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August 14, 1981

'Rocker-Bottom Thymus'A New Sign of Pneumomediastinum in the Neonate

JAMA. 1981;246(7):770-771. doi:10.1001/jama.1981.03320070054027

THE OCCURRENCE of pneumomediastinum and pneumothorax in the neonate is relatively common. Pneumomediastinum is secondary to alveolar rupture with dissection of air along the pulmonary interstitium into the mediastinum.1 This condition usually causes little or no respiratory distress. The classic configuration of pneumomediastinum is caused by elevation of the thymic lobes by air loculated within the anterior mediastinum. Several descriptive terms, including the "angel-wing" or "spinnaker sail" thymus, are well known.2 Mediastinal air may also enter the subpleural space causing the "extrapleural air sing."3 This article describes a previously unreported configuration of the thymus in pneumomediastinum. This should not be confused with more serious abnormalities such as mediastinal masses, anomalous vessels, or other pathological structures.

Report of Cases 

Case 1.—  A 2,200-g infant was born after a full-term gestation and delivery. The infant was referred to this hospital after experiencing mild respiratory distress, and a chest roentgenogram