Trocar cannula for inserting instruments into body cavities has duck-bill valve with oval body of larger diameter than interior of valve chamber

摘要

The cannula consists of an insertion tube with a valve chamber (3) at its proximal end containing a duck-bill valve (4) of an elastic material. The valve has an oval-section tubular body (5) and a tip with two oblique flat surfaces (7) and a slit (8). It its rest state the body (5) of the valve in line with the transverse slit is of greater diameter than the interior of the valve chamber.