Also found in: Acronyms.
a one-way speaking valve for use with tracheostomy tubes. Its normal position at rest is closed, so that it is open only during inhalation and closes during exhalation, allowing air to pass through the vocal folds for phonation.
Pa·ssy-Mu·ir valve(pas'ē-myū'ĭr valv)
One-way valvular device to facilitate ventilation and speech in patients who have undergone tracheotomy.