Simultaneous Cineradiographic and Kymographic Studies of Human Gastric Antral Motility

¹ From the Section of Physiology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota

Simultaneous cineradiographic and balloon-photokymographic records of gastric antral motility have been obtained in 19 healthy human subjects. Both type I and type II waves in the balloon-kymographic records have been shown to be annular contractions which invariably progress over the antrum toward the pylorus in a peristaltic manner. The two types of waves differ mainly in size in both balloon and cineradiographic recordings. The type I waves in the balloon-kymographic records are due to small annular constrictions produced apparently by contraction of only a part of the circularly disposed muscle fibers of the wall of the stomach. Type II waves in the balloon records are, on the other hand, due to annular constrictions of the entire thickness of the gastric wall, produced presumably by powerful contraction of most, if not all, of the circularly disposed muscle fibers of the stomach wall. About 70% of type II waves propelled barium sulfate through the pylorus into the duodenum, while only 17% of the type I waves had this action. It is concluded that the major function of type II contractions is propulsion, while their secondary function is mixing, and that mixing is the primary action of the type I contractions and propulsion is secondary. Failure of barium sulfate to pass through the pylorus when a contraction passed over the antrum occurred either when the pylorus failed to relax or when the contraction faded out just before reaching the pylorus.