US Patent 9155679 Medical container and syringe

A syringe is provided with an inner tube which has at the tip thereof a mouth section through which liquid can enter and exit the inner tube; a bag body which is disposed inside the inner tube and is flexible and reversible; a gasket which is mounted to the tip of the inner tube; and an outer tube in which the inner tube is inserted together with the gasket so as to be movable in the axial direction. The syringe is configured in such a manner that, when liquid enters and exits through the mouth section, the bag body is reversed to change the volume of a containing space surrounded by the inner tube and the bag body.