Figure 13. 7-year-old girl with right upper lobe atelectasis associated with localized pneumothorax. The patient had congenital hypertrophic cardiomyopathy. Anteroposterior radiograph shows a localized pneumothorax adjacent to the atelectatic right upper lobe, "pneumothorax ex vacuo". Note that the pneumothorax is bounded by the outline of the atelectatic upper lobe (arrowheads).