[Morphological and functional changes in the closing sphincter of the lower esophagus after experimentally-induced...

Report of an experimental model of axial hiatal hernia in dogs, always combined with reflux (roentgenologic control). Using a new method of pressure measurement, the authors succeeded in proving the distention of the esophageal "sphincter". Morphologic investigations demonstrated, that in hernia the muscle fiber is no longer an apolar helical fiber, but runs nearly horizontally. The reduced susceptibility to pentagastrin is caused by diminished tension of the muscle fiber. The distal esophageal closing mechanism consequently seems to be a function of the whole organ and not of a hormonally regulated sphincter.