shape of the inner perimeter is substantially the same as the non-circular cross-sectional shape of the outer perimeter.