Abdominal cavity of the body. Abdominal cavity, peritoneum and peritoneal cavity. What goes into the abdominal cavity?

The abdominal cavity is the largest cavity in the human body. It is surrounded by intra-abdominal and intra-pelvic fascia, covering the following anatomical formations from the inside: at the top - the diaphragm, at the front and on both sides - the muscles of the abdominal wall, at the back - the lumbar vertebrae, the quadratus lumborum and iliopsoas muscles, at the bottom - the pelvic diaphragm.

In the abdominal cavity there is the peritoneal cavity (cavitas peritonei) - a slit-like space between the layers of the parietal (peritoneum parietale) and visceral (peritoneum viscerale) peritoneum, containing a small amount of serous fluid. It should be noted that in practical surgery the concept of “abdominal cavity” is often used instead of “peritoneal”. At the initial stages of development, the organs of the abdominal cavity are located next to the peritoneal sac and, gradually rotating, are immersed into it. The leaf of the parietal peritoneum lines the walls of the abdominal cavity, and the leaf of the visceral peritoneum covers the organs: some on all sides (the so-called intraperitoneal arrangement of organs), others on only three (mesoperitoneal), some on only one side (retroperitoneal). If the organs are not covered with a layer of visceral peritoneum, we are talking about their extraperitoneal location.

The following organs or parts of the abdominal organs are located intraperitoneally: stomach, jejunum, ileum, transverse colon, sigmoid colon, as well as the cecum with the appendix, the upper part of the duodenum, and the fallopian tubes.

Mesoperitoneally located are the liver, gallbladder, descending duodenum, ascending colon and descending colon, middle third of the rectum, uterus and bladder. The pancreas is covered by peritoneum only in front and occupies a retroperitoneal position. The prostate gland, the horizontal part of the duodenum and the lower third of the rectum, kidneys, adrenal glands and ureters are located extraperitoneally.

Floors of the abdominal cavity

The abdominal cavity is divided into two floors: upper and lower. Between them pass the transverse colon with mesentery (mesocolon transversum) or the line of fixation of the mesentery of the transverse colon to the posterior wall of the abdomen.

The upper floor of the abdominal cavity contains the liver, gallbladder, stomach, spleen, upper part of the duodenum and most of the pancreas. In addition, there are vital relatively limited spaces, or bags, connected to each other using narrow slots. These include the omental, hepatic and pregastric bursae.

The omental bursa (bursa omentalis), which looks like a slit, is located behind the stomach and lesser omentum. The omental bursa contains the anterior, posterior, inferior and left walls.

The anterior wall of the bursa consists of the lesser omentum (omentum minus), the posterior wall of the stomach and the gastrocolic ligament, which begins the part of the greater omentum located between the stomach and the transverse colon. Sometimes (if it is clearly visible) the gastrosplenic ligament is visible in the anterior wall of the omental bursa.

The lesser omentum is a duplication of the peritoneum, starting from the porta hepatis and ending in the lesser curvature of the stomach and the adjacent part of the duodenum. The omentum is divided into the hepatoduodenal, hepatogastric and gastrophrenic ligaments.

The posterior wall of the omental bursa is the parietal peritoneum, behind which are the pancreas, the upper part of the duodenum, the left kidney, the left adrenal gland, the inferior vena cava, the abdominal aorta and the abdominal trunk. On top of the bursa is the caudate lobe of the liver and part of the diaphragm, and on the left side are the spleen and gastrosplenic ligament (lig. gastrolienale).

The lower wall of the omental bursa is formed by the transverse colon and its mesentery.

Through the cavity of the said bursa in the radial direction (back to front) from the pancreas, two ligaments pass in the form of the letter “V”: gastropancreatic (lig. gastropancreaticum) and pyloropancreaticum (lig. pyloropancreaticum), separating the vestibule of the omental bursa from its cavity itself. The gastropancreatic ligament contains the left gastric artery. The cavity of the omental bursa is connected to the upper floor of the peritoneal cavity by the omental opening (foramen epiploicum), which represents the right wall of the bursa cavity. The width of the omental opening is 3-4 cm, and, if there are no adhesions, 1-2 fingers fit into it. Injuries to its anterior and posterior walls are especially dangerous, since in the thickness of the hepatoduodenal ligament there are large vessels, nerves and bile ducts, and at the back - the inferior vena cava.

In addition, the omental bursa has a vestibule (vestibulum bursae omentalis), bounded above by the caudate lobe of the liver, below by the duodenum, and behind by the parietal peritoneum, which covers the inferior vena cava. This bag has an upper gland pocket (recess). Being in pre-

The omental bursa can be accessed by cutting the lesser omentum or gastrocolic ligament (the most commonly used method) or the mesentery of the transverse meningeal colon, as well as through the omental foramen.

The hepatic bursa is located between the right lobe of the liver and the diaphragm. Above and in front of it is the diaphragm, below is the superoposterior surface of the right lobe of the liver, behind is the right part of the coronary ligament of the liver (lig. coronarium), on the left is the falciform ligament dig. falciforme). The part of the hepatic bursa between the posterior surface of the right lobe of the liver, the diaphragm and the coronary ligament is called the right subphrenic (suprahepatic) space. Inferiorly it passes into the right lateral cable of the lower floor of the abdominal cavity.

Within the right subdiaphragmatic space, subdiaphragmatic ulcers can form as a complication of purulent cholecystitis, perforated gastric and duodenal ulcers.

As a result of injury to hollow organs, perforated stomach ulcers and other pathological conditions, air penetrates into the abdominal cavity, which, when the body is in an upright position, accumulates in the hepatic bursa. It can be detected during fluoroscopy.

The pregastric bursa (bursa pregastrica) is located in front of the stomach, and on top are the diaphragm and the left lobe of the liver, behind - the lesser omentum and the anterior wall of the stomach, in front - the anterior wall of the abdomen. On the right, the pregastric bursa is separated from the hepatic bursa by the falciform ligament and round ligament of the liver, and on the left it does not have a pronounced border.

Between the upper surface of the left lobe of the liver and the lower surface of the diaphragm, a gap is formed, or the left subphrenic space, delimited from the left lateral canal of the lower floor of the abdominal cavity by the permanent diaphragmatic-colic ligament.

The lower floor of the abdominal cavity is the space between the mesentery of the transverse colon and the pelvic cavity. The ascending colon and descending colon and the root of the mesentery of the small intestine divide it into 4 sections: the right and left lateral canals and the right and left mesenteric sinuses.

The right lateral canal is located between the right lateral abdominal wall and the ascending colon. At the top it reaches the right subdiaphragmatic space, at the bottom it continues into the right iliac fossa and into the small pelvis, since the right diaphragmatic-colic ligament is weakly expressed and sometimes completely absent. During the movement of the diaphragm, a suction action occurs in the hepatic bursa, so the infection in the right lateral canal spreads from bottom to top, into the right subdiaphragmatic space.

The left lateral canal passes between the descending colon and the left lateral abdominal wall. At the top it is covered by a well-defined and permanent left diaphragmatic-colic ligament, and at the bottom it passes into the left iliac fossa and the small pelvis.

The right mesenteric sinus (sinus mesentericus dexter) has the shape of a right triangle with the base directed upward. The boundaries of the sinus are: above - the transverse colon with mesentery, on the left and below - the mesentery of the small intestine, on the right - the ascending colon. In front, the mesenteric sinus is surrounded by the greater omentum. This anatomical formation is filled with loops of the small intestine.

The left mesenteric sinus (sinus mesentericus sinister) also has the shape of a right triangle, but with the base directed downward. It is larger in size than the right mesenteric sinus. The boundaries of this anatomical formation are: at the top - a small area of the transverse colon, on the left - the descending colon, on the right - the mesentery of the small intestine. In front, the left mesenteric sinus is covered with a greater omentum; from below it is open and passes directly into the pelvic cavity. This sinus is filled with loops of the small intestine. When the body is in an upright position, the upper sections of the sinuses are the deepest.

The mesenteric sinuses are connected through a gap between the mesentery of the transverse colon and the duodenojejunal flexure (flexura duodenojejunalis).

In places where the peritoneum passes from the walls of the abdominal cavity to the organs or from one organ to another, abdominal pockets are formed.

The upper and lower duodenal recess (recessus duodenalis superior et inferior) are located at the junction of the duodenum and the jejunum. Their depth varies within centimeters, but sometimes can increase sharply, as a result of which the depressions turn into a pocket located towards the retroperitoneal space. Thus, a hernial sac is formed into which loops of the small intestine can enter - a true internal hernia, or Treitz hernia.

The superior and inferior ileocecal pouches form where the ileum meets the cecum. In this case, the upper one is located between the upper edge of the terminal part of the ileum and the inner surface of the ascending colon, and the lower one is between the lower surface of the terminal part of the ileum and the wall of the cecum.

The postcolic recess (recessus retrocaecalis) in the form of a depression in the parietal peritoneum on the posterior wall of the abdomen is located behind the cecum.

The intersigmoid recess (recessus intersigmoideus) is a funnel-shaped or cylindrical formation with a round or oval inlet.

It is surrounded in front by the mesentery of the sigmoid colon, and behind by the parietal peritoneum, opening slightly into the left lateral canal of the peritoneal cavity. In the intersigmoid recess, as in those described above, an internal hernia can form.

The abdominal cavity contains a small amount of fluid (30 cc), which moistens the surface of the internal organs, making them easily move inside the cavity.

The article was prepared and edited by: surgeon

Knowledge of the structural features and location of the abdominal organs is important for understanding many pathological processes. The abdominal cavity contains the digestive and excretory organs. must be described taking into account the relative position of these organs.

General information

Abdomen - the space between the sternum and pelvis

The abdomen refers to the space of the body between the chest and pelvis. The basis of the internal structure of the abdomen is the abdominal cavity, which contains the digestive and excretory organs.

Anatomically, the area is limited by the diaphragm, located between the thoracic and abdominal cavities. The pelvic region begins at the level of the pelvic bones.

The structural features of the abdomen and abdominal cavity determine many pathological processes. The digestive organs are held together by special connective tissue, the mesentery.

This tissue has its own characteristics of blood supply. The abdominal cavity also contains organs of other important systems - kidneys and.

Many large blood vessels supply the tissues and organs of the abdominal cavity. In this anatomical region, the aorta and its branches, the inferior genital vein and other large arteries and veins are distinguished.

The organs and main vessels of the abdominal cavity are protected by muscular layers that form the external structure of the abdomen.

External structure and abdominal muscles

Structure of the abdomen: internal organs

The external structure of the abdomen is no different from the structure of other anatomical regions of the body. The most superficial layers include the skin and subcutaneous fat.

The subcutaneous fat layer of the abdomen can be developed to varying degrees in people with different constitutional types. The skin, fat and subcutaneous fascia contain a large number of arteries, veins and nerve structures.

The next layer of the abdomen contains the muscles. The abdominal area has a fairly powerful muscle structure that allows it to protect the abdominal organs from external physical influence.

The abdominal wall consists of several paired muscles, the fibers of which are intertwined in different places. Main abdominal muscles:

External oblique muscle. This is the largest and most superficial paired abdominal muscle. It originates from the eight lower ribs. Fibers of the external oblique muscle are involved in the formation of a dense aponeurosis of the abdomen and inguinal canal, which contains the structures of the reproductive system.
Internal oblique muscle. This is the structure of the intermediate layer of paired abdominal muscles. The muscle originates from the iliac crest and part of the inguinal ligament. Individual fibers are also associated with the ribs and pubic bones. Like the external muscle, the internal oblique muscle is involved in the formation of the wide abdominal aponeurosis.
Transverse abdominis muscle. This is the deepest muscle of the superficial layer of the abdomen. Its fibers are connected to the ribs, iliac crest, inguinal ligament, fascia of the chest and pelvis. The structure also forms the aponeurosis and inguinal canal.
Rectus abdominis muscle. It is a long muscle associated with the ribs, sternum and pubic bone. It is this muscle layer that forms the so-called abdominal press, which is clearly visible in physically developed people. The functions of the rectus abdominis muscle are associated with flexion of the body, obstetric processes, defecation, urination and forced exhalation.
Pyramidal muscle. It is a triangular muscle structure located in front of the lower part of the rectus abdominis muscle. The fibers of the pyramidalis muscle are connected to the pubic bones and the linea alba. The muscle may be absent in 20% of people, which is due to the individual characteristics of the abdominal structure.
The aponeuroses and muscle lines of the abdomen are of particular importance in protecting and maintaining the shape of the abdominal structures. In addition, the abdominal muscles form the inguinal canal, which contains the spermatic cord in men and the round ligament of the uterus in women.

Abdomen

Abdominal structure: muscles

The internal structure of the abdomen is represented by the abdominal cavity. The cavity is lined from the inside by peritoneum, which has internal and external layers.

Between the layers of the peritoneum are the abdominal organs, blood vessels and nerve formations. In addition, the space between the layers of the peritoneum contains a special liquid that prevents friction.

The peritoneum not only nourishes and protects the structures of the abdomen, but also anchors the organs. The peritoneum also forms what is called mesenteric tissue, which is connected to the abdominal wall and abdominal organs.

The boundaries of the mesenteric tissue extend from the pancreas and small intestine to the lower parts of the colon. The mesentery secures organs in a certain position and nourishes tissues with the help of blood vessels.

Some abdominal organs are located directly in the abdominal cavity, others in the retroperitoneal space. Such features are determined by the position of the organs relative to the layers of the peritoneum.

Abdominal organs

Abdomen

The organs located in the abdominal cavity belong to the digestive, excretory, immune and hematopoietic systems.

Their mutual arrangement ensures the performance of many joint functions.

Main organs of the abdomen:

Liver. The organ is located in the right abdomen directly below the diaphragm. The functions of this organ are related to the processes of digestion, detoxification and metabolism. All nutritional components formed as a result of digestion enter the liver cells along with the blood, where chemical compounds harmful to the body are neutralized. The liver is also involved in the formation of bile, which is necessary for the digestion of fats.
Stomach. The organ is located in the left abdomen under the diaphragm. This is an extended part of the digestive tract, connected to the esophagus and the initial part of the small intestine. The key processes of chemical decomposition of food substrates occur in the stomach. In addition, stomach cells help absorb vitamin B12, which is necessary for the functioning of body cells. Hydrochloric acid contained in the stomach helps destroy bacteria.
Gallbladder. The organ is located under the liver. The gallbladder is a storage facility for bile. When food components enter the duodenum for digestion, the gallbladder secretes bile into the intestinal cavity.
Pancreas. This structure is located below the stomach between the spleen and duodenum. The pancreas is an indispensable digestive organ necessary for the final processes of food digestion. The gland produces enzymes that make it possible to convert large food components into the structural units necessary for cells. The role of the pancreas in glucose metabolism is also very important. The gland secretes insulin and glucagon, which control blood sugar.
Spleen. The organ is located in the left region of the abdomen next to the stomach and pancreas. It is an organ of hematopoiesis and immunity, allowing the deposition of blood components and the disposal of unnecessary cells.
Small and large intestines. The main processes of digestion and assimilation of food substrates occur in the sections of the small intestine. The large intestine produces and deposits feces and also absorbs water.
Kidneys. These are paired excretory organs that filter the bloodstream and dispose of metabolic waste. The kidneys are connected to the ureters, bladder and urethra. In addition, the kidneys secrete a number of important substances necessary for the synthesis of vitamin D and the formation of red blood cells.

The close proximity of the abdominal organs determines the characteristics of many diseases. Inflammatory processes associated with the entry of bacteria into the abdominal cavity can be deadly.

Methods for examining abdominal organs

Intestines: human anatomy

Numerous diagnostic methods allow you to assess the condition of the abdominal organs and, if necessary, confirm the presence of the disease.

Doctors begin with a physical examination of the patient, which allows them to detect external manifestations of pathologies. The next stage of diagnosis is the appointment of instrumental research methods.

Methods for examining the abdominal organs:

Esophagogastroduodenoscopy. A flexible tube equipped with a camera is inserted through the mouth into the patient's digestive tract. The device allows you to assess the condition of the esophagus, stomach and duodenum.
Colonoscopy. In this case, the tube is inserted into the lower digestive tract through the anus. The procedure allows you to examine the rectum and colon.
X-ray and computed tomography. The methods allow you to take pictures of the abdominal cavity.
Magnetic resonance imaging. This highly accurate method is often used for detailed examination of the liver, pancreas and gallbladder.
Ultrasound diagnostics. Using the procedure, the general condition of the abdominal organs is assessed.

Specialized techniques, including biopsy and breath testing, may be used to diagnose specific diseases.

Thus, the structure of the abdomen is important not only from the point of view of anatomical features, but also from the point of view of diagnosing diseases.

The following video will introduce you to the anatomy of the human abdominal cavity:

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The abdominal cavity (or abdominal cavity) is the largest cavity in the human body. It contains the digestive and urinary organs, and the adrenal glands. The abdominal cavity is limited from above by the diaphragm, below it continues into the pelvic cavity, in front and on the sides it is limited by the abdominal muscles, and behind by the lumbar muscles and the corresponding part of the spinal column. The aorta, inferior vena cava, nerve plexuses, lymphatic vessels and nodes lie on the posterior wall of the cavity. The inner surface of the abdominal cavity is lined with retroperitoneal fascia, fatty tissue and parietal peritoneum.

The peritoneum (peritoneum) is a serous membrane that lines the abdominal cavity and covers the internal organs located in it. The peritoneum is formed by a serous plate and covered with single-layer squamous epithelium. The peritoneum that lines the internal organs is called visceral, and the peritoneum that lines the walls of the abdominal cavity is called parietal. Connecting, the visceral and parietal peritoneum forms a limited closed peritoneal cavity. In an adult, the total area of the visceral and parietal peritoneum is about 1.7 m2. The peritoneal cavity contains a small amount of serous fluid, which reduces friction between the surfaces of the internal organs covered by the peritoneum.

The peritoneum, passing from the walls of the abdominal cavity to organs or from organ to organ, forms ligaments, mesenteries, folds and pits. The peritoneum covers the internal organs unequally. A number of organs are covered by peritoneum on only one side (kidneys, adrenal glands, pancreas, part of the duodenum). This arrangement of organs is called extraperitoneal, and the organs themselves are called retroperitoneal.

Organs covered by peritoneum on three sides (ascending colon, descending colon, middle part of the rectum, bladder) have a mesoperitoneal location. If the organs are covered with peritoneum on all sides, then they are located intraperitoneally, or intraperitoneally (stomach, small and cecum, appendix, transverse colon, sigmoid colon, upper part of the rectum, spleen, liver, fallopian tubes and uterus).

The abdominal cavity is conventionally divided into three floors: upper, middle and lower. The upper floor is limited at the top by a diaphragm; on the side - the lateral walls of the abdominal cavity, covered with the parietal peritoneum; below - the transverse colon and its mesentery. The stomach, liver, spleen, pancreas and upper part of the duodenum are located here. Connecting with the anterior and posterior walls of the abdomen, the peritoneum passes to the diaphragm, and then to the liver and forms the coronary, falciform, right and left triangular ligaments of the liver. At the porta hepatis, the posterior and anterior layers of the peritoneum are connected and pass to the stomach and duodenum in the form of the hepatogastric and hepatoduodenal ligaments. These ligaments are located between the porta hepatis, the lesser curvature of the stomach and the upper part of the duodenum and form the lesser omentum. The latter contains the hepatic artery, common bile duct and portal vein.

The greater omentum is a long fold of peritoneum that hangs in front of the transverse colon and loops of the small intestine like an apron. It consists of four layers of peritoneum, between which there is fatty tissue.

The middle floor of the abdominal cavity is limited by the mesentery of the transverse colon and the entrance to the pelvis. It contains the small intestine and part of the large intestine, as well as many pits and depressions that are formed by folds of the peritoneum and internal organs. More permanent are the pits around the jejunum (superior and inferior duodenal recesses), the terminal part of the ileum (superior and inferior ileocecal recesses), the cecum (posteriorly - the cecal recess) and in the mesentery of the sigmoid colon (intersigmoid recess).

The lower floor of the abdominal cavity is located in the pelvis. It contains the rectum, bladder, seminal vesicles (in men), uterus with fallopian tubes and ovaries (in women). The peritoneum in the lower surface covers not only the upper and part of the middle section of the rectum, but also the organs of the genitourinary apparatus.

In men, the peritoneum from the rectum passes to the seminal vesicles and the posterior wall of the bladder and forms the rectovesical cavity. In women, the peritoneum passes from the rectum to the vagina and posterior wall of the uterus, first forming the rectouterine cavity and then the vesicouterine cavity.

Abdomen, cavitas abdominalis , is a space bounded above by the diaphragm, in front and on the sides by the anterior abdominal wall, behind by the spinal column and back muscles, and below by the perineal diaphragm. The abdominal cavity contains the organs of the digestive and genitourinary systems. The walls of the abdominal cavity and the internal organs located in it are covered with a serous membrane - peritoneum, peritoneum . The peritoneum is divided into two layers: parietal, peritone u m parietale , covering the walls of the abdominal cavity, and visceral, peritoneum visceral e , covering the abdominal organs.

Peritoneal cavity, cavitas peritonei , is a space bounded by two visceral layers or visceral and parietal layers of the peritoneum, containing a minimal amount of serous fluid.

The relationship of the peritoneum to the internal organs is different. Some organs are covered by peritoneum on only one side, i.e. located extraperitoneally (pancreas, duodenum, kidneys, adrenal glands, ureters, unfilled bladder and lower part of the rectum). Organs such as the liver, descending and ascending colons, the full bladder and the middle part of the rectum are covered by peritoneum on three sides, i.e. occupy a mesoperitoneal position. The third group of organs is covered with peritoneum on all sides and these organs (stomach, mesenteric part of the small intestine, transverse and sigmoid colons, cecum with appendix, upper part of the rectum and uterus) occupy an intraperitoneal position.

The parietal peritoneum covers the inside of the anterior and lateral walls of the abdomen and then continues to the diaphragm and the posterior abdominal wall. Here the parietal peritoneum passes into the visceral peritoneum. The transition of the peritoneum to the organ occurs either in the form ligaments, ligamentum , or in the form mesentery, mesenterium , mesocolon . The mesentery consists of two layers of peritoneum, between which there are vessels, nerves, lymph nodes and fatty tissue.

The parietal peritoneum on the inner surface forms five folds:

median umbilical fold, plica umbilicale mediana, unpaired fold, runs from the apex of the bladder to the navel, contains the median umbilical ligament - overgrown embryonic urinary duct, urachus ;

medial umbilical fold , plica umbilicalis medialis , paired fold - runs on the sides of the median fold, contains the medial umbilical ligament - an overgrown umbilical artery of the fetus;

lateral umbilical fold, plica umbilicalis lateralis , also steam room - contains the inferior epigastric artery. The umbilical folds limit the pits related to the inguinal canal.

The parietal peritoneum passes to the liver in the form of liver ligaments.

The visceral peritoneum passes from the liver to the stomach and duodenum in the form of two ligaments: hepatogastric, lig. hepatogastrium , And hepatoduodenal, lig. hepatoduodenal . The latter contains the common bile duct, portal vein and proper hepatic artery.

The hepatogastric and hepatoduodenal ligaments make up small seal, omentum minus .

Big seal, omentum majus , consists of four layers of peritoneum, between which there are vessels, nerves and fatty tissue. The greater omentum begins with two layers of peritoneum from the greater curvature of the stomach, which descend down in front of the small intestine, then rise up and attach to the transverse colon.

The peritoneal cavity is divided into three floors: upper, middle and lower:

the upper floor is bounded above by the diaphragm, below by the mesentery of the transverse colon. In the upper floor there are three bags: hepatic, pregastric and omental. Hepatic bursa, bursa hepatica , separated from pregastric bursa, bursa pregastrica , falciform ligament. The hepatic bursa is limited by the diaphragm and the right lobe of the liver, the pregastric bursa is located between the diaphragm and the diaphragmatic surface of the left lobe of the liver and between the visceral surface of the left lobe of the liver and the stomach. Omental bag, bursa omentalis , is located behind the stomach and lesser omentum and communicates with the peritoneal cavity through gland hole, foramen epiploicum . In children, the omental bursa communicates with the cavity of the greater omentum; in adults this cavity does not exist, since the four layers of the peritoneum grow together;

The middle floor of the peritoneal cavity is located between the mesentery of the transverse colon and the entrance to the pelvis. The middle floor is divided by the root of the mesentery of the small intestine, which runs from the left side of the XI lumbar vertebra to the right sacroiliac joint at right and left mesenteric sinuses, sinus mesentericus dex. et sin . Between the ascending colon and the lateral wall of the abdominal cavity - left lateral channel, canalis lateralis sin ;

The parietal peritoneum forms several depressions (pockets), which are the site of formation of retroperitoneal hernias. During the transition of the duodenum to the jejunum, superior and inferior duodenal recesses, recessus duodenalis sup . et inf . During the transition of the small intestine to the large intestine there are superior and inferior iliocecal pouches, recessus ileocecalis sup. et inf . Behind the cecum is retrocecal fossa, recessus retrocecalis . On the lower surface of the mesentery of the sigmoid colon there is intersigmoid recess, recessus intersigmoideus;

The lower floor of the peritoneal cavity is located in the pelvis. The peritoneum covers its walls and organs. In men, the peritoneum passes from the rectum to the bladder, forming rectovesical recess, excavatio rectovesicalis . In women, there is a uterus between the rectum and the bladder, so the peritoneum forms two depressions: a) rectal-uterine, excavatio rectouterina , – between the rectum and uterus; b) vesicouterine, excavatio vesicouterina , – between the bladder and the uterus.

Age characteristics. Peritoneum of a newborn thin, transparent. Blood vessels and lymph nodes are visible through it, since the subperitoneal fatty tissue is poorly developed. The greater omentum is very short and thin. The newborn has depressions, folds and pits formed by the peritoneum, but they are weakly expressed.

The abdominal cavity is limited in front and on the sides by the abdominal walls, behind by the lumbar region, and above by the diaphragm; from below it passes into the pelvic cavity. It contains the abdominal cavity and abdominal organs.

Abdomen(cavum peritoneale) is represented by a space surrounded by a serous membrane - the peritoneum (peritoneum). It includes all organs covered by the peritoneum (Fig. 133). The serous layer covering the walls of the abdomen from the inside is called parietal, or parietal, and the layer adjacent to the organs is called splanchnic, or visceral. Both sheets are one whole; they directly transform into one another. Between the layers of the peritoneum there is a small amount of serous fluid - up to 30 ml.

Rice. 133. Sinuses and canals of the abdominal cavity.
I - hepatic bursa; II - pregastric bursa; III - right mesenteric sinus; IV - left mesenteric sinus; V - right channel; VI - left channel, 1 - diaphragm; 2 - coronary ligament of the liver; 3 - liver; 4 - stomach; 5 - spleen; 6 - transverse colon: 7 - duodenal-small intestinal bend; 8 - descending colon: 9 - sigmoid colon; 10 - bladder; 11 - terminal ileum; 12 - cecum with vermiform appendix; 13 - root of the mesentery of the small intestine; 14 - ascending colon; 15 - duodenum; 16 - gallbladder.

Most organs (stomach, small intestine, cecum, transverse colon and sigmoid colon, spleen) are enveloped by the peritoneum on all sides, i.e. they lie intraperitoneally, or intraperitoneally. They are supported by the mesentery or ligaments formed by the layers of the peritoneum. Other organs (liver, gall bladder, ascending and descending colon, part of the duodenum, pancreas, rectum) are covered by the peritoneum on three sides, with the exception of the posterior one, i.e. they are located mesoperitoneally. A small number of organs (duodenum, pancreas, kidneys, ureters, large blood vessels) lie behind the peritoneum - they occupy a retroperitoneal position.

Using the position of the transverse colon with its mesentery, the abdominal cavity is divided into upper and lower floors, which approximately corresponds to the plane passing through the ends of the X ribs. In the upper floor there are three sacs (or bursae): hepatic, pregastric and omental. The hepatic bursa (bursa hepatica) is located between the diaphragm, the anterior wall of the abdomen and the right lobe of the liver. The pregastric bursa (bursa pregastrica) is located in front of the stomach with its ligaments and is adjacent to the left lobe of the liver and spleen. These bags are separated from each other by the falciform ligament of the liver. The omental bursa (bursa omentalis) is represented by a slit-like space limited in front by the stomach with its ligaments, below by the left part of the transverse colon with its mesentery, on the left by the spleen with its ligaments and behind by the peritoneum of the posterior abdominal wall covering the pancreas, left kidney with the adrenal glands, aorta and inferior vena cava; on top, the omental bursa adjoins the caudate lobe of the liver (Fig. 134). This bag communicates with the common cavity through the omental foramen of Winslowi (for. epiploicum Winslowi), bounded by the peritoneum-covered right kidney with the adjacent inferior vena cava behind, the initial part of the duodenum below, the caudate lobe of the liver above and the hepatoduodenal ligament in front.

Rice. 134. The course of the peritoneum on a sagittal section of the abdomen (semi-schematic). The abdominal aorta is slightly displaced to the right and left undissected. 1 - diaphragm; 2 - small oil seal; 3 - gland hole; 4 - truncus coeliacus; 5 - a. mesenterica superior; 6 - pancreas; 7 - a. renalis; 8 - cisterna chyli and a. testicularis; 9 - duodenum; 10 - a. mesenterica inf.; 11 - latero- and retroaortic lymph nodes; 12 - mesenterium; 13 - vasa iliaca communia; 14 - greater omentum: 15 - colon transversum; 16 - mesocolon transversum; 17 - stomach; 18 - liver.

In the lower floor of the abdominal cavity, the right and left mesenteric sinuses and lateral canals are distinguished. The right sinus (sinus mesentericus dexter) is bounded above by the mesentery of the transverse colon, on the right by the ascending colon, on the left and below by the mesentery of the small intestine and in front by the greater omentum. The inflammatory processes occurring here are to a certain extent confined within the sinus. The left mesenteric sinus (sinus mesentericus sinister) is bounded above by the mesentery of the transverse colon, on the right by the mesentery of the small intestines, on the left by the descending colon and in front by the greater omentum. At the bottom, the sinus is open into the pelvic cavity, which makes it possible for pus or blood to spread here. Both mesenteric sinuses communicate through a gap limited by the initial part of the small intestine and the mesentery of the transverse colon. The right lateral canal (canalis lateralis dexter) is limited by the side wall of the abdomen and the ascending colon, the left (canalis lateralis dexter) is limited by the side wall of the abdomen and the descending colon. Both canals at the top communicate with the upper floor of the abdominal cavity, but on the left this communication is limited due to the existence of lig. phrenicocolicum. Inflammatory processes can spread through these channels.