The ligamentum arteriosum (arterial ligament), also known as Botallo's ligament, Harvey's ligament, and Botallo's duct, is a small ligament attaching the aorta to the pulmonary artery. It serves no function in adults but is the remnant of the ductus arteriosus formed within three weeks after birth.
Structure
At the superior end, the ligamentum attaches to the aorta—at the final part of the aortic arch (the isthmus of aorta) or the first part of the descending aorta. On the other, inferior end, the ligamentum is attached to the top of the left pulmonary artery.
The ligamentum arteriosum is closely related to the left recurrent laryngeal nerve, a branch of the left vagus nerve. After splitting from the left vagus nerve, the left recurrent laryngeal loops around the aortic arch behind the ligamentum arteriosum, after which it ascends to the larynx.