The azygos vein is a venous vessel that runs along the right side of the vertebral column, collecting blood from the posterior chest wall, esophagus, and mediastinal structures before arching over the right main bronchus to drain into the superior vena cava. While it is not routinely evaluated in standard ultrasound examinations, the azygos vein may be seen on echocardiography or during right upper quadrant abdominal imaging. Dilation of the azygos vein can be a sign of elevated right atrial pressure, superior vena cava obstruction, or portal hypertension with collateral circulation. Recognizing an enlarged azygos vein on imaging can alert clinicians to these important underlying conditions.
Sonography Term