Ligamentum arteriosum

The ligamentum arteriosum is the fibrous remnant of the fetal ductus arteriosus, a vessel that connects the left pulmonary artery to the aortic arch during fetal development. After birth, the ductus arteriosus typically undergoes closure and fibrosis, transforming into this ligamentous structure. In adults, the ligamentum arteriosum is located in the middle mediastinum, attaching the superior aspect of the left pulmonary artery to the inferior aspect of the aortic arch, near the isthmus.