The gatekeeper a gaping — long or its continuous relaxation, arises in connection with a prevalence of process of relaxation over reduction. Radiological expansion of a shadow of a gleam of the gatekeeper who is freely passing a contrast agent is defined. Sometimes the gaping of the gatekeeper is followed by retrograde intake of contrast medium from a duodenum in a stomach. The reasons causing the gatekeeper's gaping: the functional disturbances connected with the pathological reflexes proceeding from a stomach and adjacent bodies. Diseases at which the gatekeeper's gaping is noted: the duodenitis, a duodenum ulcer, a perigastritis, a periduodenitis, gepatokholetsistit, a tumor of a stomach or a head of a pancreas with the phenomena of a secondary stenosis of a duodenum, arteriomesenteric impassability. It is distinguished at roentgenoscopy, a X-ray analysis with use of a contrast agent and pharmacological drugs, X-ray cinematographies in various projections in vertical and horizontal position of investigated.