Node of arch of azygos vein

At a glance

English

Node of arch of azygos vein

Latin (TA2)

Nodus arcus venae azygos

System

Lymphatic

Region

Whole body

Side

Single, on the midline

About the node of arch of azygos vein

The node of the arch of the azygos vein is a single named node, often called simply the azygos node. It lies in the right side of the superior mediastinum, in the angle between the right side of the lower trachea and the right main bronchus, where the azygos vein arches forwards over the root of the right lung to end in the superior vena cava. The node sits against the inner curve of this arch.

In this position it is closely related to the right side of the trachea, the superior vena cava in front, the right vagus nerve passing behind the root of the lung, and the mediastinal pleura on its lateral side. It is the lowest of the nodes running up the right side of the trachea, and it belongs with the right superior tracheobronchial and paratracheal nodes.

It receives lymph from the right lung, passed on from the bronchopulmonary nodes at the hilum and from the subcarinal nodes below. Its outflow goes up the right paratracheal chain to the right bronchomediastinal trunk.

Because most of the lymph of the right lung, and some of the left lower lobe, flows past this point, the node is often involved in lung cancer, sarcoidosis, tuberculosis and lymphoma. When large it can be seen on a chest radiograph as a bulge at the right tracheobronchial angle, where the azygos vein itself normally makes a small shadow. It is reached for biopsy at mediastinoscopy or by needle through the airway.

Course and drainage

Begins at

Afferent vessels from the right lung via the bronchopulmonary nodes, and from the subcarinal nodes.

Drains into

Efferent vessels pass up the right paratracheal nodes to the right bronchomediastinal trunk.

Drains

Filters lymph from the right lung at the right tracheobronchial angle. Often enlarged in lung cancer, sarcoidosis, tuberculosis and lymphoma, and sampled at mediastinoscopy.