Thoracic duct

Thoracic duct
Lymph: Thoracic duct
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The thoracic and right lymphatic ducts. (Thoracic duct is thin vertical white line at center.)
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Modes of origin of thoracic duct. a. Thoracic duct. a’. Cisterna chyli. b, c’ Efferent trunks from lateral aortic glands. d. An efferent vessel which pierces the left crus of the diaphragm. e. f. Lateral aortic glands. h. Retroaortic glands. i. Intestinal trunk. j. Descending branch from intercostal lymphatics.
Latin ductus thoracicus
Gray's subject #176 690
Source cisterna chyli
Drains to junction of the left subclavian vein and left internal jugular vein
MeSH Thoracic+Duct
Dorlands/Elsevier Thoracic duct

In human anatomy, the thoracic duct of the lymphatic system is the largest lymphatic vessel in the body. It is also known as the left lymphatic duct, alimentary duct, chyliferous duct, and Van Hoorne's canal.

It collects most of the lymph in the body (except that from the right arm and the right side of the chest, neck and head, and lower left lobe of the lung, which is collected by the right lymphatic duct) and drains into the systemic (blood) circulation at the left brachiocephalic vein between the left subclavian and left internal jugular veins.

Contents

Location

In adults, the thoracic duct is typically 38-45cm in length and an average diameter of about 5mm. It usually starts from the level of the second lumbar vertebra and extends to the root of the neck.

It originates in the abdomen from the confluence of the right and left lumbar trunk and the intestinal trunk, forming a significant pathway upward called the cisterna chyli.

It extends vertically in the chest and curves posteriorly to the left carotid artery and left internal jugular vein at the C7 vertebral level to empty into the junction of the left subclavian vein and left jugular vein, below the clavicle, near the shoulders.

It traverses the diaphragm at the aortic aperture and ascends the posterior mediastinum between the descending thoracic aorta (to its left) and the azygos vein (to its right).

Volume, mechanism, and direction of flow

In adults, the thoracic duct transports up to 4 L of lymph per day.

The lymph transport in the thoracic duct is mainly caused by the action of breathing, aided by the duct's smooth muscle and by internal valves which prevent the lymph from flowing back down again.

There are also two valves at the junction of the duct with the left subclavian vein, to prevent the flow of venous blood into the duct.

Clinical significance

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.

The first sign of a malignancy (especially an intraabdominal one) may be an enlarged Virchow's node, a lymph node in the left supraclavicular area, in the vicinity where the thoracic duct empties into the left subclavian vein.

Additional images

See also

References

External links


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Look at other dictionaries:

  • Thoracic duct — Thoracic Tho*rac ic, a. [Cf. F. thoracique.] (Anat.) Of or pertaining to the thorax, or chest. [1913 Webster] {Thoracic duct} (Anat.), the great trunk of the lymphatic vessels, situated on the ventral side of the vertebral column in the thorax… …   The Collaborative International Dictionary of English

  • thoracic duct — n. the main canal of the lymphatic system, passing along the front of the spinal column, collecting lymph and conveying it into the left subclavian vein …   English World dictionary

  • thoracic duct — The major efferent lymph duct into which lymph from most of the peripheral lymph nodes drains. Recirculating lymphocytes that have left the circulation in the lymph node return to the blood through the thoracic duct …   Dictionary of molecular biology

  • Thoracic duct — A vascular structure which recirculates lymph into the blood stream. It begins in the abdomen and tracks alongside the aorta and esophagus to eventually join with the left brachiocephalic vein. * * * thoracic duct n the main trunk of the system… …   Medical dictionary

  • thoracic duct —    This is the body s main lymph collecting vessel.    It starts in the little collecting bladder in the abdomen (the cisterna chyli), moves up the center of the body in front of the spinal chord, alongside the esophagus and aorta to the neck,… …   Herbal-medical glossary

  • thoracic duct — thorac′ic duct′ n. anat. the main trunk of the lymphatic system, passing along the spinal column in the thoracic cavity and conveying a large amount of lymph and chyle into the venous circulation • Etymology: 1720–30 …   From formal English to slang

  • thoracic duct — Anat. the main trunk of the lymphatic system, passing along the spinal column in the thoracic cavity, and conveying a large amount of lymph and chyle into the venous circulation. [1720 30] * * * …   Universalium

  • thoracic duct — /θəræsɪk ˈdʌkt/ (say thuhrasik dukt) noun the main trunk of the lymphatic system, passing along the spinal column in the thoracic cavity, and conveying a large amount of lymph and chyle into the venous circulation …  

  • thoracic duct — noun the major duct of the lymphatic system • Hypernyms: ↑lymph vessel, ↑lymphatic vessel • Part Holonyms: ↑lymphatic system, ↑systema lymphaticum …   Useful english dictionary

  • thoracic duct — noun Date: circa 1741 the main trunk of the system of lymphatic vessels that lies along the front of the spinal column and opens into the left subclavian vein …   New Collegiate Dictionary

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