Infra-azygous pneumomediastinum versus pulmonary ligament air collection: CT evaluation.

A full-term infant developed a large collection of air posteriorly in the thorax. Computed tomography showed the anatomical distribution of this extraventilatory air and although, it did not conclusively differentiate between infra-azygous pneumomediastinum and a pulmonary ligament air collection, inappropriate needle aspiration of the air was avoided.