An unusual course of the thoracic duct in relation to the vertebral vessels.

A variation in the course of the thoracic duct was found in the cervical portion of a male cadaver during routine dissection of the head and neck region for undergraduate students. The thoracic duct, while arching laterally above the clavicle, was coursing posterior to the vertebral vein but anterior to the vertebral artery; it normally passes anterior to both the vertebral vein and artery. To the best of our knowledge, this variation in relation to the vertebral vein has not yet been reported. In addition, after coursing posterior to the vertebral vein, the thoracic duct divided into two branches that drained separately, one at the angle between the internal jugular vein and subclavian vein, and the other into the subclavian vein. Knowledge of these variations is essential in order to prevent injury to the thoracic duct while performing surgeries at the root of the neck.