Atelectasis (pronounced at-uh-LEK-tuh-sis) is the term for a collapse of one or more areas in the lung. When you breathe in, your lungs fill up with air. This air travels to air sacs in your lungs (alveoli), where the oxygen moves into your blood.

Where is atelectasis most common?

Because the right middle lobe orifice is the narrowest of the lobar orifices and because it is surrounded by lymphoid tissue, it is the most common lobe to become atelectatic. This is referred to as right middle lobe syndrome.

Where does atelectasis occur?

Atelectasis (at-uh-LEK-tuh-sis) is a complete or partial collapse of the entire lung or area (lobe) of the lung. It occurs when the tiny air sacs (alveoli) within the lung become deflated or possibly filled with alveolar fluid. Atelectasis is one of the most common breathing (respiratory) complications after surgery.