Instrument for removing a foreign substance from the body cavity of human being

An instrument inserted through a channel of an endoscope for trapping a foreign substance, such as a polyp or stone, and removing it outside of the body cavity of a human being, comprising:

• an elongated flexible instrument body having an outer tube, an inner tube, and a control wire axially and slidably inserted into the inner tube and having a hook member at one end thereof, said hook member having a cutout at its side;
• trap means having a loop-like anchoring member releasably anchored within said cutout of the hook member, said anchoring member being detachable from the cutout of the hook member when the hook member is moved out of the inner tube, thereby releasing the trap means from the instrument body;
• a ring member slidably moved and fitted over the trap means for squeezing the same;
• and
• a supporting wire one end of which supports the trap means released from the instrument body, the other end of which passes through the channel of the endoscope and extends outside thereof.