What radiographic signs are consistent with pneumothorax?

• A. Decreased thoracic lucency with bronchial markings
• B. Increased thoracic lucency, lung collapse, reduced pulmonary markings, and possible mediastinal shift
• C. Cardiac silhouette enlargement
• D. Diffuse miliary nodularity

Answer: (B)

Air in the pleural space increases radiographic lucency on the affected side and causes the lung to collapse, with fewer markings seen beyond the visceral pleural line. This combination—greater thoracic lucency, lung collapse, reduced pulmonary markings, and, if the pneumothorax is under tension, mediastinal shift—is the classic pattern of pneumothorax on a chest radiograph. The other signs listed point to different conditions: decreased lucency with persistent bronchial markings isn’t typical of a pneumothorax; an enlarged cardiac silhouette suggests cardiomegaly; diffuse miliary nodularity indicates disseminated disease like miliary infection or inflammation.