Thoracic duct
Ductus thoracicus
Definition
The thoracic duct is the largest lymphatic vessel in the human body, responsible for transporting lymph from the majority of the body to the venous system.
The thoracic duct typically originates from the cisterna chyli, a dilated sac located at the level of the second lumbar vertebra (L2). Immediately aftere the cisterna chyli, the abdominal part of the thoracic duct ascends through the aortic hiatus of the diaphragm into the thoracic cavity.
In the thoracic cavity, the thoracic part of thoracic duct is usually situated between the azygos vein on the right and the aorta on the left, extending from the level of the diaphragm to the root of the neck. It travels posterior to the esophagus and anterior to the vertebral column, crossing from the right to the left side of the body at the level of the fifth thoracic vertebra (T5).
On the thoracic superior outlet, the cervical part of thoracic duct forms an arch and terminates at the left venous angle, where the left internal jugular vein and the left subclavian vein converge. However, there is significant anatomical variability in its termination. The most common termination site is the left venous angle, but it can also terminate at the internal jugular vein or the subclavian vein. The duct may end as a single vessel in most cases, but it can also divide into multiple branches before termination.
The afferent lymphatic vessels of the thoracic duct are:
For the cervical part of thoracic duct:
For the thoracic part of thoracic duct:
For the abdominal part of thoracic duct (through the cisterna chyli)
References
1.The Anatomy of the Thoracic Duct and Cisterna Chyli: A Meta-Analysis With Surgical Implications.Plutecki D, Bonczar M, Wilk J, et al.journal of Clinical Medicine. 2024;13(15):4285. doi:10.3390/jcm13154285.New Research
2.The Cisterna Chyli: A Systematic Review of Definition, Prevalence, and Anatomy.Moazzam S, O'Hagan LA, Clarke AR, et al.American Journal of Physiology. Heart and Circulatory Physiology. 2022;323(5):H1010-H1018. doi:10.1152/ajpheart.00375.2022.
3.Anatomical Study of the Thoracic Duct and Its Clinical Implications in Thoracic and Pediatric Surgery, a 70 Cases Cadaveric Study.Rabattu PY, Sole Cruz E, El Housseini N, et al.Surgical and Radiologic Anatomy : SRA. 2021;43(9):1481-1489. doi:10.1007/s00276-021-02764-z.
4.Review of Thoracic Duct Anatomical Variations and Clinical Implications.Phang K, Bowman M, Phillips A, Windsor J.Clinical Anatomy (New York, N.Y.). 2014;27(4):637-44. doi:10.1002/ca.22337.
5.Anatomical Variations in Distal Portion of the Thoracic Duct-a Systematic Review.Bellier A, Pardo Vargas JS, Cassiba J, et al.Clinical Anatomy (New York, N.Y.). 2020;33(1):99-107. doi:10.1002/ca.23476.
6.The Anatomy and Physiology of the Terminal Thoracic Duct and Ostial Valve in Health and Disease: Potential Implications for Intervention.Ratnayake CBB, Escott ABJ, Phillips ARJ, Windsor JA.Journal of Anatomy. 2018;233(1):1-14. doi:10.1111/joa.12811.
