[Methodologic studies of manometry of the rectum].

For the purpose of an experimental study in which the three different types of pressure catheters most commonly used in anorectal manometry were compared, a Starling-resistance could be established. Under equal conditions the pressures could be changed in this resistance and the data obtained by using a membrane-catheter, an open-tip and an open-side-catheter were compared among one another and to the known ideal straight line. The open tip catheter measures the opening pressure and the recorded pressure does not necessarily reflect the pressure at the site of the tip hole. Because of its elastic and plastic characteristics, the membrane-catheter yielded the best results with prestretch of the membrane and with calibration before and after each study.