Presentation
Cough and desaturations on background of recent left lower lobe pneumonia and COPD.
Patient Data
Age: 80 years
Gender: Male
From the case:
Left lower lobe collapse
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Airspace opacification in the left lower zone, with loss of definition of the medial left hemidiaphragm. With this, a straight border is seen going from the diaphragm to the AP window. This is known as the "sail sign" and demonstrates left lower lobe collapse.
Case Discussion
Sail sign is a descriptive term for left lower lobe collapse. As the tissues lose aeration, the density of the lobe increases and collapses medially.