[1] The thoracic duct usually begins from the upper aspect of the cisterna chyli, passing out of the abdomen through the aortic hiatus into first the posterior mediastinum and then the superior mediastinum, extending as high up as the root of the neck before descending to drain into the systemic (blood) circulation at the venous angle.

It also collects most of the lymph in the body other than from the right thorax, arm, head, and neck (which are drained by the right lymphatic duct).

The vessel usually commences at the level of the twelfth thoracic vertebra (T12) and extends to the root of the neck before descending to terminate at the venous angle.

[2] Abdomen From its origin at the cisterna chyli, the thoracic duct ascends anterior to and to the right of the vertebral column, situated in between the aorta, and the azygos vein.

[5] It passes posterior to the left common carotid artery, vagus nerve (CN X), and internal jugular vein.

[7] The thoracic duct becomes adaptively dilated in the presence of certain pathological conditions (congestive heart failure, portal hypertension, and malignancy).

When the thoracic duct is blocked or damaged a large amount of lymph can quickly accumulate in the pleural cavity, this situation is called chylothorax.