[The technique and importance of examination of the function of the maxillary sinus ostium (author's transl)].

A method of measuring the patency of the maxillary sinus ostium under physiological conditions is described. By means of a rhinomanometer passed into the ostium the air-pressure within the sinus with artificially induced pressure changes can be studied. Accurate assessment regarding prognosis and the need to perform sinus surgery can thus be made.