The attempt to exhale with the mouth, nose and glottis (back of the tongue) closed to produce pressure on the tympanic membranes (ear drums) if the eustachian tubes are not obstructed. This is the method divers will use to clear their ears, to equalize the pressure on both sides of the ear drum. If the patient can't produce enough pressure himself, the doctor might try using a Politzer bag. Named for Antonio Maria Valsalva an Italian anatomist.