Aortopulmonary window

The aortopulmonary window is a small space between the aortic arch and the pulmonary artery that is visible in the lateral chest radiograph. It contains the ligamentum arteriosum, the recurrent laryngeal nerve, lymph nodes, and fatty tissue. The space is bounded anteriorly by the ascending aorta, posteriorly by the descending aorta, medially by the left main bronchus, and laterally by mediastinal pleura.

"Aortopulmonary window" also refers to a congenital heart defect similar in some ways to persistent truncus arteriosus. Persistent truncus arteriosus involves a single valve; aortopulmonary window is a septal defect.