ICU Chest Films > Lung Processes > Atelectasis > Right Middle Lobe

Right Middle Lobe Atelectasis

Right middle lobe atelectasis may cause minimal changes on the frontal chest film. A loss of definition of the right heart border is the key finding. Right middle lobe collapse is usually more easily seen in the lateral view. The horizontal and lower portion of the major fissures start to approximate with increasing opacity leading to a wedge of opacity pointing to the hilum. Like other cases of atelectasis, this collapse may by confused with right middle lobe pneumonia.

Right middle lobe atelectasis is difficult to detect in the AP film (left). The lateral (right), though, shows a marked decrease in the distance between the horizontal and oblique fissures.

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