Abnormal Origin of one Pulmonary Artery from the Ascending Aorta-Embryologic Considerations.

Anomalous origin of one of the pulmonary arteries from the aorta is unusual. The reported morbidity and mortality is mostly due to early onset vascular disease. Early surgical intervention has significantly improved outcomes. The diagnosis of this abnormality is challenging. The nomenclature used is inconsistent. Familiarity with this abnormality and consistent use of definitions and classifications is mandatory. An attempt is made to clarify misleading inconsistencies. An older ontogenetic theory is revisited.