This patient has collapse of the entire left upper lobe, including the lingula. On the PA film, this projects as a hazy opacity over much of the upper left hemithorax. The lateral view shows the classic”pancake” opacity filling the retrosternal air space. There is mild elevation of the left hemidiaphragm; other indirect signs are not well seen here. This film also demonstrates “silhouetting” of the aortic knob and upper left heart border.
