The ligamentum arteriosum (Latin: arterial ligament) is a small ligament that is the remnant of the ductus arteriosus formed within three weeks after birth. At the superior end, the ligamentum attaches to the aorta—at the final part of the arch of aorta (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. This ligament also plays a role in major trauma; it fixes the aorta in place during rapid decelerations recoil, consequently potentially resulting in ruptured aorta.