Home Preparations for the winter What is the mesentery of the small intestine. Mesentery of the intestine. Duplication of the peritoneum. Mesentery of the small intestine

Preparations for the winter

What is the mesentery of the small intestine. Mesentery of the intestine. Duplication of the peritoneum. Mesentery of the small intestine

One of the varieties of duplications that provide fixation of organs to the walls is the mesentery. There are also other duplications, which are commonly called folds, ligaments and omentums.

One of the most important functions in the abdominal cavity is performed by the peritoneum. It prevents the spread of infectious processes, is an impenetrable barrier to toxic substances and normalizes bowel activity and much more.

The peritoneum is a bag that hermetically envelops the internal organs (consists of a basement membrane and mesothelium). Passing from the walls of the abdomen to the internal organs, it forms ligaments, folds, omentums, in which blood, lymphatic vessels and nerve trunks pass.

The main task is to isolate the internal organs from the cavity. This explains the fact that most often purulent processes (for example, appendicular infiltrate) are localized.

The peritoneum covering the walls of the abdomen is called the parietal, and, moving to the organs, it is called the visceral. Between these sheets there is a small amount of serous fluid, which acts as a lubricant.

Main functions:

excretion and absorption of transudate;
isolation of purulent processes;
fixation of organs;
immune protection.

What is duplication and its types

The peritoneum covers the anterior wall, after which it follows into the pelvic cavity, where it passes to the bottom of the bladder, to the uterus (in women) and the rectum, after which it passes to the intestinal loops.

It is important to understand that in places where the peritoneum passes to the organs, so-called dulicatures (doublings) are formed. They are intended for fixation of organs. Most often, duplications contain adipose tissue, blood vessels and nerves.

There are such duplicates:

mesentery;
ligaments;
folds;
oil seals.

What is a mesentery?

So, the mesentery is a duplication of sheets, which ensures the fixation of intestinal loops to the back wall. This element is found in the small intestine, in some cases in the caecum and sigmoid colon, as well as the fallopian tubes.

Some types of mesentery of the intestines:

Thin - called the mesenterium - consists of 2 layers that go from the loops of the jejunum and ileum in the direction of the II lumbar vertebra, where the point of its fixation (root) is located. In order to find the beginning of the mesentery in surgery, a fairly simple technique is used - it is necessary to find the transition from the duodenum to the jejunum (Treitz's ligament). The mesenterium is directed from left to right (about 9 cm long), as a result of which two sinuses (spaces) are formed in the cavity - the right and left mesenteric sinuses. In pathological conditions, the length of the mesentery may increase. It crosses the aorta and the inferior vena cava in front, and in its composition passes the superior mesenteric vein and artery, lymphatic vessels that feed the intestinal walls and splanchnic nerves.
Blind - has a similar structure and occurs in 80% of cases. It should be noted that sometimes it extends to the appendicular process (mesoappendix). The mesentery contains branches of the superior mesenteric artery, lymphatic vessels and nerve trunks.
Transverse colon - divides the abdominal cavity into the upper and middle floors. Its root is fixed in the region of the upper edge of the II lumbar vertebra. It goes to the posterior surface of the transverse colon, after which it continues into the greater omentum.
Sigmoid - fixes the distal parts of the large intestine. The length of the mesosigmoid decreases from top to bottom, so the upper and middle sections are more mobile.
The mesentery of the fallopian tubes (mesosalpinx) - provides fixation of the appendages to the walls of the small pelvis.

What are folds?

Also, among duplications, attention should be paid to the folds, where pus, blood, and exudate most often accumulate. They form in places where the peritoneum covers large vessels, ligaments and ducts.

It is necessary to highlight such folds as:

external, middle and median umbilical fold, in which the vessels and ligaments of the same name pass;
upper and lower duodenal fold - at the transition to the duodenum 12;
ileocecal and caecal fold - in places of transition to the same sections of the intestine.

What are the ligaments of the peritoneum?

Another type of duplication is bundles. In the abdominal cavity, they perform a fixation function, and are also part of many anatomical formations. They are formed during embryogenesis, when the relationship between the intestine and the peritoneum changes.

Main links:

hepato-gastric - connects the gates of the liver with the lesser curvature of the stomach (it contains the nerves of Lateger and gastric arteries);
hepatic-duodenal - located between the gates of the liver and the duodenum 12 (portal vessels and the bile duct pass through it);
gastrocolic - reports a large curvature of the stomach and upper colon;
gastro-splenic-participates in the formation of the greater omentum;
gastro-diaphragmatic - closes access to the left paracolic sinus.

It is possible to single out at least 10 different ligaments involved in the formation of the Winslow hole and providing fixation of various organs.

The most important formations of the abdominal cavity should also include omentums, which are a double duplication. They are also commonly called abdominal orderlies, since they limit organs in the form of an apron.

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The structure of the posterior abdominal wall is the key to understanding the relationship between the large intestine and the rest of the abdominal organs. The outer border of the abdominal cavity is the intra-abdominal fascia, which covers the muscles of the posterior wall (Fig. 1). Large vessels and urinary structures pass between the intra-abdominal fascia and the posterior parietal peritoneum and are surrounded by an intermediate fascia (Gerota). Note the ureters running along the upper psoas near the spine and crossing the bifurcations of the common iliac vessels.

During the formation of the omental sac and rotation of the middle section of the primary intestine, the duodenum and pancreas lie on the deepest abdominal structures (vessels, ureters) (Fig. 2). As a result of fixation of the rotated colon to the underlying structures, two delta-shaped sections of the fused fascia are formed on the right and left sides, and the root of the mesentery of the transverse and colon runs diagonally and crosses the second section of the duodenum and the pancreas (Fig. 3). The root of the mesentery of the sigmoid colon crosses the left iliac vessels and the ureter.

The mesentery of the transverse colon is shortened at the corners, but elongated in the center, which allows the transverse colon to hang down freely in a vertical position of the body (Fig. 4). On this wide surface of the mesentery, the hanging distal stomach is placed (Fig. 5). The gastrocolic ligament is formed from the anterior layers of the greater omentum, in which the gastroepiploic vascular arcades pass.

By examining successive transverse sections of the abdomen, one can better understand the anatomy and position of the large intestine (Fig. 6). As can be seen in the figure, the splenic angle is always (albeit to varying degrees) located above the hepatic angle. When introducing ports for mobilization of the left intestine, one should take into account the special significance of isolating this particular area. In the figure, the transverse colon is pubescent, and the sigmoid colon is shortened and straightened, but the latter is often excessively elongated. The redundancy of any of the sections of the intestine complicates laparoscopic manipulations.

The large intestine refers to the organs of the digestive tract. This section of the gastrointestinal tract has the widest lumen. In the large intestine, the formation of feces is carried out, as well as the absorption of water from digested food residues. This organ is divided into 5 anatomical sections. One of them is the transverse colon. It is the central department. As in other parts of the large intestine, pathological processes can develop in it. This organ is treated by a gastroenterologist and a surgeon.

Anatomical structure of the transverse colon

The transverse section of the colon is located between the ascending and descending parts. It runs from the hepatic to the splenic flexure. The transverse section is located in the form of a loop. It may be above or below the level of the umbilical ring. In some cases, the transverse colon reaches the small pelvis. In terms of length, it is considered the longest (about 50 cm).

Inside this section is represented by a mucous membrane. Lines the transverse intestine with a cylindrical single-layer epithelium. The mucosal lamina is made up of fibrous connective tissue. It contains exocrine glands and accumulations of lymphoid cells. In the submucosal layer there are blood and lymphatic vessels, as well as nerves. The muscular layer is represented by smooth muscles. There are 3 sphincters throughout the transverse colon. The first is located in the proximal section, the second is in the middle part, the third is at the splenic flexure.

The mesentery of the transverse colon is located along the posterior wall of the abdomen. It contains blood and lymph vessels. The transverse colon is covered with peritoneum on all sides. Therefore, it refers to intraperitoneal anatomical formations.

The value of the transverse colon in the body

Transverse is median. It performs the following functions:

Development of a secret necessary for the formation of end products - excrement. Exocrine glands are involved in the breakdown of fiber.
Promotion of contents through the intestinal lumen. It is carried out due to the presence of special tapes - gaustra, as well as sphincters.
Absorption of fluid from chyme, fat-soluble vitamins, glucose and amino acids.

The transverse colon is of great importance, since all these functions are necessary for the digestive process. In the lumen of this section there are many bacteria that make up the normal microflora. They are necessary to maintain acid-base balance. In addition, the normal microflora is involved in the inactivation of pathogenic bacteria.

Transverse colon: topography

Above the transverse section of the large intestine are the digestive organs. Among them - the liver, gallbladder, spleen. Anteriorly, the transverse colon is adjacent to the anterior abdominal wall. Therefore, it is well accessible to palpation. The lower edge of the organ is adjacent to the loops of the small intestine. Behind is the pancreas, left kidney and duodenum. These anatomical formations are separated from the transverse colon by mesacolon - the mesentery. It provides blood supply and outflow of lymph from this department.

The omentum is located between the transverse colon and the greater curvature of the stomach. It forms a bond. The blood supply of the organ is carried out by branches from the superior and inferior mesenteric arteries.

Causes of pathologies of the transverse colon

The defeat of the transverse part of the colon can occur due to various reasons. In some cases, diseases are formed in early childhood or in the prenatal period. This is due to improper laying of fetal tissues. Other causes of pathologies include the following effects:

Mechanical damage to the intestinal mucosa.
Bacterial and viral infections.
Functional disorders resulting from neurological diseases.
Chemical influences.
The occurrence of neoplasms in the lumen of the transverse colon.
Acute and chronic circulatory disorders in the mesenteric vessels.
Chronic destructive processes.

All these causes lead to disruption of the functioning of the transverse colon. The result is indigestion. All pathological conditions require treatment. After all, in its absence, there is stagnation of feces and intoxication of the whole organism.

Diseases of the transverse colon

If abdominal pain occurs, attention should be paid to whether the transverse colon is affected. Damage symptoms can vary. Clinical manifestations depend on the pathological process that has developed in the patient. The following groups of diseases of the transverse colon are distinguished:

In early childhood, congenital pathologies of the intestine are found. These include Hirschsprung's disease, cystic fibrosis, megacolon.

Symptoms of pathologies of the transverse colon

The signs of diseases of the transverse colon include: pain, violation of the consistency of the stool and the act of defecation, symptoms of intoxication. Unpleasant sensations in the navel or slightly below its level can be observed in any pathological condition. If the disease is caused by pathogens of an intestinal infection, then they will be strongly pronounced. In this case, frequent loose stools are noted, which may contain various impurities - mucus, blood. In some infectious processes, the stool acquires a characteristic color and smell (in the form of "swamp mud", "frog spawn", "rice water"). Dysentery is characterized by severe cramps in the left abdomen and false urge to defecate.

In chronic inflammatory processes, discomfort in the abdomen, diarrhea, followed by stool retention, are periodically noted. Damage to the intestinal wall leads to the formation of bleeding ulcers.

Vascular disorders, stagnation of feces and congenital anomalies lead to the development of intestinal obstruction. This disease refers to acute surgical conditions. Regardless of the cause of the obstruction, help is required immediately.

Benign neoplasms in the intestine

A benign tumor of the transverse colon can arise from any tissue that makes up the wall of the organ. Varieties of this group of diseases include: polyp, myoma, fibroma, hemangioma. Benign neoplasms are characterized by the fact that they grow into the lumen of the organ without affecting the thickness of the wall. A common type of tumor is the polyp of the transverse colon. It is a small outgrowth facing the cavity of the organ. With a small size of the formation, the polyp may not manifest itself in any way. However, it must be removed. Due to the constant passage of feces through the intestine, a benign tumor is damaged, may bleed or become infected. There is a high risk that the polyp will "grow" into an oncological process.

Malignant tumors of the transverse colon

Cancer of the transverse colon affects the elderly, but can also develop in younger patients. Most often, it occurs against the background of chronic inflammatory pathologies, polyposis. The symptoms of cancer include pain, impaired stool, with large tumors - intestinal obstruction. In advanced cases, patients cannot eat, there is an increase in inguinal lymph nodes, fever, weight loss and weakness.

Transverse colon: treatment of pathologies

Treatment of diseases of the transverse colon can be conservative and operative. In the first case, antibacterial drugs are used (drugs "Ciprofloxacin", "Azithromycin"), anti-inflammatory drugs. Diarrhea is an indication for rehydration therapy. Fluid is administered in a variety of ways. If the patient's condition is satisfactory, they give alkaline mineral water, Regidron solution to drink. In severe cases, fluid is injected into a vein. With diarrhea, medicines "Smecta", "Hilak-forte" are prescribed, which contribute to the normalization of the intestines.

With destructive and oncological diseases, an operation is performed. It consists in resection of the transverse colon and suturing of the free ends. After surgery, it is necessary to follow a diet, since the restoration of organ functions does not occur immediately.

The mesenteric part of the small intestine is located in the lower part of the abdominal cavity, under the mesentery of the transverse colon (see Fig.,). It begins at the duodenal-skinny bend, to the left of the body of the I (II) lumbar vertebra. Its lower border is in the right iliac fossa at the level of the body of the IV lumbar vertebra. The diameter of the mesenteric part of the small intestine in the initial part is 4.8-5.0 cm, in the distal part - 2.7-3.0 cm. This entire part of the small intestine is located intraperitoneally, that is, it is covered on all sides by the visceral peritoneum, with the exception of a narrow strip of the place of attachment of the mesentery.

The mesenteric part of the small intestine, according to a number of features (see below), is divided into two sections: the proximal 2/5 of its length is jejunum, jejunum, distal 3/5 – ileum, ileum; there is no sharp boundary between them.

The loops of the small intestine have a more or less definite position and direction: 6-7 loops of the proximal section (jejunum) are located horizontally and occupy the upper left part of the lower floor of the abdominal cavity and the umbilical region; 7-8 loops of the distal section (ileum) are vertical, occupy the hypogastric, right iliac regions and the pelvic cavity. In the small pelvis, the last loops of the ileum are located before moving to the terminal section, as a result of which the latter has a direction from bottom to top and to the right (ascending) into the iliac fossa. In addition, the loops of the small intestine are arranged in two layers.

In the mesenteric part of the small intestine, there are two edges: mesenteric, by which the intestine is fixed to the mesentery, and the opposite is free. In the region of the mesenteric region, vessels and nerves approach the intestinal wall.

The walls of the mesenteric portion of the small intestine are composed of three layers: serous, muscular and mucous membranes (see Fig. , B).

Serous membrane, tunica serosa, fits the intestine from the outside on three sides, leaving only a narrow strip free along the mesenteric edge, where both sheets of the mesentery, approaching the intestinal wall, diverge on opposite sides of it.

The serous membrane is connected to the underlying muscular membrane by means of subserous base, tela subserosa.

Muscular membrane, tunica muscularis, consists of two layers of smooth muscle fibers: outer - longitudinal layer, stratum longitudinale, and internal - circular layer, stratum circulare.

Mucosa, tunica mucosa, consists of an epithelial cover with an underlying plate, own muscularis mucosa, lamina muscularis mucosae, and submucosa, tela submucosa. The mucous membrane forms circular folds, plicae circulares(see Fig. , ), has intestinal villi, villi intestinales, and crypts in which ducts open intestinal glands, glandulae intestinales, as well as lymphatic follicles, i.e., all those formations that (with the exception of the duodenal glands) are inherent in the mucous membrane of the duodenum. The difference in the structure of these formations is as follows: in the mesenteric part of the small intestine, the number of circular folds is less than in the duodenum, and from the jejunum to the ileum, their number gradually decreases, and there are almost none in the terminal section. The total number of folds in the small intestine ranges from 500 to 1200. In the same sequence (from the beginning to the end of the small intestine), the height of the folds also decreases.

The villi in the mesenteric part of the small intestine are thinner and somewhat shorter than in the duodenum. Their number decreases in the distal direction; in the jejunum their number reaches 30-40, in the ileum -18-30 per 1 mm2; their length and thickness also decrease.

The place where the ileum enters the blind ileocecal orifice, ostium ileoceale, it is bordered by a funnel-shaped valve with a bulge towards the lumen of the caecum - ileocecal valve, valva ileocecalis (valva ilealis).

AT submucosa, tela submucosa, the mesenteric part of the small intestine are located solitary lymphatic follicles, folliculi lymphatici solitarii reaching the surface of the mucous membrane; their size is equal to a millet grain, the number reaches 200. In addition, lymphatic follicles collected in groups lie in this section of the small intestine - group lymphatic follicles, folliculi lymphatici aggregati(see fig. 506). They are located on the edge opposite to the mesentery, have a length of 2-10 cm, a width of 1-3 cm; their number in the small intestine reaches 30-40.

Topography of the mesenteric part of the small intestine

The mesenteric part of the small intestine occupies a central position in the lower floor of the abdominal cavity, located below the mesentery of the transverse colon. On the right, top and left, the loops of the small intestine are bordered by the ascending (right), transverse (top), descending (left) colon. In front, the loops of the small intestine are covered, like an apron, with a greater omentum descending from the greater curvature of the stomach and the lower edge of the transverse colon and separating them from the anterior abdominal wall. The posterior surface of the small intestine is adjacent to the parietal peritoneum, covering, to the right of the root of the mesentery, the lower part of the duodenum, the head of the pancreas, the lower end of the right kidney, the right ureter, the right psoas major muscle, and to the left of the root of the mesentery, the lower end of the left kidney, the left ureter, the left large psoas muscle, abdominal aorta, inferior vena cava and common iliac vessels. To the left and below, the sigmoid colon with its mesentery adjoins the loops of the small intestine.

In the cavity of the small pelvis, the loops of the small intestine adjoin in front - to the bladder, behind - to the rectum, and in women - to the uterus and its appendages.

The terminal ileum crosses the right psoas major muscle and the right common iliac vessels.

Innervation: duodenum - plexus gastrici, hepaticus, mesentericus superior and branches n. vagus; mesenteric part of the small intestine - plexus coeliacus, mesentericus superior. In the thickness of the intestinal wall there is an extensive intestinal plexus (plexus entericus), associated with plexus mesentericus superior, it combines: plexus submucosus, plexus myentericus (between the circular and longitudinal muscle layers), plexus subserosus.

Blood supply: duodenum - aa. pancreatoduodenales superior, anterior et posterior (from a. gastroduodenalis) and a. pancreatoduodenalis inferior (from A. mesenterica superior); mesenteric part - aa. intestinales (from a. mesenterica superior). Venous blood through the veins of the same name is sent to v. portae. Lymphatic vessels carry lymph to nodi lymphatici pancreatoduodenales superiores, colici (from the duodenum), mesenterici, ileocolici.

The small intestine and ileum are combined under one term, since both sections are covered with peritoneum (specific tissue of the abdominal space) and are attached to the abdominal wall from behind with a special fold called the mesentery. Despite the absence of a common border, each section of the intestine has typical features. For example, the mesenteric part is attached to one of the edges of the small intestine, where the mesentery itself is attached. This process of the intestine is distinguished by a large diameter, thickened walls, and a large number of vascular plexuses.

The mesenteric part of the small intestine.

What is the mesenteric portion of the small intestine?

Under the mesentery in the intestines, it is customary to understand a special transverse section of the colon, tightly adjacent to the peritoneum at the back. On the mesenteric process in the intestines are attached in the retroperitoneal space:

transverse colon with large intestine - in the upper part of the process;
small intestine - in the middle part;
the rhizome of the mesentery ends at the sacrum.

Protection of the mesenteric parts is carried out on each side by the connective tissues of the peritoneum. A large number of nerves, lymphatic vessels, arteries with veins pass through this department, through which the small, ascending, transverse, descending colon and appendix are supplied with nerve impulses, blood.

The main functions of the mesenteric process are blood supply and innervation of most organs in the abdominal space. Therefore, the mesenteric parts are often involved in pathological processes, such as:

inflammation of the mesenteric process;
cyst formation;
tumorigenesis of the intestine.

Location of the mesentery

The root of the mesentery of the small intestine is fixed at the posterior peritoneal wall. This section begins to the left of the second lumbar vertebra. The median part is slightly inclined, moving from top to bottom, from the left side to the right. The end point is the transition point to the large intestine.

The mesenteric part reaches a height of 200 ml. The distance of the top point from the navel is 80-100 mm above the navel. From the inguinal zone, the lower part rises by 100 mm. The length of the root is 230 mm.

The intestines with the mesenteric process are the most vulnerable places in the body, since they are practically not protected from the inside and outside. The mesentery is slightly covered by the intestine, but this does not protect it from various pathologies.

Diseases of the mesenteric process of the small intestine

Under the influence of various factors, pathologies develop that lead to serious consequences affecting the mesenteric intestine.

Thrombosis with embolism is one of the diseases of the digestive system.

Thrombosis with embolism are diseases of the digestive system. The formation of an embolus occurs in the vessel of any other organ. Then it goes to the intestines along with the blood flow. Since the vessels of the intestines are rather thin, the embolus cannot pass further. For this reason, blockage occurs, neoplasms are formed, which lead to the necrosis of intestinal loops. Cause pathology can:

endocarditis, defects, general insufficiency and other heart diseases;
varicose veins;
atherosclerosis, phlebitis, aneurysm affecting the blood vessels;
hypertension;
myocardial infarction;
operations that increase thrombosis, for example, caesarean section, gastroenterostomy, splenectomy.

The degree and severity of the pathology depend on the location of the blockage and the type of mesenteric vessel damaged. When thrombosis forms in the upper part, parts of the intestine that are thin are affected. With a timely response in the intestine, rapid normalization of functions is possible. The disease is more common in older people. With untimely relief, a fatal outcome is possible. Symptoms: severe pain in the abdomen, weakening of the pulse, weakness, vomiting, bloating, diarrhea with blood in the stool.

It is difficult to diagnose the disease due to the similarity of the clinical picture with other diseases, for example, with appendicitis, peptic ulcer, cholecystitis. If detected, emergency assistance is required with excision of the dead intestinal loop with the removal of a blood clot.

The rupture of the mesentery is characterized by scale. The phenomenon is accompanied by damage to the integrity of other abdominal organs, in particular, the intestines. In this way, the mesenteric part of the small intestine is injured with closed or open internal mechanical damage. Pathology is accompanied by vascular defects, severe bleeding, followed by necrosis of the damaged part with nearby tissues. Isolated breaks are difficult to diagnose. Treatment of pathology is surgical and consists of ligation of vessels, removal of blood from the abdominal cavity. With a strong weakening of the body, a blood transfusion is performed

Cysts in the mesentery occur for various reasons, they can be of any size. Cysts are:

mesothelial;
intestinal;
lymphatic;
mixed;
false.

Some of the neoplasms can be palpated in the umbilical region. When diagnosing by fluoroscopy and pyelography, the entire mesenteric part of the small intestine and the intestine itself are clearly visible, which helps to identify the early stages of the disease. The complexity of the treatment lies in the need to remove the entire mesenteric vessel or part of the intestine when removing the cyst due to the presence of large vascular plexuses in the organ. Complications often occur:

low patency, rupture, intestinal volvulus;
suppuration of the cyst with the risk of rupture;
internal bleeding.

The risk of arterial embolism or vein thrombosis with cyst formation is high due to impaired blood circulation in the mesentery. Blood clots form in the vessels. They slow down blood flow throughout the intestines.

Tumor formations in the mesenteric process.

As the tumors grow, one of the signs may appear - anorexia.

They can be malignant sarcoma or cancer, benign fibroma or fibrolipoma. Their growth is not limited in size. Tumors are easily palpable in the middle part or on the right side of the abdomen. There may be no symptoms. As they grow, they appear: