Ligamentum arteriosum

A small, fibrous band that connects the aorta and the pulmonary artery.

Ligamentum arteriosum is a remnant of the ductus arteriosus, a fetal blood vessel that allows blood to bypass the lungs during gestation. After birth, the ductus arteriosus closes and transforms into this fibrous ligament, anchoring the aorta to the pulmonary artery. It plays a crucial role in the transition from fetal to postnatal circulation.

Terminologia Anatomica

ligamentum-arteriosum

System

Cardiovascular system

Function

In the context of fetal circulation, the ductus arteriosus allows the majority of blood to bypass the non-functioning fetal lungs, redirecting oxygenated blood from the placenta into systemic circulation. Once the baby takes its first breath, the need for this bypass is eliminated, and the ductus arteriosus closes, forming the ligamentum arteriosum. This transformation effectively helps establish normal postnatal circulation, where the lungs become the main site for oxygenation. Although the ligamentum arteriosum itself does not have a significant function after birth, its formation is a critical step in the adaptation of the circulatory system to life outside the womb.

Location

The ligamentum arteriosum is located in the mediastinum, a space within the thoracic cavity. Specifically, it stretches between the inferior surface of the aortic arch and the pulmonary artery. This positioning places it posterior to the ascending aorta and anterior to the left main bronchus, making it an anatomical landmark during surgical procedures in the region.

Did You Know?

The ligamentum arteriosum is generally around 1-2 centimeters in length.
In some individuals, the ligamentum arteriosum may remain patent or reopen, which can lead to congenital heart conditions.
Understanding the anatomy of the ligamentum arteriosum is crucial for cardiothoracic surgeons performing procedures near the aorta and pulmonary arteries.