Thoracic duct: characteristic

является основным ее сосудом. The thoracic duct of the lymphatic system is its main vessel. It can be formed in several ways. Let us consider in detail what the thoracic duct is.

Anatomy

Three shells are distinguished in the wall of the vessel: endothelial, muscular-fibrous and external. In the first there are 7-9 large semilunar valves. The muscular-fibrous membrane has a sphincter in the mouth. The adventitial (external) part grows to the pleura, the aorta and the spine. From the beginning in the duct, the abdominal, thoracic, cervical divisions are distinguished. The latter is represented in the form of an arc, and the first two are in the form of a long, distinct vessel that accompanies the descending aorta. The abdominal part passes through the aortic gap in the diaphragm into the thoracic cavity. проходит по левой боковой плоскости нижних позвонков сзади от нисходящей аорты. Here the thoracic duct passes along the left lateral plane of the lower vertebrae behind the descending aorta. Further, it deviates closer to the esophagus. In the region of the 2-3rd thoracic vertebra, the duct emerges from under the esophagus (its left margin). Then behind the common and subclavian arteries rises to the upper aperture. Then the vessel bends around the left and the left part of the pleura. в венозный угол либо ветви, формирующие его, - плечеголовную, подключичную, внутреннюю яремную. Here, forming an arc, the thoracic duct empties into the venous angle or the branches that form it - the brachiocephalic, subclavian, internal jugular. In this area, a semilunar valve and sphincter form in the vessel. в длину достигает 1-1,5 см, в редких случаях 3-4 см. The thoracic duct in length reaches 1-1.5 cm, in rare cases 3-4 cm.

Formation

образуется: The thoracic duct is formed:

1. The confluence of intestinal, lumbar or both, and the trunks of both sides.
2. Forming the branches of the milk tank. In this case, the thoracic duct looks like an ampullar, conical extension.
3. Merging only intestinal and lumbar trunks.

может образовываться и как сетевидное начало в форме петлистого крупного сплетения из чревных, поясничных, брыжеечных ветвей и выносящих сосудов. The thoracic duct can also form as a reticular beginning in the form of a loopy large plexus of celiac, lumbar, mesenteric branches and vascular vessels.

Specificity of the structure

Often, variability is manifested in topography and structure. In particular, it is noted:

1. Doubling of the thoracic department or formation of additional (one or several) ducts.
2. Different variants of interaction with pleura, aorta, deep cervical veins, esophagus.
3. Falling into the venous (jugular) corner, brachiocephalic, subclavian vein with several or one trunk.
4. Formation of the ampoule before the site of entry into the vessels.
5. Inflows can flow into the jugular corner or the components of its veins themselves.

Thoracic duct: right lymph duct

This element can also be formed in different ways:

1. The merging of subclavian, jugular, broncho-mediastinal trunks. . In this case, a short and wide thoracic duct is formed . This situation is noted in 18-20% of cases.
2. The right duct may be absent altogether. The trunks that form it open directly into the jugular corner or the vessels that make up it. This situation is observed in 80-82% of cases.
3. There is a separation of a very short, wide right duct before entering the corner for 2-3 or more stems. This form of discovery is called networked.

Trunks

There are three of them:

1. The jugular trunk. It is formed by the enduring cervical vessels. They come out of the deep and lateral nodes. This trunk accompanies the jugular inner vein to the corner. In this area, it empties into it or the vessels that form it, or takes part in the formation of the right duct.
2. Sub-key trunk. Its occurrence is determined by the fusion of vascular vessels from axillary nodes. The trunk passes near the subclavian vein, has a sphincter and valves. It opens either into the venous corner and the vessels that form it, or into the right duct.
3. Bronchiodiastinal trunk. It is formed by vascular vessels from bronchopulmonary, tracheal, mediastinal nodes. In this trunk there are valves. It opens into the right duct, or venous jugular corner, or into the vessels forming it. The latter include a brachiocephalic, subclavian, jugular vein.

The left vascular vessels open in the thoracic duct. From the upper tracheobronchial and mediastinal nodes they can pour into the venous angle. In lymphatic trunks, as in the duct, three shells are distinguished: adventitial, muscular-elastic and endothelial.

Pulmonary vesicles and nodes

Capillaries form two networks. One - superficial - is located in the visceral pleura. The second - deep - is formed near the pulmonary lobules and alveoli, around the branches of the vessels and bronchial tree. The surface network is represented by a combination of narrow and wide capillaries. It is single-layered. Capillaries are presented in the form of a plexus and spread over all surfaces in the visceral pleura. A deep network is three-dimensional. The lobular plexus acts as its main part. They send lymph in 2 directions. It enters the plexus of the pulmonary vessels and bronchi, and also into the pleural network. The bringing branches are formed at the level of the segments, they pass into the gate and share. They come out of the lungs together with the veins and open into the following visceral nodes:

1. Bronchopulmonary. They are divided into internal and extraorganic. The first are located in the share and segmental bronchi, the latter - in the root of the lung.
2. Tracheobronchial upper and lower. They lie over and under the tracheal bifurcation.

The vascular vessels flow into the anterior mediastinal and tracheobronchial nodes. Of these, they open into the bronchodiastinal trunk. In rare cases, the vessels may flow into the thoracic duct and the jugular venous angle.