A new method of measuring pressure is presented which serves to determine the opening pressures in organic sphincter areas and to investigate the behavior of the high-pressure zone and its susceptibility. By means of a pressure-measuring device which is introduced into the sphincter area, the opening pressure, which may be equated to the constant closing pressure, can be determined by known increases of pressure. The method is described in detail, and the use of this manometric procedure is demonstrated with reference to the lower esophageal sphincter.