THE SPONTANEOUS MOTILITY OF THE PYLORIC SPHINCTER AND ITS RELATION TO GASTRIC EVACUATION: THE "PYLORIC DIAGRAPH"

Abstract

Studies of the pyloric sphincter motility were made in trained dogs with the "Pyloric diagraph," a device which permits continuous detns. of the extent of sphincter closure, but does not involve a foreign body in the lumen. It was thus detd. that the quiescent sphincter normally is in the relaxed state. The active sphincter normally exhibits cyclic activity and is relaxed during more than half of each cycle. Sphincter opening is a characteristic phase of the cyclic activity, not fundamentally the result of a passive stretching produced by material propelled from an adjacent portion of the gut lumen. The time relations of pyloric sphincter contraction to the other aspects of gastric evacuation show that the sphincter does not function in the ordinary sense as the "keeper of the gate." No evacuation occurs while the sphincter is opening or immediately thereafter. The sphincter is open during much-of the evacuation period but closes as evacuation is terminating.