ABSTRACT
Anal manometry supplies objective information about internal and external anal sphincter function. Anal manometry is useful in the evaluation of incontinence, constipation, and location of sphincteric injuries. Anal manometry done in a laboratory setting does not take into account diurnal variations or periodic anal sphincter activity. The balloon and water perfusion methods of anal manometry require pressure strain gauge transducers which convert changes in volume and resistance to flow into electrical signals. Anal resting pressure is determined by placing a pressure measuring probe within the rectum. The internal balloon is surrounded by the internal anal sphincter and the external balloon is surrounded by the superficial external anal sphincter. Water systems need to be zeroed at the anal verge and care must be taken to remove all air bubbles from the system. The polyvinyl catheter is inserted into the rectum and withdrawn through the anal canal in either a continuous or stationary pullout technique to determine resting and squeeze pressures.
