Which structure lies to the right of the thoracic duct in the posterior mediastinum?

Which structure lies to the right of the thoracic duct in the posterior mediastinum?

• A. Esophagus
• B. Aorta
• C. Superior vena cava
• D. Azygos vein

Answer: (D)

In the posterior mediastinum, the thoracic duct runs upward between the aorta on the left and the azygos vein on the right. It crosses from the right to the left around the T5–T6 level, ending on the left as it ascends to the neck. Therefore, the structure located to the right of the thoracic duct in this region is the azygos vein. The esophagus lies anterior to the duct, the aorta is on the left, and the superior vena cava is in the superior mediastinum, not in this posterior region.

In the posterior mediastinum, the thoracic duct runs upward between the aorta on the left and the azygos vein on the right. It crosses from the right to the left around the T5–T6 level, ending on the left as it ascends to the neck. Therefore, the structure located to the right of the thoracic duct in this region is the azygos vein. The esophagus lies anterior to the duct, the aorta is on the left, and the superior vena cava is in the superior mediastinum, not in this posterior region.