Lymphatic trunks and ducts

The lymph from each part of the body, passing through the lymph nodes, collects into the lymphatic ducts (ductus lymphatici) and lymphatic trunks (trunci lymphatici). Six such large lymphatic ducts and trunks are isolated in the human body. Three of them flow into the left venous angle (thoracic duct, left jugular and left subclavian trunks), three into the right venous angle (right lymph duct, right jugular and right subclavian trunks).

The largest and major lymphatic vessel is the thoracic duct. On it, the lymph flows from the lower extremities, the walls and organs of the pelvis, the abdominal cavity, the left half of the thoracic cavity. From the right upper limb, the lymph is directed to the right subclavian trunk, from the right side of the head and neck to the right jugular trunk, from the organs of the right half of the thoracic cavity to the right bronchoscopic trunk (truncus bronchomediastinalis dexter), flowing into the right lymph duct or independently into the right venous angle. From the left upper limb lymph flows through the left subclavian trunk, from the left side of the head and neck - through the left jugular trunk, I from the organs of the half of the thoracic cavity into the left bronchoscopic trunk (truncus bronchomediastinalis sinister) flowing into the thoracic duct.

The thoracic duct (ductus thoracicus) forms in the abdominal cavity, in the retroperitoneal tissue, at the level of the XII thoracic - II lumbar vertebrae as a result of the fusion of the right and left lumbar lymphatic trunks (trunci lumbales dexter et sinister). These trunks, in turn, are formed from the fusion of the endometrial lymphatic vessels, respectively, of the right and left lumbar lymph nodes. Approximately 25% of cases in the initial part of the thoracic duct, one or three lymphatic vessels emitting the mesenteric lymph nodes, which are called intestinal trunks (trunci intestinales). In the thoracic duct, the lymphatic vessels of the pre-invertebral, intercostal, and also the visceral (preorthalic) lymph nodes of the thoracic cavity emerge. The length of the thoracic duct is 30-40 cm.

The abdominal part (pars abdominalis) of the thoracic duct is its initial part. In 75% of cases, it has an extension - the cisterna of the thoracic duct (cisterna chyli, milky cistern) conical, ampulliform or fusiform. In 25% of cases, the beginning of the thoracic duct has the form of a network-like plexus formed by the enduring lymphatic vessels of the lumbar, celiac, mesenteric lymph nodes. The walls of the cistern of the thoracic duct are usually fused to the right foot of the diaphragm, which compresses the thoracic duct during respiratory movements and promotes the propulsion of the lymph. From the abdominal cavity of the thoracic (lymphatic) duct through the aortic opening of the diaphragm passes into the thoracic cavity, into the posterior mediastinum, which is located on the front surface of the spine, behind the esophagus, between the thoracic part of the aorta and the unpaired vein.

The thoracic part (pars thoracica) of the thoracic duct is the longest. It extends from the aortic opening of the diaphragm to the upper aperture of the thorax, where the duct passes into its upper cervical part (pars cervicalis). In the lower parts of the thoracic cavity behind the thoracic duct are the initial sections of the right posterior intercostal arteries covered by the intrathoracic fascia and the terminal sections of the same veins, in front - the esophagus. At the level of the VI-VII thoracic vertebrae, the thoracic duct begins to deviate to the left, at the level II-III of the thoracic vertebrae it extends from under the left edge of the esophagus, rises up behind the left subclavian and common carotid arteries and the vagus nerve. Here, in the upper mediastinum, to the left of the thoracic duct are the left mediastinal pleura, the esophagus to the right, and the spinal column behind. Lateral to the common carotid artery and behind the internal jugular vein at the level of V-VII cervical vertebrae, the cervical part of the thoracic duct curves and forms an arc. The arch of the thoracic duct (arcus ductus thoracici) rounds the dome of the pleura from above and somewhat behind, and then the mouth of the duct opens into the left venous corner or into the terminal section of the veins that form it. Approximately 50% of the cases of the thoracic duct before the entry into the vein have an extension. Also often the duct bifurcates, and in some cases in the form of 3-4 trunks falls into the venous corner or into the final sections of the veins that form it.

At the mouth of the thoracic duct there is a paired valve formed by its internal membrane, which prevents the blood from being thrown from the vein. Through the thoracic duct, there are 7-9 valves that prevent the back flow of lymph. The walls of the thoracic duct, in addition to the inner tunica interna and the outer tunica externa, contain a well-expressed midline (tunica media), capable of actively pushing lymph through the duct from its beginning to the mouth.

In about a third of cases, there is a doubling of the lower half of the thoracic duct: next to its main trunk is an additional thoracic duct. Sometimes local splittings (doubling) of the thoracic duct are found.

The right lymphatic duct (ductus lymphaticus dexter) is a vessel 10-12 mm long, into which the right subclavian, jugular and broncho-mediastinal trunks enter (in 18.8% of cases). Rarely there is a right lymphatic duct, which has one mouth. More often (in 80% of cases) it has 2-3 or more shoots. This duct runs into the corner formed by the fusion of the right internal jugular and subclavian veins, or into the terminal compartment of the internal jugular or subclavian (very rarely) vein. In the absence of the right lymphatic duct (81.2% of cases), the lymphatic vessels of the lymph nodes of the posterior mediastinum and tracheobronchial nodes (right bronchoscopic trunk), the right jugular and subclavian trunks emerge independently into the right venous angle, into the internal jugular or subclavian vein at the point of their fusion together.

The jugular trunk, right and left (truncus jugularis, dexter and sinister), is formed from the lymphatic vessels that carry out the lateral deep cervical (internal jugular) lymph nodes of the corresponding side. Each jugular trunk is represented by a single vessel or several vessels of small length. The right jugular trunk flows into the right venous angle, into the terminal section of the right internal jugular vein, or participates in the formation of the right lymphatic duct. The left jugular trunk flows directly into the left venous angle, into the internal jugular vein or, in most cases, into the cervical part of the thoracic duct.

The subclavical trunk, right and left (truncus subclavius, dexter et sinister), is formed from the lymphatic vessels that carry the axillary lymph nodes, mainly the apical lymph nodes, and in the form of one trunk or several small trunks is directed to the corresponding venous angle. The right subclavian trunk opens into the right venous angle or to the right subclavian vein, right lymph duct; the left subclavian trunk - in the left venous corner, the left subclavian vein and approximately in half of cases in the final part of the thoracic duct.

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