1. Luftsichel sign The American Journal of Medicine
David Isbell, MD, Daniel Grinnan, MD, Manesh R. Patel, MD 
The American Journal of Medicine 
Volume 112, Issue 8, Pages (June 2002)
DOI: /S (02)

2. Figure 1
Posterior-anterior chest radiograph. Note the presence of air-containing lung above the aortic notch. The collapsed left upper lobe obscures the inferior border of the aortic notch.
The American Journal of Medicine  , DOI: ( /S (02) )

3. Figure 2
Lateral chest radiograph. Note the expanded lower lobe pushing the collapsed upper lobe against the chest wall.
The American Journal of Medicine  , DOI: ( /S (02) )