The importance of the portal vein of the liver. All about the portal vein and blood flow in the liver

The outflow of venous blood from the unpaired abdominal organs does not occur directly into the general circulatory system, but through the portal vein into the liver.

Portal vein,v. portae collects blood from unpaired abdominal organs. It is formed behind the head of the pancreas by the fusion of three veins: the inferior mesenteric vein, v. mesenterica inferior, superior mesenteric vein, v. mesenterica superior, and splenic vein, v. lienalis.

Inferior mesenteric vein,v. mesenterica inferior, collects blood from the walls of the upper part of the rectum, sigmoid colon and descending colon and with its branches corresponds to all the branches of the inferior mesenteric artery.

Superior mesenteric veinv. mesenterica superior collects blood from the small intestine and its mesentery, the appendix and cecum, the ascending and transverse colon and from the mesenteric lymph nodes of these areas. The trunk of the superior mesenteric vein is located to the right of the artery of the same name and accompanies all the branches of the artery with its branches.

Splenic vein,v.lienalis, collects blood from the spleen, stomach, pancreas and greater omentum. It is formed in the area of ​​the gate of the spleen from numerous vv. lienales emerging from the substance of the spleen. From the gate of the spleen, the splenic vein is directed to the right along the upper edge of the pancreas, located below the artery of the same name.

The portal vein from the place of its formation goes to the hepato-duodenal ligament, between the leaves of which it reaches the gate of the liver. In the thickness of the specified ligament, the portal vein is located together with the common bile duct and the common hepatic artery in such a way that the duct occupies an extreme position on the right, to the left of it is the common hepatic artery, and deeper and between them is the portal vein. At the gate of the liver v. The portae is divided into two branches: the left branch, ramus sinister, and the right branch, ramus dexter, respectively, to the right and left lobes of the liver. Three veins: inferior mesenteric vein, v. mesenterica inferior, superior mesenteric vein, v. mesenterica superior, and splenic vein, v. lienalis, from which v is formed. portae are called portal vein roots.

In addition to these veins, which form the portal vein, the following veins flow directly into its trunk: left and right gastric veins, vv. gastricae sinistra et dextra, pancreatic veins, vv. pancreaticae... In addition, the portal vein is connected to the veins of the anterior abdominal wall through umbilical veins, vv. paraumbilicales.

Venous anastomoses

The venous bed is many times larger than the arterial bed and is more diverse in structure and function. In the venous system, in addition to the main, deep veins and their tributaries, the superficial or saphenous veins, as well as the widely developed venous plexuses, which constitute a powerful roundabout outflow channel, serve as additional pathways for the outflow of blood, in addition to the main, deep veins and their tributaries. Some of them play the role of special venous depots. The tributaries of the venous trunks form a variety of networks and plexuses inside and outside organs. These connections, or anastomoses (from the Greek. Anastomoo - I supply with the mouth, I inform, I connect) contribute to the movement of blood in different directions, moving it from one area to another.

Venous anastomoses play an extremely important role in the distribution of blood in areas of the body and are of particular importance in pathology with violations of blood flow in the main venous lines or their tributaries, providing collateral (roundabout) blood circulation, that is, the movement of blood along the paths formed by the lateral branches of the main vessels.

Venous blood from the whole body is collected in two main venous collectors - the superior and inferior vena cava, which carry it to the right atrium. In the abdominal cavity, in addition to the inferior vena cava system, there is also a portal vein with its tributaries that collect blood from the stomach, intestines, pancreas, gallbladder and spleen.

Anastomoses connecting the tributaries of any large vein to each other, located inside the basin of the branching of a given vessel, are intrasystem Unlike intersystem anastomoses connecting the tributaries of the veins of various systems. Distinguish between cava-caval and port-caval intersystem anastomoses.

Kava-caval anastomoses

Cava-caval anastomoses provide a roundabout blood flow to the right atrium in cases of thrombosis, ligation, compression of the vena cava and their large tributaries and are formed by the veins of the walls of the chest and abdomen, as well as by the venous plexuses of the spine.

Anastomosis of the posterior wall of the chest and abdomen (fig. 50). Four vv. lumbales flowing into v. cava inferior, are connected on each side by longitudinal anastomoses with each other, making up a vertically extending ascending lumbar vein - v. lumbalis ascendens, which in the cranial direction immediately continues to the right in v. azygos, and on the left - in v. hemiazygos from the superior vena cava system. Thus, there is a double pathway for the outflow of venous blood from the retroperitoneal space: first, along v. cava inferior, secondly, along the v. azygos and v. haemiazygos to v. cava superior. Strong development v. azygos is observed when v. cava inferior, for example, during a large pregnancy - multiple pregnancies, when venous blood from the lower half of the body is forced to look for new outflow pathways.

Rice. 50. Scheme of the anastomosis of the posterior wall of the chest and abdomen. 1 - vv. brachiocephalecae; 2 - v. cava superior; 3 - v. hemiazygos; 4 - v. lumbalis ascendens; 5 - v. lumbalis; 6 - v. cava inferior; 7 - v. azygos

Anastomoses formed by the venous plexuses of the spine (Fig. 51).

There are external and internal vertebral plexuses. The internal vertebral plexus is represented by the anterior and posterior. Only the anterior of the vertebral plexuses is of practical importance; the posterior is represented by thin venous vessels, damage to which during the operation is not accompanied by noticeable bleeding. With vertebral plexuses through vv. intervertebrales are reported: in the cervical spine - vertebral veins, vv. vertebrales, as well as the veins of the base of the skull and venous sinuses of the dura mater; in the thoracic region - intercostal veins, vv. intercostales posteriores; in the lumbar region - lumbar veins, vv. lumbales; in the sacral region - the veins of the walls and tissue of the small pelvis.

Rice. 51. Scheme of the anastomoses formed by the venous plexuses of the spine. 1 – v. intervertebralis; 2 – plexus vertebrales; 3 – v. vertebralis; 4 - v. brachiocephalica sinistra; 5 – v. hemiazygos accessoria; 6 – v. hemiazygos; 7 - v. lumbalis; 8 – v. cava inferior; 9 – v. iliaca communis sinistra; 10 – v. azygos

Thus, the venous plexuses of the spine take in blood not only from the spinal cord and the spinal column itself, but also abundantly communicate with the veins of various areas of the body. The blood flow in the venous plexuses of the spine can be carried out in any direction due to the absence of valves. The plexuses, as it were, unite the tributaries of the vena cava, being a connecting link between them. They represent important roundabout paths of blood flow both from the superior vena cava to the inferior and vice versa. Therefore, their role in the roundabout venous circulation is very significant.

Anastomoses of the anterior and lateral walls of the chest and abdomen (fig. 52)

Due to the anastomosis of the veins from the system of the superior and inferior vena cava on the anterior abdominal wall, venous plexuses are formed, communicating with each other: superficial (subcutaneous) and deep (in the sheath of the rectus abdominis muscle).

Rice. 52. Scheme of anastomoses of the anterior and lateral walls of the chest and abdomen: 1 - v. jugularis interna; 2 - v. subclavia; 3 – v. thoracica lateralis; 4 - v. thoracoepigastrica; lis; 8 - v. femoralis; 9 - v. iliaca interna; 10 – v. iliaca communis; 11 – v. cava inferior; 12 - v. portae; 13 – v. paraumbilicalis; 14 - v. thoracica interna; 15 - v. cava superior

Blood from the deep plexus is diverted, on the one hand, along the superior epigastric veins, vv. epigastricae superiores, tributaries vv. thoracicae internae, and those, in turn, flow into the brachiocephalic veins; and on the other hand, along the lower epigastric veins, vv. epigastricae inferiores, tributaries vv. iliacae externae from the inferior vena cava system. The vv is formed from the subcutaneous plexus. thoracoepigastricae flowing into vv. thoracicae laterales. and those in vv. axillares, and also - vv. epigastricae superficiales - tributaries vv. femorales from the inferior vena cava system.

Anastomoses, which also refer to cava-caval ones, have a certain functional significance, for example, between the veins of the heart and lungs, heart and diaphragm, the veins of the renal capsule with the veins of the adrenal gland and testicular (ovarian) veins, etc.

Table 5

Basic kava- caval anastomoses

Localization anastomosis	Anastomosing veins
	Top system vena cava	Lower system vena cava
The posterior wall of the chest and abdominal cavities	v. azygos, v. hemiazygos	v. lumbalis ascendens
Venous plexus spine	vv. intercostales posteriores (v. azygos, v. hemiazygos)
Front and side walls of the chest and abdomen	1) v. epigastrica superior (v. thoracica interna) 2) v. thoracoepigastrica	1) v. epigastrica inferior (v. iliaca externa) 2) v. epigastrica superficialis

Porto-caval anastomoses

The portal vein system contains more than half of the total amount of blood in the body and is an important part of the circulatory system. Any kind of blood flow disturbance in the v system. portae lead to increased blood pressure and the development of portal hypertension syndrome. It can be caused by congenital narrowing, thrombosis or compression of the portal vein (subhepatic block), liver disease (cirrhosis, tumors), leading to compression of the intrahepatic veins (intrahepatic block) and impaired venous outflow through the hepatic veins (suprahepatic block). Acute portal vein obstruction is usually fatal. Gradual disturbance of blood circulation in its system causes the development of collateral circulation, due to intrasystem, port-portal anastomoses (between the tributaries of the portal vein itself), which are carried out mainly due to the veins of the gallbladder, gastric veins, accessory portal veins and intersystem, porto-caval anastomoses.

Porto-caval anastomoses are normally poorly developed. They expand significantly in case of violations of the outflow of blood through the portal vein. In this case, the port-caval anastomoses provide a "discharge" of blood bypassing the liver, which has not undergone detoxification in it, from the portal vein system into the superior and inferior vena cava system. Reverse flow is of little practical importance.

The value of porto-caval anastomoses is only relative, rather mechanical than biological. Thanks to them, the pressure in the portal vein system decreases, and the resistance to the work of the heart decreases.

There are 4 main groups of anastomoses between the tributaries of the portal and vena cava, which form the pathways of the collateral blood flow.

Porto-cava-caval anastomosis in the anterior abdominal wall (fig. 53)

In the area of ​​the umbilical ring there is a venous plexus in the sheath of the rectus abdominis muscle, which communicates with the subcutaneous umbilical plexus. From these plexuses, veins are formed from the system of the superior and inferior vena cava (see cava-caval anastomosis), as well as vv. paraumbilicales, which, located in the anterior edge of the falciform ligament of the liver, next to the overgrown umbilical vein (round ligament of the liver), communicate with the left branch of the portal vein or with its trunk itself at the gate of the liver.

Rice. 53. Diagram of the port-caval anastomosis in the anterior abdominal wall. 1 - v. jugularis interna; 2 - v. subclavia; 3 – v. thoracica lateralis; 4 - v. thoracoepigastrica; 5 - v. epigastrica superior; 6 - v. epigastrica superficialis; 7 - v. epigastrica inferior; 8 - v. femoralis; 9 - v. iliaca interna; 10 – v. iliaca communis; 11 – v. cava inferior; 12 - v. portae; 13 – v. paraumbilicalis; 14 - v. thoracica interna; 15 - v. cava superior

The umbilical vein, which often retains its lumen, is also involved in the formation of this anastomosis. Complete obliteration is observed only in its distal part within 2-4 cm from the navel.

With stagnation of blood in the portal vein system, the paraumbilical veins sometimes expand to the diameter of the femoral vein, as well as the veins of the anterior abdominal wall in the circumference of the navel, called "caput Medusae", which is observed in cirrhosis of the liver and indicates a great danger to the patient's life.

Anastomosis in the wall of the cardiac part of the stomach and the abdominal part of the esophagus ( rice . 54)

From the venous plexus of the thoracic esophagus vv. esophageae fall into v. azygos and v. hemiazygos (superior vena cava system), from the abdominal part - in v. gastrica sinistra, which is an inflow of the portal vein.

With portal hypertension, the venous plexus in the lower esophagus expands extremely, acquiring the character of nodes that are easily injured during the passage of food and respiratory excursions of the diaphragm. Expansion of the veins of the esophagus sharply disrupts the function of the cardiac sphincter, as a result of which there is a gaping of the cardia and the throwing of acidic gastric contents into the esophagus. The latter causes ulceration of the nodes, which can lead to fatal bleeding.

Anastomosis in the wall of the ascending and descending colon (Retzius system) (Fig. 55).

From the venous plexus of the ascending and descending colon are formed, respectively, v. colica dextra flowing into v. mesenterica superior and v. colica sinistra - in v. mesenterica inferior, which are the roots of the portal vein. The posterior wall of these parts of the colon is not covered by the peritoneum and is adjacent to the muscles of the posterior abdominal wall, where vv are located. lumbales - tributaries of the inferior vena cava, as a result of which part of the blood from the venous plexus of the ascending and descending colon can flow into the system of the inferior vena cava.

With portal hypertension, varicose expansion of the venous plexus of these parts of the colon is observed, which can cause intestinal bleeding.

Anastomosis in the rectal wall (Fig. 56)

The internal (submucous), external (subfascial) and subcutaneous venous plexuses of the rectum, which are directly connected to each other, are distinguished. Blood from the internal plexus flows into the external one, and from the latter v are formed. rectalis superior - supply v. mesenterica inferior - one of the roots of the portal vein and v. rectalis media, which flows into v. iliaca interna - from the inferior vena cava system. From the subcutaneous venous plexus in the perineal region, v is formed. rectalis inferior, which flows into v. pudenda interna - supply v. iliaca interna.

Rice. 56. Scheme of anastomosis in the rectal wall: 1 - v. portae; 2 - v. cava inferior; 3 - v. mesenterica interior; 4 - v. iliaca communis; 5 - v. pudenda interna; 6 - v. rectalis inferior; 7 - v. rectalis media; 8 - v. iliaca interna; 9 - v. rectalis superior

The main drainage vessel of the rectum is the superior rectal vein, which drains blood from the mucous membrane and submucosa of the anal canal and all layers of the pelvic intestine. No valves were found in the superior rectal vein. The lower and middle rectal veins have a more regional significance in the outflow of blood from the organ, they are extremely variable and can sometimes be absent on one or both sides. Stagnation of blood in the inferior vena cava or portal vein system can contribute to the development of varicose veins of the rectum and the formation of hemorrhoids, which can be thrombosed and inflamed, and during the act of defecation, damage to the nodes leads to hemorrhoidal bleeding.

In addition to the mentioned port-caval anastomoses, there are also additional ones located in the retroperitoneal space: between the veins of the colon descendens and v. renalis sinistra; between tributaries v. mesenterica superior and v. testicularis dextra; between v. lienalis, v. renalis sinistra and roots v. azygos or v. hemiazygos.

Table 6

Major port-caval anastomoses

Localization anastomosis	Anastomosing veins
	System portal vein	System superior vena cava	System inferior vena cava
Anterior abdominal wall	vv. paraumbilicales	v. epigastrica superior (v. thoracica interna) v. thoracoepigastrica	v. epigastrica inferior (v. iliaca externa) v. epigastrica superficialis
The wall of the abdominal esophagus and the cardiac part of the stomach	vv. esophageales (v. gastrica sinistra)	vv. esophageales
Wall colon ascendens et descendens	v. colica dextra (v. mesenterica superior) v. colica sinistra (v.mesenterica inferior)
Rectal wall	v. rectalis superior (v.mesenterica inferior)		v. rectalis media (v. iliaca interna) v. rectalis inferior (v. pudenda interna)

Fetal circulation

Fetal circulation is otherwise called placental circulation (Fig. 57): in the placenta, there is an exchange of substances between the blood of the fetus and the mother's blood (while the blood of the mother and the fetus does not mix). V placenta,placenta, the umbilical vein begins with its roots, v. umbilicalis, through which arterial blood oxidized in the placenta is directed to the fetus. Following as part of the umbilical cord (umbilical cord), funiculus umbilicalis, to the fetus, the umbilical vein enters through the umbilical ring, anulus umbilicalis, into the abdominal cavity, goes to the liver, where part of the blood through the ductus venosus (ductusvenosus) is discharged into the inferior vena cava, v. cava inferior, where it mixes with venous blood, and another part of the blood passes through the liver and through the hepatic veins also flows into the inferior vena cava. Blood through the inferior vena cava enters the right atrium, where its main mass, through the valve of the inferior vena cava, valvula venae cavae inferioris, passes through the foramen ovale, foramen ovale, of the interatrial septum into the left atrium.

Rice. 57. Fetal circulation:

1 - ductus arteriosus (ductus arteriosus); 2 - umbilical arteries (aa. umbilicales); 3 - portal vein (v. portae); 4 - umbilical vein (v. umbilicalis); 5 - placenta (placenta); 6 - venous duct (ductus venosus); 7 - hepatic veins (vv. hepaticae); 8 - oval hole (foramen ovale)

From here it follows into the left ventricle, and then into the aorta, along the branches of which it is directed primarily to the heart, neck, head and upper limbs. In the right atrium, except for the inferior vena cava, v. cava inferior, brings venous blood to the superior vena cava, v. cava superior, and the coronary sinus of the heart, sinus coronarius cordis. Venous blood entering the right atrium from the last two vessels is sent along with a small amount of mixed blood from the inferior vena cava to the right ventricle, and from there to the pulmonary trunk, truncus pulmonalis. The ductus arteriosus (ductus arteriosus) flows into the aortic arch, below the place where the left subclavian artery leaves it, which connects the aorta with the pulmonary trunk and through which blood from the latter flows into the aorta. From the pulmonary trunk, blood enters the lungs through the pulmonary arteries, and its excess through the ductus arteriosus, ductus arteriosus, is sent to the descending aorta.

Thus, below the confluence of the ductus arteriosus, the aorta contains mixed blood from the left ventricle, rich in arterial blood, and blood from the ductus arteriosus, with a high content of venous blood. Along the branches of the thoracic and abdominal aorta, this mixed blood is directed to the walls and organs of the thoracic and abdominal cavities, the pelvis and to the lower extremities. Part of the indicated blood follows two - right and left - umbilical arteries, aa. umbilicales dextra et sinistra, which, located on both sides of the bladder, leave the abdominal cavity through the umbilical ring and, as part of the umbilical cord, funiculus umbilicalis, reach the placenta.

In the placenta, the fetal blood receives nutrients, gives off carbon dioxide and, enriched with oxygen, is again directed through the umbilical vein to the fetus. After birth, when the pulmonary circulation begins to function and the umbilical cord is tied, there is a gradual desolation of the umbilical vein, venous and arterial ducts and distal umbilical arteries; all these formations are obliterated and form ligaments.

Umbilical vein, v. umbilicalis, forms a round ligament of the liver, lig. teres hepatis; the venous duct, ductus venosus - the venous ligament, lig. venosum; arterial duct, ductus arteriosus - arterial ligament, lig. arteriosum, and from both umbilical arteries, aa. umbilicales, cords are formed, medial umbilical ligaments, ligg. umbilicalia medialia, which are located on the inner surface of the anterior abdominal wall. An oval hole, foramen ovale, also grows, which turns into an oval fossa, fossa ovalis, and the valve of the inferior vena cava, valvula v. cavae inferioris, which has lost its functional significance after birth, forms a small fold stretched from the mouth of the inferior vena cava towards the oval fossa.

The portal vein collects blood from all unpaired abdominal organs, with the exception of the liver: from the entire gastrointestinal tract, where absorption of nutrients occurs, which enter the liver through the portal vein to detoxify and deposit glycogen; from the pancreas, where insulin comes from, which regulates sugar metabolism; from the spleen, from where the breakdown products of blood elements come, which are used in the liver to produce bile. The constructive connection of the portal vein with the gastrointestinal tract and its large glands (liver and pancreas) is due, in addition to the functional connection, and the generality of their development (genetic connection).

V. portae, portal vein, represents a thick venous trunk located in the lig. hepatoduodenale together with the hepatic artery and ductus choledochus. Composed v. portae behind the head of the pancreas from the splenic vein and two mesenteric - superior and inferior. Heading to the gate of the liver in the mentioned ligament of the peritoneum, on the way it takes vv. gastricae sinistra et dextra and v. prepylorica and at the gate of the liver is divided into two branches, which go into the liver parenchyma. In the parenchyma of the liver, these branches split into many small branches, which entwine the hepatic lobules (vv. Interlobulares); numerous capillaries penetrate into the very lobules and eventually form into vv. centrales(see "Liver"), which are collected in the hepatic veins that flow into the inferior vena cava. Thus, the portal vein system, unlike other veins, is inserted between two capillary networks: the first capillary network gives rise to the venous trunks, from which the portal vein is composed, and the second is located in the liver substance, where the portal vein is divided into its terminal branches.

V. lienalis, splenic vein, carries blood from the spleen, stomach (via v. gastroepiploica sinistra and vv. gastricae breves) and from the pancreas, along the upper edge of which behind and below the artery of the same name, it goes to v. portae.

Vv. mesentericae superior et inferior, superior and inferior mesenteric veins, correspond to the arteries of the same name. V. mesenterica superior on its way takes into itself the venous branches from the small intestine (vv.intestinales), the cecum, the ascending colon and transverse colon (v. colica dextra and v. colica media), and, passing behind the head of the pancreas, connects to the inferior mesenteric vein. V. mesenterica inferior starts from venous plexus of the rectum, plexus venosus rectalis... Heading up from here, on the way it receives tributaries from the sigmoid colon. (vv. sigmoideae), from the descending colon (v. colica sinistra) and from the left half of the transverse colon. Behind the head of the pancreas, it, having previously connected with the splenic vein or independently, merges with the superior mesenteric vein.

Portal vein [of the liver],v. portae (hepatis), occupies a special place among the veins that collect blood from the internal organs (Fig. 73). It is not only the largest visceral vein (its length is 5-6 cm, its diameter is 11 -18 mm), but it is also the bearing venous link of the so-called portal system of the liver. The portal vein of the liver is located in the thickness of the hepato-duodenal ligament behind the hepatic artery and common bile duct along with nerves, lymph nodes and blood vessels. Formed from the veins of the unpaired abdominal organs: stomach, small and large intestine, except for the anal canal, spleen, pancreas. From these organs, venous blood flows through the portal vein to the liver, and from it through the hepatic veins to the inferior vena cava. The main tributaries of the portal vein are the superior mesenteric and splenic veins, as well as the inferior mesenteric vein, which merge with each other behind the head of the pancreas. Entering the gate of the liver, the portal vein is divided into a larger right branch, r.dexter, and left branch, r.sinister. Each of the branches, in turn, splits first into segmental, and then into branches of ever smaller diameter, which pass into the interlobular veins. Inside the lobules, they give off wide capillaries - the so-called sinusoidal vessels that flow into the central vein (Fig. 74). Sublobular veins emerging from each lobule, merging, form 3-4 hepatic veins,vv. hepdticae. Thus, the blood flowing into the inferior vena cava through the hepatic veins passes on its way through two capillary networks: located in the wall of the digestive tract, where the inflows of the portal vein originate, and formed in the liver parenchyma from the capillaries of its lobules.

Before entering the gate of the liver (in the thickness of the hepato-duodenal ligament), they flow into the portal vein biliary vein,v. cystica (from the gallbladder) right and left gastric veins,vv. gastricae dextra et sinistra, and pre-gate vein,v. prepylorica, delivering blood from the corresponding parts of the stomach. The left gastric vein anastomoses with the esophageal veins - tributaries of the azygos vein from the superior vena cava system. In the thickness of the round ligament, the liver follows to the liver umbilical veins,vv. paraumbilicales. They begin in the navel, where they anastomose with the superior epigastric veins - tributaries of the internal thoracic veins (from the superior vena cava system) and with the superficial and inferior epigastric veins (vv. epigdstricae superficiales et inferior) - tributaries of the femoral and external iliac veins from the inferior vena cava system (Fig. 75).

Portal vein tributaries:

1. Superior mesenteric vein,v. mesenterica superior, goes at the root of the mesentery of the small intestine to the right of the artery of the same name. Its tributaries are veins of the jejunum and ileum,vv. jejundtes et ileales; pancreatic veins,vv. pancreaticae; pancreatoduodenal veins,vv. pancreaticoduodendles; nod- iliocolic vein,v. Ueocollca; right gastroepiploic vein,v. gastroepiploica [ gastroomentdlis ] dextra; right and middle colic veins,vv. colicae media et dextra; vein of the appendix,v. appendiculdris. The listed veins bring blood to the superior mesenteric vein from the walls of the jejunum and ileum and the appendix, the ascending colon and transverse colon, partly from the stomach, duodenum and pancreas, and the greater omentum.

2Splenic veinv. liendlis [ splenca], located along the upper edge of the pancreas below the splenic artery, runs from left to right, crossing the aorta in front, and behind the head of the pancreas merges with the superior mesenteric vein. Its tributaries are pancreatic veins,vv. pancreaticae; short gastric veins,vv. gdstricae breves, and left gastroepiploic vein,v. gastro­ epiploica [ gastroomentdlis] sinistra. The latter anastomoses along the greater curvature of the stomach with the right vein of the same name. The splenic vein collects blood from the spleen, part of the stomach, pancreas, and greater omentum.

3Inferior mesenteric veinv. mesenterica inferior, formed by merger superior rectal vein,v. rec- tdlis superior, left colic vein,v. colica sinistra, and sigmoid veins,vv. sigmoideae. Located next to the left colic artery, the inferior mesenteric vein goes up, passes under the pancreas, and flows into the splenic vein (sometimes into the superior mesenteric vein). This vein collects blood from the walls of the upper rectum, the sigmoid colon, and the descending colon.

The liver is a vital gland of human external secretion. Its main functions include neutralizing toxins and removing them from the body. In case of liver damage, this function is not performed and harmful substances enter the bloodstream. With the blood stream, they flow through all organs and tissues, which can lead to serious consequences.

Since there are no nerve endings in the liver, a person may not even suspect that there is any disease in the body for a long time. In this case, the patient goes to the doctor too late, and then the treatment no longer makes sense. Therefore, you need to carefully monitor your lifestyle and regularly undergo preventive examinations.

Liver anatomy

According to the classification, the liver is divided into independent segments. Each is connected to a vascular inflow, outflow, and bile duct. In the liver, the portal vein, hepatic artery and bile duct are divided into branches, which in each of its segments are collected in veins.

The organs are made up of the blood vessels that lead and outflow. The main adductor vein that functions in the liver is the portal vein. The hepatic veins are referred to as discharge veins. Sometimes there are cases when these vessels flow into the right atrium on their own. Basically, the veins of the liver flow into the inferior vena cava.

Permanent venous vessels of the liver include:

• right vein;
• middle vein;
• left vein;
• the vein of the caudate lobe.

Portal

The portal or portal vein of the liver is a large vascular trunk that collects blood that passes through the stomach, spleen, and intestines. After collection, it delivers this blood to the lobes of the liver and transfers the already purified blood back to the general channel.

Normally, the length of the portal vein is 6-8 cm, and its diameter is 1.5 cm.

This blood vessel takes its origin behind the head of the pancreas. There, three veins merge: the inferior mesenteric vein, the superior mesenteric vein, and the splenic vein. They make up the roots of the portal vein.

In the liver, the portal vein is divided into branches, diverging along all hepatic segments. They accompany the branches of the hepatic artery.

The blood that is carried by the portal vein saturates the organ with oxygen, delivers vitamins and minerals to it. This vessel plays an important role in digestion and detoxifies the blood. In the event of a violation of the functioning of the portal vein, serious pathologies arise.

Hepatic vein diameter

The largest of the liver vessels is the right vein, the diameter of which is 1.5-2.5 cm. Its confluence into the inferior cavity occurs in the region of its anterior wall near the opening in the diaphragm.

Normally, the hepatic vein, formed by the left branch of the portal vein, flows at the same level as the right, only on the left side. Its diameter is 0.5-1 cm.

The diameter of the vein of the caudate lobe in a healthy person is 0.3-0.4 cm. Its mouth is slightly below the place where the left vein flows into the inferior cavity.

As you can see, the sizes of the hepatic veins differ from each other.

The right and left, passing through the liver, collect blood from the right and left hepatic lobes, respectively. The middle and the vein of the caudate lobe are from the lobes of the same name.

Portal hemodynamics

According to the course of anatomy, arteries pass through many organs of the human body. Their function is to saturate the organs with the substances they need. Arteries bring blood to the organs, and veins take it out. They transport the processed blood to the right side of the heart. This is how the large and small circles of blood circulation work. The hepatic veins play a role in it.

The gate system functions specifically. The reason for this is its complex structure. From the main trunk of the portal vein, there are many branches to venules and other bloodstreams. That is why the portal system, in fact, constitutes another additional circle of blood circulation. It cleans the blood plasma from harmful substances such as decay products and toxic components.

The portal vein system is formed by the union of large vein trunks near the liver. From the intestine, the blood is carried by the superior mesenteric and inferior mesenteric veins. The splenic vessel leaves the organ of the same name and receives blood from the pancreas and stomach. It is these large veins, merging, that become the basis of the black vein system.

Near the entrance to the liver, the trunk of the vessel, dividing into branches (left and right), diverges between the lobes of the liver. In turn, the hepatic veins are divided into venules. A network of small veins covers all the lobes of the organ inside and outside. After contact between blood and soft tissue cells occurs, these veins carry blood to the central vessels that extend from the middle of each lobe. After this, the central venous vessels are united into larger ones, from which the hepatic veins are formed.

blockage of the liver?

Hepatic vein thrombosis is called liver pathology. It is caused by a violation of internal circulation and the formation of blood clots, which block the outflow of blood from the organ. Mainstream medicine also calls it Budd-Chiari Syndrome.

Thrombosis of the hepatic veins is characterized by partial or complete narrowing of the lumens of the blood vessels, resulting from the action of a thrombus. Most often it occurs in those places where the mouth of the liver vessels is located and they flow into the vena cava.

If there are any obstacles in the liver to the outflow of blood, the pressure in the blood vessels rises and the hepatic veins expand. Although the vessels are very elastic, too high a pressure can rupture them, resulting in potentially fatal internal bleeding.

The question of the origin of hepatic vein thrombosis has not yet been closed. Experts on this issue were divided into two camps. Some consider thrombosis of the veins of the liver to be an independent disease, while others argue that it is a secondary pathological process caused as a result of a complication of the underlying disease.

The first case includes thrombosis, which arose for the first time, that is, we are talking about Budd-Chiari disease. The second case includes Budd-Chiari syndrome, which manifested itself due to a complication of the primary disease, which is considered the main one.

Due to the difficulty in dividing the measures for the diagnosis of these processes, the medical community usually calls the circulatory disorders of the liver not a disease, but a syndrome.

Causes of hepatic vein thrombosis

Blood clots in the liver are caused by:

1. Protein S or C deficiency.
2. Antiphospholipid syndrome.
3. Changes in the body associated with pregnancy.
4. Long-term use of oral contraceptives.
5. Inflammatory processes in the intestines.
6. Connective tissue diseases.
7. Various injuries of the peritoneum.
8. The presence of infections - amebiasis, hydatid cysts, syphilis, tuberculosis, etc.
9. Tumor invasions of the veins of the liver - carcinoma or renal cell carcinoma.
10. Hematological diseases - polycythemia, paroxysmal nocturnal hemoglobinuria.
11. Hereditary predisposition and congenital malformations of the hepatic veins.

The development of Budd-Chiari syndrome usually lasts from several weeks to months. Against its background, cirrhosis and portal hypertension often develop.

Symptoms

If unilateral hepatic obstruction develops, no special symptoms are observed. directly depends on the stage of development of the disease, the place in which the blood clot formed, and the complications that have arisen.

Often, Budd-Chiari syndrome is characterized by a chronic form that is not accompanied by symptoms for a long time. Sometimes signs of hepatic thrombosis can be detected by palpation. The disease itself is diagnosed exclusively as a result of instrumental research.

Chronic blockage is characterized by symptoms such as:

• Slight pain in the right hypochondrium.
• Feeling nauseous, sometimes accompanied by vomiting.
• Discoloration of the skin - yellowing appears.
• The sclera of the eyes turn yellow.

Jaundice is not required. In some patients, it may be absent.

Symptoms of acute blockage are more pronounced. These include:

• Suddenly onset vomiting, in which blood gradually begins to appear as a result of a rupture in the esophagus.
• Severe epigastric pain.
• The progressive accumulation of free fluids in the peritoneal cavity, which occurs due to venous stasis.
• Sharp pain all over the abdomen.
• Diarrhea.

In addition to these symptoms, the disease accompanies an enlargement of the spleen and liver. For acute and subacute forms of the disease, liver failure is characteristic. There is also a fulminant form of thrombosis. It is extremely rare and dangerous in that all symptoms develop very quickly, leading to irreparable consequences.

Diagnostics of the blockage of the hepatic vessels

A clear clinical picture is characteristic of Budd-Chiari syndrome. This makes the diagnosis much easier. If the patient has an enlarged liver and spleen, there are signs of fluids in the peritoneal cavity, and laboratory tests indicate overestimated blood coagulability, first of all, the doctor begins to suspect the development of thrombosis. However, he is obliged to study the patient's history very carefully.

There are good reasons to suspect a patient with thrombosis include the following signs:

In addition to the fact that the doctor studies the medical history and conducts a physical examination, the patient needs to donate blood for general and biochemical analysis, as well as for coagulation. You also need to take a liver test.

For the accuracy of the diagnosis, the following examination methods are used:

• ultrasound examination;
• portal vein radiography;
• contrast study of blood vessels;
• computed tomography (CT);
• magnetic resonance imaging (MRI).

All these studies make it possible to assess the degree of enlargement of the liver and spleen, the severity of vascular damage, and to find the location of the thrombus.

Complications

If the patient goes to a doctor late or if the changes resulting from thrombosis are diagnosed late, the risk of complications increases. These include:

• liver failure;
• portal hypertension;
• hepatocellular carcinoma;
• ascites;
• encephalopathy;
• bleeding from an enlarged hepatic vein;
• porosystemic collateraia;
• mesenteric thrombosis;
• bacterial peritonitis;
• liver fibrosis.

Treatment

In medical practice, two methods of treating Budd-Chiari syndrome are used. One of them is medication, and the second is with the help of surgical intervention. The disadvantage of drugs is that it is impossible to cure completely with their help. They only give a short-term effect. Even in the case of a timely visit of a patient to a doctor and treatment with drugs, almost 90% of patients die within a short period of time without the intervention of a surgeon.

The main goal of therapy is to eliminate the main causes of the disease and, as a result, restore blood circulation in the area of ​​thrombosis.

Drug therapy

In order to remove excess fluid from the body, doctors prescribe drugs with a diuretic effect. To prevent further development of thrombosis, the patient is prescribed anticoagulants. Corticosteroids are used to relieve abdominal pain.

In order to improve the characteristics of the blood and accelerate the resorption of the formed thrombi, fibrinolytics and antiplatelet agents are used. In parallel, supportive therapy is carried out aimed at improving metabolism in liver cells.

Surgical therapy

Conservative treatment methods for a diagnosis associated with thrombosis cannot provide the desired result - restoration of normal circulation in the affected area. In this case, only radical methods will help.

1. Establish anastomoses (artificial synthetic messages between vessels that allow blood circulation to be restored).
2. Place a prosthesis or mechanically dilate a vein.
3. Place a shunt to lower blood pressure in the portal vein.
4. Liver transplant.

In the case of a fulminant course of the disease, practically nothing can be done. All changes are happening very quickly, and doctors simply do not have time to take the necessary measures.

Prophylaxis

All measures to prevent the development of Budd-Chiari syndrome are reduced to the fact that you need to regularly contact medical institutions in order to undergo, as a preventive measure, the necessary diagnostic procedures. This will help to timely detect and begin treatment of hepatic vein thrombosis.

There are no special preventive measures for thrombosis. There are only measures to prevent relapse of the disease. These include taking anticoagulants that thin the blood and undergoing examinations every 6 months after surgery.

The blood supply system to the abdominal organs is quite complex. This is due to a number of functions that the organs of the gastrointestinal tract perform and their high sensitivity to the absence of blood - ischemia. The large abundance of blood vessels that supply blood to the intestines and stomach is associated with a number of factors:

The portal vein is a large vessel that collects blood from all unpaired organs of the abdominal cavity (such as the duodenum, small and large intestines, stomach and spleen), lies in the thickness of the hepato-duodenal ligament and carries blood directly to the liver.

Due to this anatomical structure, this vessel collects blood that has been absorbed in different parts of the gastrointestinal tract, and brings it to the liver, which makes it possible to cleanse human blood from toxins and other unwanted metabolites that have entered the human body with food and water. Thus, blood from the digestive tract cannot enter the general bloodstream, bypassing the main filter of the body - the liver.

In Latin, which is used for anatomical terms by body builders and doctors, the portal vein is called vena portae. From this term comes the name of a number of pathological processes inherent in this vessel - portal hypertension, portal thrombosis, portal cirrhosis, etc.

Anatomical and histological structure

The portal vein itself is anatomically quite simple - it is a thick vascular trunk that enters the liver. Such a vein has a very thick wall with a developed adventitia (connective tissue) layer, which allows it to withstand a pressure several times higher than the norm for such vessels in a number of pathologies.

When studying the anatomy of a vessel, studying pathological processes, etc., the portal vein is not considered in isolation, but it is said that there is a portal vein system.

At the level of the head of the pancreas, the portal vein receives two powerful vascular trunks - the superior and inferior mesenteric veins, which carry blood from the intestines, as well as the splenic vein.

Further, the left and right gastric venous trunks flow into the vessel, practically at the level of its entry into the gate of the liver. In the liver, the vessel breaks up into small branches that surround such structural units as liver lobules, forms the central vessels of the lobules, which then carry the blood purified by the liver into the inferior vena cava and the right parts of the human heart.

Portal vein thrombosis and other pathological processes lead to a sharp increase in blood pressure in all vessels that belong to the v system. portae. This leads to the opening of the valves, the so-called anastomoses (port-caval, cava-caval), which leads to the discharge of blood outside the liver into the general blood flow system.

The development of such anastomoses looks like an increase in the vasculature of the anterior abdominal wall ("medusa's head"), hemorrhoids with a corresponding clinical picture.

Therefore, pathologies such as portal vein thrombosis, tumors of the gastrointestinal tract, heart failure and all the causes that lead to cirrhosis of the liver must be diagnosed in a timely manner, all measures must be taken to prevent the development of portal hypertension and, as a consequence, a number of complications that lead to death.

Review of our reader - Alina Mezentseva

Recently I read an article that tells about the natural cream "Bee Spas Kashtan" for the treatment of varicose veins and cleaning blood vessels from blood clots. With this cream, you can FOREVER cure varicose veins, eliminate pain, improve blood circulation, increase the tone of veins, quickly restore the walls of blood vessels, cleanse and restore varicose veins at home.

I was not used to trusting any information, but I decided to check and ordered one package. I noticed the changes in a week: the pain went away, the legs stopped "buzzing" and swelling, and after 2 weeks the venous cones began to decrease. Try and you, and if anyone is interested, then below is the link to the article.

Diagnostics of the state of the vessel

The "gold standard" for both morphological and functional diagnostics of v. portae and liver vessels is an ultrasound scan (ultrasound) with Doppler blood flow. Ultrasound research allows you to evaluate the following indicators:

Doppler ultrasonography allows you to assess blood flow indicators not only in the vessels of the abdominal cavity, but also directly in the liver. Also, thanks to the Doppler, it is possible to estimate and calculate the approximate pressure in the vessel, which makes it possible to establish the diagnosis - portal hypertension. Diameter norm v. portae - no more than 13 mm. Portal pressure norm - 5-10 mm. rt. Art.

Less often, in cases of diagnosis of severe concomitant pathology (tumor process, trauma, etc.), CT examination is used. It allows you to assess the general morphology of organs and blood vessels, as well as detect a pathological process, which can often be beyond the reach of ultrasound sensors.

According to CT images, the doctor makes a reliable conclusion about whether the norm or pathology is present in the structure of the organ. Portal vein thrombosis can also be detected on CT.

Diseases

Pathological processes affecting the vascular system of the liver and abdominal cavity often have a poor prognosis. This is due to the fact that the mechanisms of development of diseases often lead to liver and heart failure. Among all diseases affecting the vessel, such diseases are the leading ones.