Medical instrument

Claim 1

In a medical instrument having an insertion section including a tubular member that is insertable into a living body and an operating section which is operably connected to the tubular member of the insertion section for performing a medical activity through said insertion section; the improvement comprising: an injection molded insertion section tubular member formed entirely of an electrically insulating liquid crystal polymer, that increases in mechanical strength, in a unit area thereof, as a wall thickness of a wall of the insertion section tubular member decreases in thickness; said wall of said insertion section tubular member being a unitary structure formed entirely of the liquid crystal polymer and including a core layer of the liquid crystal polymer sandwiched between first and second skin layers of the liquid crystal polymer; said wall thickness of said wall of said insertion section tubular member being pre-selected to provide the insertion section tubular member with: (a) a mechanical strength sufficient to withstand a bending force produced when the insertion section tubular member is inserted into the living body; (b) a mechanical strength sufficient to prevent a collapse of the insertion section tubular member along a longitudinal axis thereof created by a pressure of the living body against a circumference of the insertion section tubular member; (c) a small outside diameter relative to a diameter of a body cavity of the living body into which said insertion section tubular member is insertable, for reducing trauma to the living body upon insertion of the insertion section tubular member into the body cavity; and (d) an inside diameter that enables a plurality of medical apparatus respectively having a preset maximum diameter to be moved from the operating sections through the insertion section tubular member.