This patient has suffered complete collapse of the right middle lobe. Note the opaque, atelectatic right middle lobe projecting over the mid right hemithorax. The collapsed right middle lobe also demonstrates the “silhouette” sign; in this case, part of the adjacent right heart border is obscured by the atelectatic lobe. The lateral view demonstrates the flat, “pancake”-shaped right middle lobe. The minor fissure (black arrow) and major fissure (green arrow) approximate as the intervening lung tissue collapses.
