Respiratory Residual Volume – The amount of air left in the lungs after maximum exhalation

(Pronounced ruh-zid-yoo-uhl)

To remember what residual volume means use the following mnemonic:

The residue you'll (residual) see in the bottom of a jar can be compared to the air left in the lungs after maximum exhalation.

Residual volume is the amount of air that remains in the lungs after a person has exhaled as much as they can. It is necessary for the lungs to retain some air to maintain proper function, shape and strength. Certain lung diseases can lead to increased residual volume, which in turn can lead to difficulty breathing and reduced lung capacity.