Superior mesenteric vein. Acute disorders of mesenteric circulation
Portal vein, v. portae hepatis , collects blood from unpaired abdominal organs.
It is formed behind the head of the pancreas as a result of the confluence of three veins: the inferior mesenteric vein, v. mesenterica inferior, superior mesenteric vein, v. mesenterica superior, and splenic vein, v. splenica
The portal vein from the place of its formation goes up and to the right, passes behind the upper part of the duodenum and enters the hepatoduodenal ligament, passes between the layers of the latter and reaches the gate of the liver.
In the thickness of the ligament, the portal vein is located with the common bile and cystic ducts, as well as with the common and proper hepatic arteries in such a way that the ducts occupy the extreme position on the right, the arteries are to the left, and behind the ducts and arteries and between them is the portal vein.
At the gate of the liver, the portal vein is divided into two branches - right and left, respectively, to the right and left lobes of the liver.
Right branch, r. dexter, wider than left; it enters through the portal of the liver into the thickness of the right lobe of the liver, where it is divided into anterior and posterior branches, r. anterior et r. posterior.
Left branch, r. sinister, longer than right; heading to the left side of the gate of the liver, it, in turn, along the way is divided into a transverse part, pars transversa, giving branches to the caudate lobe - caudal branches, rr. caudati, and the umbilical part, pars umbilicalis, from which the lateral and medial branches extend, rr. laterales et mediales, into the parenchyma of the left lobe of the liver.
Three veins: inferior mesenteric, superior mesenteric and splenic, from which v. is formed. portae are called the roots of the portal vein.
In addition, the portal vein receives the left and right gastric veins, vv. gastricae sinistra et dextra, prepyloric vein, v. prepylorica, periumbilical veins, vv. paraumbilicales, and gallbladder vein, v. cystica.
1. 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.
It begins in the pelvic cavity as the superior rectal vein, v. rectalis superior, and in the wall of the rectum its branches are connected with the rectal venous plexus, plexus venosus rectalis.
The superior rectal vein runs upward, crosses the iliac vessels in front at the level of the left sacroiliac joint and receives the sigmoid veins, vv. sigmoideae, which follow from the wall of the sigmoid colon.
The inferior mesenteric vein is located retroperitoneally and, heading upward, forms a small arc with its convexity facing to the left. Taking the left colic vein, v. colica sinistra, the inferior mesenteric vein deviates to the right, passes immediately to the left of the duodenojejunal flexure under the pancreas and most often connects with the splenic vein. Sometimes the inferior mesenteric vein drains directly into the portal vein.
2. Superior mesenteric vein, v. mesenterica superior , collects blood from the small intestine and its mesentery, the cecum and appendix, 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 its branches accompany all the branches of this artery.
The superior mesenteric vein begins in the region of the ileocecal angle, where it is called the ileocolic vein.
Ileocolic vein, v. ileocolica, collects blood from the terminal ileum, the appendix (vein of the appendix, v. appendicularis) and the cecum. Heading upward and to the left, the ileocolic vein directly continues into the superior mesenteric vein.
The superior mesenteric vein is located at the root of the mesentery of the small intestine and, forming an arch with a convexity to the left and down, receives a number of veins:
a) jejunal and ileal veins, vv. jejunales et ileales, 16-20 in total, go to the mesentery of the small intestine, where with their branches they accompany the branches of the small intestinal arteries. The intestinal veins drain into the superior mesenteric vein on the left;
b) right colic veins, vv. colicae dextrae, go retroperitoneally from the ascending colon and anastomose with the ileocolic and middle colic veins;
c) middle colic vein, v. colica media, located between the layers of the mesentery of the transverse colon; it collects blood from the right flexure of the colon and the transverse colon. In the area of the left flexure of the colon, it anastomoses with the left colic vein, v. colica sinistra, forming a large arcade;
d) right gastroepiploic vein, v. gastroepiploica dextra, accompanies the artery of the same name along the greater curvature of the stomach; collects blood from the stomach and greater omentum; at the level of the pylorus it flows into the superior mesenteric vein. Before entering, it receives the pancreatic and pancreaticoduodenal veins;
e) pancreaticoduodenal veins, vv. pancreaticoduodenales, repeating the path of the arteries of the same name, collect blood from the head of the pancreas and duodenum;
e) pancreatic veins, vv. pancreaticae, depart from the parenchyma of the head of the pancreas, passing into the pancreaticoduodenal veins.
3. Splenic vein, v. splenica , collects blood from the spleen, stomach, pancreas and greater omentum.
It is formed in the area of the hilum of the spleen from numerous veins emerging from the substance of the spleen.
Here the splenic vein receives the left gastroepiploic vein, v. gastroepiploica sinistra, which accompanies the artery of the same name and collects blood from the stomach, greater omentum, and short gastric veins, vv. gastricae breves, carrying blood from the fundus of the stomach.
From the hilum of the spleen, the splenic vein runs to the right along the upper edge of the pancreas, located below the artery of the same name. It crosses the anterior surface of the aorta immediately above the superior mesenteric artery and merges with the superior mesenteric vein to form the portal vein.
The splenic vein receives the pancreatic veins, vv. pancreaticae, mainly from the body and tail of the pancreas.
In addition to the indicated veins that form the portal vein, the following veins flow directly into its trunk:
a) prepyloric vein, v. prepylorica, begins in the pyloric region of the stomach and accompanies the right gastric artery;
b) gastric veins, left and right, v. gastrica sinistra et v. gastrica dextra, They run along the lesser curvature of the stomach and accompany the gastric arteries. In the area of the pylorus, the veins of the pylorus flow into them, in the area of the cardial part of the stomach - the veins of the esophagus;
c) periumbilical veins, vv. paraumbilicales (see Fig. 829, 841), begin in the anterior abdominal wall in the circumference of the umbilical ring, where they anastomose with the branches of the superficial and deep superior and inferior epigastric veins. Heading to the liver along the round ligament of the liver, the peri-umbilical veins either unite into one trunk or flow into the portal vein in several branches;
d) gallbladder vein, v. cystica, flows into the portal vein directly in the substance of the liver.
In addition, in this area in v. portae hepatis drains a number of small veins from the walls of the portal vein itself, the hepatic arteries and liver ducts, as well as veins from the diaphragm, which reach the liver along the falciform ligament.
The superior mesenteric artery (a. mesenterica superior) is a large vessel that supplies blood to most of the intestine and the pancreas. The origin of the artery varies within the XII thoracic - II lumbar vertebrae. The distance between the orifices of the celiac trunk and the superior mesenteric artery varies from 0.2 to 2 cm.
Coming from under the lower edge of the pancreas, the artery goes down and to the right and, together with the superior mesenteric vein (to the left of the latter), lies on the anterior surface of the ascending part of the duodenum. Descending along the root of the mesentery of the small intestine towards the ileocecal angle, the artery gives off numerous jejunal and ileal arteries, which pass into the free mesentery. The two right branches of the superior mesenteric artery (ileocolic and right colon), heading to the right part of the colon, together with the veins of the same name, lie retroperitoneally, directly under the peritoneal layer of the bottom of the right sinus (between the parietal peritoneum and Toldt’s fascia). Regarding the syntopy of various parts of the trunk of the superior mesenteric artery, it is divided into three sections: I - pancreas, II - pancreas-duodenal, III - mesenteric.
The pancreatic section of the superior mesenteric artery is located between the legs of the diaphragm and, heading anterior to the abdominal aorta, pierces the prerenal fascia and Treitz's fascia.
The pancreatic-duodenal section is located in a venous ring formed from above by the splenic vein, below by the left renal vein, on the right by the superior mesenteric vein, and on the left by the inferior mesenteric vein at the place of its confluence with the splenic vein. This anatomical feature of the location of the second section of the superior mesenteric artery determines the cause of arterio-mesenteric intestinal obstruction due to compression of the ascending part of the duodenum between the aorta at the back and the superior mesenteric artery at the front.
The mesenteric section of the superior mesenteric artery is located in the mesentery of the small intestine.
Variants of the superior mesenteric artery are combined into four groups: I - branching of branches usual for the superior mesenteric artery from the aorta and celiac trunk (absence of the trunk of the superior mesenteric artery), II - doubling of the trunk of the superior mesenteric artery, III - branching of the superior mesenteric artery by a common trunk with the celiac artery, IV - the presence of supernumerary branches extending from the superior mesenteric artery (common hepatic, splenic, gastroduodenal, right gastroepiploic, right gastric, transverse pancreatic, left colon, superior rectal) [Kovanov V.V., Anikina T.I., 1974].
Visceral branches: middle adrenal and renal arteries
Middle adrenal artery (a. supra-renalis media) - a small paired vessel extending from the side wall of the upper aorta, slightly below the origin of the superior mesenteric artery. It goes outward, towards the adrenal gland, crossing transversely the lumbar pedicle of the diaphragm. It may originate from the celiac trunk or from the lumbar arteries.
Renal artery (a. renalis) - paired, powerful short artery. Starts from the lateral wall of the aorta almost at a right angle to it at the level I-II lumbar vertebra. The distance from the origin of the superior mesenteric artery varies within 1-3 cm. The trunk of the renal artery can be divided into three sections: periaortic, middle, perinephric. The right renal artery is slightly longer than the left because the aorta lies to the left of the midline. Heading towards the kidney, the right renal artery is located behind the inferior vena cava and crosses the spine with the thoracic lymphatic duct lying on it. Both renal arteries, on the way from the aorta to the renal hilum, cross the medial legs of the diaphragm in front. Under certain conditions, variations in the relationship of the renal arteries with the medial crura of the diaphragm can cause the development of renovascular hypertension (abnormal development of the medial crura of the diaphragm, in which the renal artery appears posterior to it). Except
In addition, the abnormal location of the renal artery trunk anterior to the inferior vena cava can lead to congestion in the lower extremities. From both renal arteries the thin inferior suprarenal arteries extend upward and the ureteric branches extend downward (Fig. 26).
Rice. 26. Branches of the renal artery. 1 - middle adrenal artery; 2 - inferior adrenal artery; 3 - renal artery; 4 - ureteral branches; 5 - posterior branch; 6 - anterior branch; 7 - artery of the lower segment; 8 - artery of the lower anterior segment; 9 - artery of the upper anterior segment; 10 - artery of the upper segment; 11 - capsular arteries. Quite often (15-35% of cases reported by different authors) accessory renal arteries are found. All their diversity can be divided into two groups: arteries entering the hilus of the kidney (accessory hilus) and arteries penetrating the parenchyma outside the hilum, often through the upper or lower pole (additional polar or perforating). The arteries of the first group almost always arise from the aorta and run parallel to the main artery. In addition to the aorta, polar (perforating) arteries can also arise from other sources (common, external or internal iliac, adrenal, lumbar) [Kovanov V.V., Anikina T.I., 1974].
1. Superior mesenteric artery, a mesenterial superior. Unpaired branch of the abdominal aorta. It begins approximately 1 cm below the celiac trunk, first lies behind the pancreas, then passes in front of the uncinate process. Its branches continue into the mesentery of the small and transverse colon. Rice. A, B.
2. Inferior pancreaticoduodenal artery pancreaticoduodenalis inferior. It arises at the level of the upper edge of the horizontal part of the duodenum. Its branches lie in front and behind the head of the pancreas. Rice. A. 2a Anterior branch, ramus anterior. Anastomoses with the anterior superior pancreaticoduodenal artery. Rice. IN.
3. Jejunal arteries, aajejunales. Goes to the jejunum in its mesentery. Rice. A.
4. Ileal arteries, aa ileales. They approach the ileum between the two layers of its mesentery. Rice. A.
5. Ileocolic artery, a. ileocolica. In the mesentery of the small intestine it goes down and to the right to the iliocecal angle. Rice. A.
6. Colon branch, ramus colicus. It goes to the ascending colon. Anastomoses with the right colon artery. Rice. A.
7. Anterior cecal artery, a. caecalis (cecalis) anterior. In the cecal fold it approaches the anterior surface of the cecum. Rice. A.
8. Posterior cecal artery, a. caecalis (cecalis) posterior. It goes behind the final section of the ileum to the posterior surface of the cecum. Rice. A.
9. Artery of the vermiform appendix, a. appendicularis. It crosses the ileum posteriorly and lies along the free edge of the mesentery of the appendix. The origin of the artery is not constant; it can be double. Rice. A. 9a Ileal branch, ramus ile: alis. It goes to the ileum and anastomoses with one of the small intestinal arteries. Rice. A.
10. Right colic artery, a. Colica dextra. Anastomoses with the ascending branch of the ileocolic and middle colic arteries. Rice. A. 10a Artery of the right flexure of the colon, aflexura dextra. Rice. A.
11. Middle colic artery, a. Colica media. Located in the mesentery of the transverse colon. Rice. A. Pa Marginal colic artery, a. marginalis coli []. Anastomosis of the left colon and sigmoid arteries. Rice. B.
12. Inferior mesenteric artery, and tesenterica inferior. Departs from the abdominal aorta at the level of L3 - L4. It goes to the left and supplies the left third of the transverse colon, descending, sigmoid colon, as well as most of the rectum. Rice. B. 12a Ascending [intermesenteric] artery, a ascendeus. Anastomoses with the left colic and middle colic arteries. Rice. A, B.
13. Left colic artery, a. Colica sinistra. Retroperitoneally directed to the descending colon. Rice. B.
14. Sigmoid intestinal arteries, aa. sigmoideae. It goes obliquely down to the wall of the sigmoid colon. Rice. B.
15. Superior rectal artery, a. rectalis superior. Behind the rectum it enters the small pelvis, where it is divided into right and left branches, which, perforating the muscle layer, supply blood to the intestinal mucosa to the anal valves. Rice. B.
16. Middle adrenal artery, and suprarenalis (adrenalis) media. It arises from the abdominal aorta and supplies blood to the adrenal gland. Rice. IN.
17. Renal artery, a. renalis. It starts from the aorta at level L 1 and is divided into several branches that go to the gate of the kidney. Rice. B, D. 17a Capsular arteries, aaxapsulares (perirenales). Rice. IN.
18. Inferior adrenal artery, a. suprarenalis inferior. Participates in the blood supply to the adrenal gland. Rice. IN.
19. Anterior branch, ramus anterior. Supplies blood to the upper, anterior and lower segments of the kidney. Rice. V, G.
20. Artery of the upper segment, a. segment superioris. Spreads to the posterior surface of the kidney. Rice. IN.
21. Artery of the upper anterior segment, a.segmenti anterioris superioris. Rice. IN.
22. Artery of the lower anterior segment, a segmenti anterioris inferioris. Branch to the anterioinferior segment of the kidney. Rice. IN.
23. Artery of the lower segment, a. segmenti inferioris. Spreads to the posterior surface of the organ. Rice. IN.
Superior mesenteric artery (a. mesenterica superior).
A. mesenterica superior, superior mesenteric artery, departs from the anterior surface of the aorta immediately below the vermiform trunk, goes down and forward, into the gap between the lower edge of the pancreas in front and the horizontal part of the duodenum behind, enters the mesentery of the small intestine and descends to the right iliac fossa .
Branches, a. mesentericae superioris:
a) a. pancreatieoduodeiialis inferior goes to the right along the concave side of the duodeni towards aa. pancreaticoduodenales superiores;
b) aa. intestinales -- 10-16 branches that extend from a. mesenterica superior to the left side to the jejunum (aa. jejundles) and ileum (aa. ilei) intestine; along the way they are divided dichotomously and adjacent branches are connected to each other, which is why it turns out along aa. jejunales three rows of arcs, and along aa. ilei - two rows. The arches are a functional device that ensures blood flow to the intestines with any movements and positions of its loops. Many thin branches extend from the arches, which encircle the intestinal tube in a ring;
c) a. ileocolica extends from a.r mesenterica superior to the right, supplying the lower portion of the intestinum ileum and the cecum with branches and sending them to the vermiform appendix a. appendicularis, passing behind the final segment of the ileum;
d) a. colica dextra goes behind the peritoneum to the colon ascendens and near it is divided into two branches: ascending (goes upward to meet a. colica media) and descending (descends to meet a. ileocolica); branches extend from the resulting arches to the adjacent parts of the colon;
e) a. Colica media passes between the leaves of the mesocolon transversum and, having reached the transverse colon, is divided into right and left branches, which diverge in the corresponding directions and anastomose: the right branch - with a. colica dextra, left - with a. colica sinistra
Inferior mesenteric artery (a. mesenterica inferior).
A. mesenterica inferior, the inferior mesenteric artery, departs at the level of the lower edge of the third lumbar vertebra (one vertebra above the division of the aorta) and goes down and slightly to the left, located behind the peritoneum on the anterior surface of the left lumbar muscle.
Branches of the inferior mesenteric artery:
a) a. colica sinistra is divided into two branches: the ascending one, which goes towards the flexura coli sinistra towards a. colica media (from a. mesenterica superior), and descending, which connects to aa. sigmoideae;
b) aa. sigmoideae, usually two to the colon sigmoideum, with ascending branches anastomose with the branches of a. colica sinistra, descending - with
c) a. rectalis superior. The latter is a continuation of a. mesenterica inferior, descends at the root of the mesentery colon sigmoideum into the small pelvis, crossing a. iliaca communis sinistra, and splits into lateral branches towards the rectum, which enter into connection with both aa. sigmoideae, as well as with a. rectalis media (from a. iliaca interna).
Thanks to the interconnection of the branches of aa. colicae dextra, media et sinistra and aa. rectales from a. iliaca interna the large intestine along its entire length is accompanied by a continuous chain of anastomoses connected to each other.
Paired visceral branches: renal artery (a. renalis), middle adrenal artery (a. suprarenalis media).
Paired visceral branches depart in the order of arrangement of organs determined by their anlage.
1. A. suprarenalis media, middle adrenal artery, starts from the aorta near the beginning of a. mesenterica superior and goes to gl. suprarenalis.
2. A. renalis, the renal artery, departs from the aorta at the level of the II lumbar vertebra almost at a right angle and goes in a transverse direction to the gate of the corresponding kidney. The caliber of the renal artery is almost equal to the superior mesenteric artery, which is explained by the urinary function of the kidney, which requires a large blood flow. The renal artery sometimes departs from the aorta with two or three trunks and often enters the kidney with multiple trunks, not only in the hilum area, but along the entire medial edge, which is important to consider when preliminary ligation of the arteries during kidney removal surgery. At the hilum of the kidney a. renalis is usually divided into three branches, which in the renal sinus in turn break up into numerous branches (see "Kidney").
The right renal artery lies behind v. cava inferior, head of the pancreas and pars descendens duodeni, left - behind the pancreas. V. renalis is located in front and slightly below the artery. From a. renalis extend upward to the lower part of the adrenal gland a. suprarenalis inferior, as well as a branch to the ureter.
3. A. testucularis (in women a. ovarica) is a thin long stem that starts from the aorta immediately below the beginning of a. renalis, sometimes from this last one. Such a high origin of the artery supplying the testicle is caused by its origin in the lumbar region, where a. testicularis occurs at the shortest distance from the aorta. Later, when the testicle descends into the scrotum, a. testicularis, which at the time of birth descends along the anterior surface of m. psoas major, gives off a branch to the ureter, approaches the internal ring of the inguinal canal and, together with the ductus deferens, reaches the testicle, which is why it is called a. testicularis. The woman has the corresponding artery, a. ovarica, is not directed to the inguinal canal, but goes to the small pelvis and further as part of the lig. suspensorium ovarii to the ovary.
Parietal branches of the abdominal aorta: inferior phrenic artery (a. phrenica inferior), lumbar arteries (Aa. lumbales), median sacral artery (a. sacralis mediana).
1. A. phrenica inferior, the inferior phrenic artery, supplies blood to the pars lumbalis of the diaphragm. She gives a small twig, a. suprarenalis superior, to the adrenal gland.
2. Ah. lumbales, lumbar arteries, usually four on each side (the fifth sometimes arises from a. sacralis mediana), correspond to the segmental intercostal arteries of the thoracic region. They supply blood to the corresponding vertebrae, spinal cord, muscles and skin of the lumbar and abdominal areas.
3. A. sacralis mediana, the median sacral artery, unpaired, represents a developmentally delayed extension of the aorta (caudal aorta).
