Pneumothorax is defined as gas within the pleural space, with compression of adjacent lung. It can be small or large, spontaneous or due to penetrating trauma, and can be managed expectantly or with chest tube insertion. A tension pneumothorax is one where there is pressure buildup in the pleural space, usually due to leakage of air via a one-way valve. It requires immediate needle thoracostomy.

Case #1a. An early developing right pneumothorax. The apical extent of the pneumothorax is subtle.
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Case #1b. The pneumothorax above has become more prominent over the course of 6 hours.
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Case #2. Left apical pneumothorax.

Case #3. Partial collapse of right lung with question of leftward shift of cardiac silhouette.