[Examination of patency of ostium by measurement of air flow in the maxillary sinus (author's transl)].

The patency of the maxillary ostium can investigated by measurement of velocity and of presure difference with a new equipment of hot film anemometry and by strain gauges. This studies were performed during sinuscopy. The values are registered on a way-time recorder. The measurement of velocity in the maxillary sinus is more preferable than the measurement of pressure because we need no extraantal point of reference pressure: nose-sinus: difference pressure: sinus atmosphere. Both methods, the measurement of air flow and pressure difference, can proof the patency of the maxillary ostium. Examples are given from open partial patent ostium and from obstructed one.