Venous outflow from the thoracic esophagus occurs. Clinical anatomy and physiology of the esophagus

The esophagus is a tube that runs from the throat to the stomach. The length of the esophagus depends on gender, age, head position (when flexed, it shortens, when extended, it lengthens), and averages 23-24 cm in women and 25-26 cm in men. It begins at the level of the VI cervical vertebra and ends at the level of the XI thoracic vertebra.

The esophagus consists of 4 sections:

Cervical.
Chest.
Diaphragmatic.
Abdominal.

Cervical region. It goes from the VI cervical to the II thoracic vertebra. The entrance to the esophagus depends on the position of the head: when flexed - at the level of the VII cervical vertebra, when extended - at the level of V-VI. This is important when identifying foreign bodies. The inner upper border of the esophagus is a labial fold, which is formed by a hypertrophied muscle (cricopharyngeus). When inhaling, this muscle contracts and closes the entrance to the esophagus, preventing aerophagia. The length of the cervical esophagus is 5-6 cm. In older people, it is shortened due to the prolapse of the larynx. In this section of the esophagus, 2/3 to 3/4 of all foreign bodies are retained. The outside of the esophagus in this section is covered with loose fiber, providing it with high mobility. This fiber passes into the upper mediastinum - if the esophagus is damaged, air enters the upper mediastinum. The esophagus in this section is adjacent to the spine at the back, to the trachea at the front, and the recurrent nerves and the thyroid gland are located on the sides.

Thoracic department. It goes from the II thoracic vertebra to the esophageal opening of the diaphragm (IX thoracic vertebra). This is the longest section: 16-18 cm. On the outside, it is covered with a thin layer of fiber and is fixed to the spinal fascia. At the level of the V thoracic vertebra, the left main bronchus or the tracheal bifurcation area is adjacent to the esophagus. Congenital and acquired tracheoesophageal fistulas often occur in this area. On the sides of the esophagus there are large paraesophageal and bifurcation lymph nodes. When they increase, depressions in the esophagus are visible.

Diaphragmatic section. Most important functionally. Its length is 1.5-2.0 cm. It is located at the level of the esophageal opening of the diaphragm. At this level, the adventitia of the esophagus is closely connected to the phrenic ligaments. Here, esophageal-diaphragmatic membranes are formed, which play a role in the formation of hiatal hernias

Abdominal section. The most variable: from 1 to 6 cm. It goes from the esophageal opening of the diaphragm to the XI thoracic vertebra. With age, this section lengthens. The outside is covered with loose fiber, which provides greater mobility in the longitudinal direction. The inner and lower border of the esophagus is the cardiac fold.

In addition to three anatomical narrowings, there are 4 physiological narrowings in the esophagus:

The mouth of the esophagus (VI cervical vertebra).
In the area of intersection with the aortic arch (III-IV thoracic vertebra) it is less pronounced. The frequent localization here of post-burn scars, as well as foreign bodies, is explained not only by the presence of an aortic narrowing of the esophagus, but also by the lateral bending of the esophagus above it.
In the area of the bifurcation of the trachea (V-VI thoracic vertebrae) and the intersection with the left main bronchus, where the latter is somewhat pressed into the esophagus.
In the area of the esophageal opening of the diaphragm (IX-X thoracic vertebra).

Distance from the maxillary incisors to the constrictions:

16-20 cm.
23 cm.
26 cm.
36-37 cm.

The distance from the incisors of the upper jaw to the cardia is 40 cm. The diameter of the esophagus in the cervical region is 1.8-2.0 cm, in the thoracic and abdominal regions 2.1-2.5 cm. The diameter of the esophagus increases when inhaling, and decreases when exhaling.

The wall of the esophagus consists of 4 layers:

Mucous membrane:
- epithelium,
- lamina propria of the mucous membrane,
- muscular plate of the mucous membrane.
Submucosal layer.
Muscle layer.
- circular muscle layer,
- longitudinal muscle layer.
Adventitia.

The epithelium is multilayered, flat, non-keratinizing. The mucous membrane is normally light pink in color with a delicate vascular pattern. In the area of the cardia, the stratified squamous epithelium of the esophagus passes into the columnar epithelium of the stomach, forming a dentate line. This is important when diagnosing esophagitis and cancer of the esophagus, in which the clarity of the line is lost; with cancer, the edges may be corroded. There may be up to 24 layers of epithelium. The upper and lower cardiac glands are located in the mucous membrane of the cervical and abdominal parts of the esophagus. There are 5 times more of them in the abdominal esophagus than in the stomach. They contain endocrine glands that secrete intestinal hormones: gastrin, secretin, somatostatin, vasopressin. Gastrin and secretin are involved in motility and trophism of the digestive tract. The glands are located in the lamina propria of the mucosa. The muscular plate of the mucous membrane consists of smooth muscle fibers.

The submucosal layer is formed by loose connective tissue, the severity of which determines the size of the folds.

The muscular layer consists of 2 types of fibers:

Cross-striped - located mainly in the upper 1/3 of the esophagus, in the middle 1/3 they become smooth.
Smooth muscle fibers - the lower 1/3 of the esophagus consists exclusively of them.

The muscular layer consists of two layers - the inner circular and outer longitudinal. The circular layer, located throughout its entire length, is thinner in the initial part of the esophagus; gradually thickening, it reaches its maximum size at the diaphragm. The layer of longitudinal muscle fibers thins in the area of the esophagus located behind the trachea, and in the final sections of the esophagus it thickens. In general, the muscular lining of the esophagus in the initial section, especially in the pharynx, is relatively thin; gradually it thickens towards the abdominal part. Both layers of muscle are separated by connective tissue in which the nerve plexuses lie.

Adventitia is loose connective tissue surrounding the outside of the esophagus. Well expressed above the diaphragm and at the junction of the esophagus and stomach.

Blood supply to the esophagus developed to a lesser extent than in the stomach, because there is no single esophageal artery. Different parts of the esophagus are supplied with blood differently.

Cervical region: inferior thyroid, pharyngeal and subclavian arteries.
Thoracic region: branches of the subclavian, inferior thyroid, bronchial, intercostal arteries, thoracic aorta.
Abdominal: from the left inferior phrenic and left gastric arteries.

Venous drainage carried out through veins corresponding to the arteries supplying the esophagus.

Cervical region: into the veins of the thyroid gland and into the innominate and superior vena cava.
Thoracic region: along the esophageal and intercostal branches into the azygos and semi-gypsy veins and, consequently, into the superior vena cava. From the lower third of the thoracic part of the esophagus, venous blood is sent through the branches of the left gastric vein and the upper branches of the splenic vein to the portal system. The left inferior phrenic vein drains part of the venous blood from this part of the esophagus into the inferior vena cava system.
Abdominal region: into the tributaries of the portal vein. In the abdominal region and in the area of the cardioesophageal junction there is a porto-caval anastomosis, which primarily expands in liver cirrhosis.

Lymphatic system formed by two groups of lymphatic vessels - the main network in the submucosal layer and the network in the muscular layer, which partially connects with the submucosal network. In the submucosal layer, lymphatic vessels run both in the direction of the nearest regional lymph nodes and longitudinally along the esophagus. In this case, lymphatic drainage in the longitudinal lymphatic vessels in the upper 2/3 of the esophagus occurs upward, and in the lower third of the esophagus - downward. This explains metastasis not only to the nearest, but also to distant lymph nodes. From the muscular network, lymphatic drainage goes to the nearest regional lymph nodes.

Innervation of the esophagus.

Parasympathetic:

nervus vagus,
recurrent nerve.

Sympathetic: nodes of the border, aortic, cardiac plexuses, ganglia in the subcardia.

The esophagus has its own innervation - the intramural nervous system, which is represented by Dopple cells and consists of three closely connected plexuses:

adventitial,
intermuscular,
submucosal.

They determine the internal autonomy of innervation and local innervation of the motor function of the esophagus. The esophagus is also regulated by the central nervous system.

Cardia. This is the junction of the esophagus with the stomach, acting as a functional sphincter and preventing the reflux of gastric contents into the esophagus. The cardiac sphincter is formed by thickening of the circular muscle layer of the esophagus. In the area of the cardia its thickness is 2-2.5 times greater than in the esophagus. In the area of the cardiac notch, the circular layers intersect and pass onto the stomach.

The closing function of the cardia depends on the physiological usefulness of the muscle fibers of the lower esophageal sphincter, the function of the right diaphragmatic leg and the muscles of the stomach, the acute angle between the left wall of the esophagus and the fundus of the stomach (the angle of His), the Laimer diaphragmatic-esophageal membrane, as well as the folds of the gastric mucosa (Gubarev's folds) ), which, under the influence of the gastric gas bubble, fit tightly to the right edge of the esophageal opening of the diaphragm.

(thoracic region)

Blood supply the thoracic part of the esophagus is carried out from many sources, is subject to individual variability and depends on the part of the organ. Thus, the upper part of the thoracic part is supplied with blood mainly by the esophageal branches of the lower thyroid artery, starting from the thyroid trunk (truncus thyrocervicalis), as well as by the branches of the subclavian arteries. The middle third of the thoracic part of the esophagus always receives blood from the bronchial branches of the thoracic aorta and relatively often from the I-II right intercostal arteries. The arteries for the lower third of the esophagus arise from the thoracic aorta, II-VI right intercostal arteries, but mainly from III, although in general intercostal arteries participate in the blood supply to the esophagus only in 1/3 of cases.

The main sources of blood supply to the esophagus are branches extending directly from the thoracic aorta. The largest and most permanent are the esophageal branches (rr. esophagei), the peculiarity of which is that they usually run along the esophagus for some distance, and then are divided into ascending and descending branches. The arteries of all parts of the esophagus anastomose well with each other. The most pronounced anastomoses are found in the lowest part of the organ. They form arterial plexuses, located mainly in the muscular layer and submucosa of the esophagus.

Venous drainage. The venous system of the esophagus is characterized by uneven development and differences in the structure of the venous plexuses and networks within the organ. The outflow of venous blood from the thoracic part of the esophagus is carried out into the system of the azygos and semi-gypsy veins, through anastomoses with the veins of the diaphragm - into the system of the inferior vena cava, and through the veins of the stomach - into the portal vein system. Due to the fact that the outflow of venous blood from the upper esophagus occurs into the superior vena cava system, the venous vessels of the esophagus are the connecting link between the three main venous systems (superior and inferior vena cava and portal veins).

Lymphatic drainage from the thoracic part of the esophagus occurs in various groups of lymph nodes. From the upper third of the esophagus, lymph is directed to the right and left paratracheal nodes, and some of the vessels carry it to the preventricular, lateral jugular and tracheobronchial nodes. Sometimes the lymphatic vessels of this section of the esophagus flow into the thoracic duct. From the middle third of the esophagus, lymph is directed primarily to the bifurcation nodes, then to the tracheobronchial nodes and then to the nodes located between the esophagus and the aorta. Less often, 1-2 lymphatic vessels from this section of the esophagus flow directly into the thoracic duct. From the lower part of the esophagus, the lymphatic drainage goes to the regional nodes of the stomach and mediastinal organs, in particular to the pericardial nodes, less often to the gastric and pancreatic nodes, which is of practical importance in the metastasis of malignant tumors of the esophagus.

Innervation the esophagus is carried out by the vagus nerves and sympathetic trunks. The upper third of the thoracic part of the esophagus is innervated by the branches of the recurrent laryngeal nerve (n. laryngeus recurrens dexter), as well as by esophageal branches extending directly from the vagus nerve. Due to the abundance of connections, these branches form a plexus on the anterior and posterior walls of the esophagus, which is vagosympathetic in nature.

The middle section of the esophagus in the thoracic part is innervated by branches of the vagus nerve, the number of which behind the roots of the lungs (at the site of passage of the vagus nerves) ranges from 2-5 to 10. Another significant part of the branches, heading to the middle third of the esophagus, arises from the pulmonary nerve plexuses. The esophageal nerves, just like in the upper section, form a large number of connections, especially on the anterior wall of the organ, which creates a kind of plexus.

In the lower part of the thoracic part, the esophagus is also innervated by the branches of the right and left vagus nerves. The left vagus nerve forms the anterolateral plexus, and the right one forms the posterolateral plexus, which, as they approach the diaphragm, form the anterior and posterior vagus trunks. In the same section, one can often find branches of the vagus nerves that arise from the esophageal plexus and go directly to the celiac plexus through the aortic opening of the diaphragm.

Sympathetic fibers originate from the 5-6 upper thoracic segments of the spinal cord, switch in the thoracic nodes of the sympathetic trunk and approach the esophagus in the form of visceral branches.

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Esophagus, esophagus, It is a narrow and long active tube inserted between the pharynx and the stomach and helps move food into the stomach. It begins at the level of the VI cervical vertebra, which corresponds to the lower edge of the cricoid cartilage of the larynx, and ends at the level of the XI thoracic vertebra.

Since the esophagus, starting in the neck, passes further into the chest cavity and, perforating the diaphragm, enters the abdominal cavity, its parts are distinguished: partes cervicalis, thoracica et abdominalis. The length of the esophagus is 23-25 cm. The total length of the path from the front teeth, including the oral cavity, pharynx and esophagus, is 40-42 cm (at this distance from the teeth, adding 3.5 cm, a gastric rubber probe must be advanced into the esophagus to take gastric juice for examination).

Topography of the esophagus. The cervical part of the esophagus is projected from the VI cervical to the II thoracic vertebra. The trachea lies in front of it, the recurrent nerves and common carotid arteries pass to the side.

The syntopy of the thoracic part of the esophagus is different at different levels: the upper third of the thoracic esophagus lies behind and to the left of the trachea, in front of it are the left recurrent nerve and the left a. carotis communis, behind - the spinal column, on the right - the mediastinal pleura. In the middle third, the aortic arch is adjacent to the esophagus in front and to the left at the level of the IV thoracic vertebra, slightly lower (V thoracic vertebra) - the bifurcation of the trachea and the left bronchus; behind the esophagus lies the thoracic duct; The descending part of the aorta is adjacent to the esophagus on the left and somewhat posteriorly, the right vagus nerve is on the right, and v. is adjacent to the right and posteriorly. azygos. In the lower third of the thoracic esophagus, behind and to the right of it lies the aorta, in front - the pericardium and the left vagus nerve, on the right - the right vagus nerve, which is shifted below to the posterior surface; v lies somewhat posteriorly. azygos; on the left - the left mediastinal pleura.

The abdominal part of the esophagus is covered with peritoneum in front and on the sides; the left lobe of the liver is adjacent to it in front and to the right, the upper pole of the spleen is to the left, and a group of lymph nodes is located at the junction of the esophagus and the stomach.

Structure. On a cross-section, the lumen of the esophagus appears as a transverse slit in the cervical part (due to pressure from the trachea), while in the thoracic part the lumen has a round or stellate shape.

The wall of the esophagus consists of the following layers: the innermost - the mucous membrane, tunica mucosa, the middle - tunica muscularis and the outer - connective tissue in nature - tunica adventitia.

Tunica mucosa contains mucous glands that facilitate the sliding of food during swallowing with their secretions. In addition to the mucous glands, small glands similar in structure to the cardiac glands of the stomach are also found in the lower and, less commonly, upper sections of the esophagus. When not stretched, the mucous membrane gathers into longitudinal folds. Longitudinal folding is a functional adaptation of the esophagus, facilitating the movement of fluids along the esophagus along the grooves between the folds and stretching the esophagus during the passage of dense lumps of food. This is facilitated by the loose tela submucosa, thanks to which the mucous membrane acquires greater mobility, and its folds easily appear and then smooth out. The layer of unstriated fibers of the mucous membrane itself, lamina muscularis mucosae, also participates in the formation of these folds. The submucosa contains lymphatic follicles.

Tunica muscularis, corresponding to the tubular shape of the esophagus, which, when performing its function of carrying food, must expand and contract, is located in two layers - the outer, longitudinal (dilating esophagus), and the internal, circular (constricting). In the upper third of the esophagus, both layers are composed of striated fibers; below they are gradually replaced by non-striated myocytes, so that the muscle layers of the lower half of the esophagus consist almost exclusively of involuntary muscles.

Tunica adventitia, surrounding the outside of the esophagus, consists of loose connective tissue through which the esophagus is connected to the surrounding organs. The looseness of this membrane allows the esophagus to change the size of its transverse diameter as food passes through.

Pars abdominalis of the esophagus covered with peritoneum.

X-ray examination of the digestive tube is carried out using the method of creating artificial contrasts, since without the use of contrast media it is not visible. For this, the subject is given a “contrast food” - a suspension of a substance with a high atomic mass, preferably insoluble barium sulfate. This contrast food blocks x-rays and produces a shadow on the film or screen that corresponds to the cavity of the organ filled with it. By observing the movement of such contrasting food masses using fluoroscopy or radiography, it is possible to study the x-ray picture of the entire digestive canal. When the stomach and intestines are completely or, as they say, “tightly” filled with a contrasting mass, the X-ray picture of these organs has the character of a silhouette or, as it were, a cast of them; with a small filling, the contrast mass is distributed between the folds of the mucous membrane and gives an image of its relief.

X-ray anatomy of the esophagus. The esophagus is examined in oblique positions - in the right nipple or left scapular. During an X-ray examination, the esophagus containing a contrasting mass has the appearance of an intense longitudinal shadow, clearly visible against the light background of the pulmonary field located between the heart and the spinal column. This shadow is like a silhouette of the esophagus. If the bulk of the contrast food passes into the stomach, and swallowed air remains in the esophagus, then in these cases one can see the contours of the walls of the esophagus, clearing at the site of its cavity and the relief of the longitudinal folds of the mucous membrane. Based on X-ray data, it can be noted that the esophagus of a living person differs from the esophagus of a corpse in a number of features due to the presence of intravital muscle tone in a living person. This primarily concerns the position of the esophagus. On the corpse it forms bends: in the cervical part the esophagus first runs along the midline, then slightly deviates from it to the left; at the level of the V thoracic vertebra it returns to the midline, and below it again deviates to the left and forward to the hiatus esophageus of the diaphragm. In a living person, the bends of the esophagus in the cervical and thoracic regions are less pronounced.

The lumen of the esophagus has a number of narrowings and expansions that are important in the diagnosis of pathological processes:

pharyngeal (at the beginning of the esophagus),
bronchial (at the level of tracheal bifurcation)
diaphragmatic (when the esophagus passes through the diaphragm).

These are anatomical narrowings that remain on the corpse. But there are two more narrowings - aortic (at the beginning of the aorta) and cardiac (at the transition of the esophagus to the stomach), which are expressed only in a living person. Above and below the diaphragmatic constriction there are two expansions. The inferior expansion can be considered as a kind of vestibule of the stomach. Fluoroscopy of the esophagus of a living person and serial photographs taken at intervals of 0.5-1 s allow one to study the act of swallowing and peristalsis of the esophagus.

Endoscopy of the esophagus. During esophagoscopy (i.e., when examining the esophagus of a sick person using a special device - an esophagoscope), the mucous membrane is smooth, velvety, and moist. Longitudinal folds are soft and plastic. Along them there are longitudinal vessels with branches.

The esophagus is fed from several sources, and the arteries feeding it form abundant anastomoses among themselves. Ah. esophageae to pars cervicalis of the esophagus come from a. thyroidea inferior. Pars thoracica receives several branches directly from the aorta thoracica, pars abdominalis feeds from the aa. phrenicae inferiores et gastrica sinistra. Venous outflow from the cervical part of the esophagus occurs in v. brachiocephalica, from the thoracic region - in vv. azygos et hemiazygos, from the abdominal - into the tributaries of the portal vein. From the cervical and upper third of the thoracic esophagus, lymphatic vessels go to the deep cervical nodes, pretracheal and paratracheal, tracheobronchial and posterior mediastinal nodes. From the middle third of the thoracic region, the ascending vessels reach the named nodes of the chest and neck, and the descending vessels (through the hiatus esophageus) reach the nodes of the abdominal cavity: gastric, pyloric and pancreaticoduodenal. Vessels coming from the rest of the esophagus (supradiaphragmatic and abdominal sections) flow into these nodes.

The esophagus is innervated from n. vagus et tr. sympathicus. Along the branches of tr. sympathicus conveys the feeling of pain; sympathetic innervation reduces esophageal peristalsis. Parasympathetic innervation enhances peristalsis and gland secretion.