What is the thoracic duct and what is its main function?

The thoracic duct is the largest lymphatic vessel in the body. Its main function is to carry lymph (including chyle) from most of the body into the bloodstream, specifically draining into the venous angle at the junction of the left subclavian and internal jugular veins.

Where does the thoracic duct begin and end?

It begins at the cisterna chyli in the abdomen at the T12 vertebral level. It ends by terminating at the venous angle, which is the junction of the left subclavian and internal jugular veins in the neck.

What body regions does the thoracic duct drain?

The thoracic duct drains all body regions except the right side of the head and neck, chest wall, right lung, right side of the heart, and the right surface of the liver.

What is the course of the thoracic duct through the body?

Its course includes beginning at the cisterna chyli and entering the thorax through the aortic opening at T12, ascending in the posterior mediastinum to the right of midline until T5, then crossing to the left, continuing upward along the left esophagus border in the superior mediastinum, and arching laterally in the neck to terminate at the venous angle.

What are some key anatomical relations of the thoracic duct?

Key relations vary by location. In the posterior mediastinum, it lies anterior to the vertebral column and posterior to the esophagus. In the superior mediastinum, it is anterior to the vertebral column and posterior to the aortic arch. In the neck, it is anterior to the carotid sheath and posterior to the vertebral artery.

What are the tributaries that drain into the thoracic duct?

Tributaries include in the abdomen: lower six intercostal lymph nodes; in the thorax: ascending and descending lymph trunks, and posterior mediastinal lymph nodes; and in the neck: left jugular, subclavian, and bronchomediastinal lymph trunks.

What are common clinical conditions associated with the thoracic duct?

Common conditions include chylothorax: accumulation of chyle in the pleural cavity due to injury, such as during surgery; chylous fistula: postoperative leakage from cervical duct injury, often requiring ligation; and filarial obstruction: blockage from filariasis, potentially causing chylothorax or chyluria.

Thoracic Duct – Course, Tributaries & Drainage

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