from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Expiratory effort when the mouth is closed and the nostrils are pinched shut, which forces air into the eustachian tubes and increases pressure on the inside of the eardrum.
- n. Expiratory effort against a closed glottis, which increases pressure within the thoracic cavity and thereby impedes venous return of blood to the heart.
After Antonio Maria Valsalva (1666-1723), Italian anatomist.(American Heritage® Dictionary of the English Language, Fourth Edition)