(val‵sal'vă )

Antonio Maria Valsalva, Italian anatomist, 1666–1723.

V. maculopathy Macular bleeding due to a sudden increase in abdominal or chest pressure. It causes sudden central visual loss that often resolves spontaneously.

V. maneuver An attempt to forcibly exhale with the glottis, nose, and mouth closed. This maneuver causes increased intrathoracic pressure, slowing of the pulse, decreased return of blood to the heart, and increased venous pressure. If the eustachian tubes are not obstructed, the pressure on the tympanic membranes also will be increased. When this maneuver is done with just the glottis closed, only intrathoracic pressure will increase. This maneuver may be helpful in converting supraventricular tachycardias to normal sinus rhythm (it works between 15 and 50% of the time) or in clearing ears that have become blocked during a descent from a high altitude.

SEE: Müller maneuver; Toynbee maneuver.

V. sinuses The three dilatations in the wall of the ascending aorta behind the three flaps of the aortic semilunar valve.