![\"\"](\"https:\/\/meddists.com\/learn\/wp-content\/uploads\/2021\/11\/peritoneum.png\")
Description<\/h3>\n<\/span>\n\n\nThe peritoneum is divided into the visceral part<\/strong> (lines the viscera \u2014 organs) and a parietal part<\/strong> (facing body walls), forming the peritoneal cavity<\/strong> in between.<\/p>\n\n\n\n- In men, the peritoneum is completely sealed, while in women, the uterine tubes form openings in the peritoneum.<\/li>
- The visceral peritoneum is sensitive to stretching and chemical irritations.<\/li>
- The parietal peritoneum is sensitive to touch, heat and cold.<\/li>
- The peritoneum consists of squamous epithelium \u2014 mesothelium<\/strong>, made of mesothelial cells<\/strong>, and it develops from the mesoderm<\/strong> lining the body wall.<\/li><\/ul>\n\n\n<\/span>\n
Functions<\/h4>\n<\/span>\n\n\n- Compartmentalization<\/li>
- Protection \u2014 waterproof barrier<\/li>
- Lubrication to prevent friction and allow movement of organs<\/li>
- Fat storage<\/li><\/ol>\n\n\n<\/span>\n
Folds<\/h3>\n<\/span>\n\n\nPeritoneal folds are formed by multiple layers of the peritoneum. These folds are named according to the organ they come in contact with:<\/p>\n\n\n\n
- Omenta <\/strong>\u2014 Stomach<\/li>
- Mesentery<\/strong> \u2014 Small intestine<\/li>
- Mesocolon<\/strong> \u2014 Large intestine<\/li>
- Peritoneal folds that adhere organs to each other and to the abdominal wall are referred to as peritoneal ligaments.<\/strong><\/li><\/ul>\n\n\n<\/span>\n
Omenta<\/h4>\n<\/span>\n\n\nThe omenta (singular: omentum<\/em>) are folds of the peritoneum that attach and hang from organs surrounding the stomach:<\/p>\n\n\n\n- Greater omentum<\/strong>
- Four layers of peritoneum hanging from the greater curvature of the stomach<\/li><\/ul><\/li>
- Lesser omentum<\/strong>
- Two layers of peritoneum attaching the stomach to the liver<\/li>
- Made from the ventral mesogastrium<\/strong> \u2014 forming the hepatoduodenal<\/strong> and gastrohepatic ligaments.<\/strong><\/li><\/ul><\/li><\/ul>\n\n\n\n
![\"\"](\"https:\/\/meddists.com\/wp-content\/uploads\/2018\/10\/organs-omenta-600x462.png\")
<\/a>Figure 2. Abdominal organs and the omenta (the liver is lifter upwards)<\/strong><\/figcaption><\/figure>\n\n\n<\/span>\nMesentery<\/h4>\n<\/span>\n\n\nA fan or flower-shaped fold of peritoneum attaching parts of the intestine to the posterior abdominal wall; it forms from the posterior parietal peritoneum and consists of connective tissue and fat, and contains the superior mesenteric artery and vein. The mesentery divides the inframesocolic space into the right and left parts.<\/p>\n\n\n\n
The root of the mesentery <\/strong>is the point of origin of the mesentery: an oblique line formed between the duodenojejunal flexure on the left, to the ileocecal junction on the right iliac fossa. The position is oblique thanks to the 270\u00b0 rotation of the midgut during the development of the embryo.<\/p>\n\n\n\n![\"\"](\"https:\/\/meddists.com\/wp-content\/uploads\/2018\/08\/mesentery-600x338.jpg\")
<\/a>Figure 3. Mesentery<\/strong>\u00a0(Credit: scientificanimations.com,\u00a0CC BY-SA 4.0<\/a>)<\/figcaption><\/figure>\n\n\n<\/span>\nMesocolon<\/h4>\n<\/span>\n\n\nThe mesocolon is the collective name for the peritoneal folds that attach the large intestine to the posterior abdominal wall.<\/p>\n\n\n\n
- It allows movement to a certain degree and engulfs the neurovasculature associated with the large intestine.<\/li>
- The anterior layer of the transverse mesocolon adheres to the posterior layer of the greater omentum.<\/li>
- It can be divided based on the part of the intestine it is attached to:
- The mesoappendix<\/strong><\/li>
- Ascending mesocolon<\/strong><\/li>
- Transverse mesocolon<\/strong><\/li>
- Descending mesocolon<\/strong><\/li>
- Sigmoid mesocolon<\/strong><\/li>
- Mesorectum<\/strong><\/li>
- Note that the cecum has no separate mesocolon<\/li><\/ul><\/li><\/ul>\n\n\n\n
![\"\"](\"https:\/\/meddists.com\/wp-content\/uploads\/2020\/02\/mesocolon-600x516.png\")
<\/a>Figure 4. Mesocolon and mesentery<\/strong><\/figcaption><\/figure>\n\n\n<\/span>\nPeritoneal cavity<\/h3>\n<\/span>\n\n\nThe peritoneal cavity is a collapsed space containing only tiny amounts of serous fluid for lubrication.<\/p>\n\n\n\n
There are two approaches in dividing it:<\/p>\n\n\n\n
- The greater<\/strong> and lesser sacs<\/strong><\/li>
- The supracolic <\/strong>and infracolic compartments<\/strong><\/li><\/ul>\n\n\n<\/span>\n
Greater and lesser sacs<\/h4>\n<\/span>\n\n\n- The greater sac<\/strong>, as its name suggests, is the greater portion of the peritoneal cavity.
- Formed between the parietal and visceral peritoneum.<\/li>
- It starts from the inferior surface of the diaphragm, down to the floor of the abdominal cavity (above the pelvis).<\/li><\/ul><\/li>
- The lesser sac<\/strong>, or omental bursa<\/strong>, is the lesser portion of the peritoneal cavity.
- Located posterior to the stomach and liver.<\/li>
- Communicates with the greater sac via the omental<\/strong> foramen <\/strong>(or epiploic foramen of Winslow<\/strong>).
- The omental foramen is surrounded by the following structures:
- Superiorly<\/strong> \u2014 The liver<\/li>
- Inferiorly<\/strong> \u2014 The duodenum<\/li>
- Anteriorly <\/strong>\u2014 Hepatoduodenal ligament (containing the portal vein, hepatic artery proper, and bile duct)<\/li>
- Posteriorly<\/strong> \u2014 Inferior vena cava<\/li><\/ul><\/li><\/ul><\/li><\/ul><\/li><\/ul>\n\n\n\n
![\"\"](\"https:\/\/meddists.com\/wp-content\/uploads\/2018\/10\/greater_lesser_sacs.png\")
<\/a>Figure 5. A cross-section showing the sacs of the peritoneal cavity<\/strong>\u00a0(Credit: Dennis M DePace, PhD,\u00a0CC BY-SA 4.0<\/a>)<\/figcaption><\/figure>\n\n\n<\/span>\nSupracolic and infracolic compartments<\/h4>\n<\/span>\n\n\nThe transverse colon divides the peritoneal cavity into the supracolic<\/strong> and infracolic<\/strong> compartments.<\/p>\n\n\n\n- The supracolic compartment is located above the transverse colon.<\/li>
- The infracolic compartment is located below the transverse colon.<\/li><\/ul>\n\n\n<\/span>\n
Organs<\/h3>\n<\/span>\n\n\nOrgans completely covered by peritoneum are referred to as intra-peritoneal<\/strong>:<\/p>\n\n\n\n- These organs are covered immediately by a visceral layer of peritoneum, which is continuous with the abdominal wall dorsally (and ventrally in the foregut \u2014 stomach and liver), and allows the passage the nerves and vessels, through the mesentery<\/strong>
- Stomach<\/li>
- The first part of the duodenum<\/li>
- Small intestine<\/li>
- Transverse colon<\/li>
- Sigmoid colon<\/li>
- Liver<\/li>
- Spleen<\/li>
- The tail of the Pancreas<\/li>
- In women \u2014 The body of the uterus, the fallopian tubes, and the ovaries
- The ovaries are the only organ truly located within the peritoneal cavity, and the fallopian tubes form an opening to it (as mentioned above).<\/li>
- Oocytes released from the ovaries are initially located within the peritoneal cavity, before being swept into the uterine tubes through their opening by the fimbriae.<\/li><\/ul><\/li><\/ul><\/li><\/ul>\n\n\n\n
Those covered only partially are either retro-<\/strong> or infra-peritoneal<\/strong><\/p>\n\n\n\n- Retroperitoneal<\/strong> organs are located posterior to the peritoneum \u2014 hence, are only covered by peritoneum anteriorly
- The remainder of the duodenum<\/li>
- Cecum<\/li>
- Ascending colon<\/li>
- Descending colon<\/li>
- The majority of the pancreas<\/li>
- The kidneys.<\/li>
- View the retroperitoneum lesson<\/a> for more information<\/li><\/ul><\/li>
- Infraperitoneal<\/strong> organs are located below the peritoneum \u2014 hence, are only covered by peritoneum superiorly; these are the pelvic organs, discussed below.<\/li><\/ul>\n\n\n<\/span>\n
Peritoneal relations in the pelvis<\/h3>\n<\/span>\n\n<\/span>\nFemales<\/h4>\n<\/span>\n\n\n- Descends on the anterior abdominal wall, forming the supravesical fossa over the bladder, and the paravesical fossae to the sides of the bladder.<\/li>
- Reflects from the superior surface of the bladder onto the uterus forming the vesicouterine pouch.<\/li>
- Covers the body and fundus of the uterus and the posterior fornix of the vagina, extending laterally to blend with the broad ligament of the uterus.<\/li>
- The posterior reflection covers the rectum forming the rectouterine pouch (Douglas pouch), with the pararectal fossae to the sides of the rectum.<\/li><\/ol>\n\n\n\n
![\"\"](\"https:\/\/meddists.com\/wp-content\/uploads\/2020\/01\/peritoneum-600x445.png\")
<\/a>Figure 6. The peritoneal relations of the female pelvis (in blue)<\/strong>\u00a0(Credit: BruceBlaus,\u00a0CC BY-SA 4.0<\/a>)<\/figcaption><\/figure>\n\n\n<\/span>\nMales<\/h4>\n<\/span>\n\n\n- Descends on the anterior abdominal wall, forming the supravesical fossa over the bladder, and the paravesical fossae to the sides of the bladder.<\/li>
- Descends on the posterior surface of the bladder, covering the ureters, ductus deferens, and the superior edge of the seminal glands (a reflection known as the ureteric fold).<\/li>
- The posterior reflection covers the rectum forming the rectovesical pouch (Douglas pouch), with the pararectal fossae to the sides of the rectum.<\/li><\/ol>\n\n\n<\/span>\n
Embryology<\/h3>\n<\/span>\n\n\nDuring the development of the GIT and the associated tissues, the mesogastrium <\/strong>serves as an origin for the developing peritoneum, adhering the primitive gut to the body wall.<\/p>\n\n\n\nThe mesogastrium is divided into the ventral<\/strong> and dorsal<\/strong> portions:<\/p>\n\n\n\n- The ventral mesogastrium<\/strong> is present only at the region of the foregut:
- It extends from the lesser curvature to the septum transversum and the anterior abdominal wall.<\/li>
- It disappears almost completely, and gives rise to several structures related to the liver:
- Falciform ligament<\/li>
- Right and left triangular ligaments<\/li>
- Coronary ligaments<\/li>
- Lesser omentum<\/li><\/ul><\/li><\/ul><\/li>
- The dorsal mesogastrium<\/strong> is present throughout the GIT (foregut, midgut, and hindgut):
- It extends from the greater curvature of the stomach to the posterior abdominal wall.<\/li>
- It gives rise to:
- The greater omentum<\/li>
- Gastrosplenic ligament<\/li>
- Splenorenal ligament<\/li><\/ul><\/li><\/ul><\/li><\/ul>\n\n\n\n
![\"\"](\"https:\/\/meddists.com\/wp-content\/uploads\/2020\/02\/mesogastrium.png\")
<\/a>Figure 7. An illustration of the development of the GIT<\/strong><\/figcaption><\/figure>\n<\/span>
- In men, the peritoneum is completely sealed, while in women, the uterine tubes form openings in the peritoneum.<\/li>
- The visceral peritoneum is sensitive to stretching and chemical irritations.<\/li>
- The parietal peritoneum is sensitive to touch, heat and cold.<\/li>
- The peritoneum consists of squamous epithelium \u2014 mesothelium<\/strong>, made of mesothelial cells<\/strong>, and it develops from the mesoderm<\/strong> lining the body wall.<\/li><\/ul>\n\n\n<\/span>\n
Functions<\/h4>\n<\/span>\n\n\n
- Compartmentalization<\/li>
- Protection \u2014 waterproof barrier<\/li>
- Lubrication to prevent friction and allow movement of organs<\/li>
- Fat storage<\/li><\/ol>\n\n\n<\/span>\n
Folds<\/h3>\n<\/span>\n\n\n
Peritoneal folds are formed by multiple layers of the peritoneum. These folds are named according to the organ they come in contact with:<\/p>\n\n\n\n
- Omenta <\/strong>\u2014 Stomach<\/li>
- Mesentery<\/strong> \u2014 Small intestine<\/li>
- Mesocolon<\/strong> \u2014 Large intestine<\/li>
- Peritoneal folds that adhere organs to each other and to the abdominal wall are referred to as peritoneal ligaments.<\/strong><\/li><\/ul>\n\n\n<\/span>\n
Omenta<\/h4>\n<\/span>\n\n\n
The omenta (singular: omentum<\/em>) are folds of the peritoneum that attach and hang from organs surrounding the stomach:<\/p>\n\n\n\n
- Greater omentum<\/strong>
- Four layers of peritoneum hanging from the greater curvature of the stomach<\/li><\/ul><\/li>
- Lesser omentum<\/strong>
- Two layers of peritoneum attaching the stomach to the liver<\/li>
- Made from the ventral mesogastrium<\/strong> \u2014 forming the hepatoduodenal<\/strong> and gastrohepatic ligaments.<\/strong><\/li><\/ul><\/li><\/ul>\n\n\n\n<\/a>
Figure 2. Abdominal organs and the omenta (the liver is lifter upwards)<\/strong><\/figcaption><\/figure>\n\n\n<\/span>\n Mesentery<\/h4>\n<\/span>\n\n\n
A fan or flower-shaped fold of peritoneum attaching parts of the intestine to the posterior abdominal wall; it forms from the posterior parietal peritoneum and consists of connective tissue and fat, and contains the superior mesenteric artery and vein. The mesentery divides the inframesocolic space into the right and left parts.<\/p>\n\n\n\n
The root of the mesentery <\/strong>is the point of origin of the mesentery: an oblique line formed between the duodenojejunal flexure on the left, to the ileocecal junction on the right iliac fossa. The position is oblique thanks to the 270\u00b0 rotation of the midgut during the development of the embryo.<\/p>\n\n\n\n
<\/a>Figure 3. Mesentery<\/strong>\u00a0(Credit: scientificanimations.com,\u00a0CC BY-SA 4.0<\/a>)<\/figcaption><\/figure>\n\n\n<\/span>\n Mesocolon<\/h4>\n<\/span>\n\n\n
The mesocolon is the collective name for the peritoneal folds that attach the large intestine to the posterior abdominal wall.<\/p>\n\n\n\n
- It allows movement to a certain degree and engulfs the neurovasculature associated with the large intestine.<\/li>
- The anterior layer of the transverse mesocolon adheres to the posterior layer of the greater omentum.<\/li>
- It can be divided based on the part of the intestine it is attached to:
- The mesoappendix<\/strong><\/li>
- Ascending mesocolon<\/strong><\/li>
- Transverse mesocolon<\/strong><\/li>
- Descending mesocolon<\/strong><\/li>
- Sigmoid mesocolon<\/strong><\/li>
- Mesorectum<\/strong><\/li>
- Note that the cecum has no separate mesocolon<\/li><\/ul><\/li><\/ul>\n\n\n\n
<\/a>Figure 4. Mesocolon and mesentery<\/strong><\/figcaption><\/figure>\n\n\n<\/span>\n Peritoneal cavity<\/h3>\n<\/span>\n\n\n
The peritoneal cavity is a collapsed space containing only tiny amounts of serous fluid for lubrication.<\/p>\n\n\n\n
There are two approaches in dividing it:<\/p>\n\n\n\n
- The greater<\/strong> and lesser sacs<\/strong><\/li>
- The supracolic <\/strong>and infracolic compartments<\/strong><\/li><\/ul>\n\n\n<\/span>\n
Greater and lesser sacs<\/h4>\n<\/span>\n\n\n
- The greater sac<\/strong>, as its name suggests, is the greater portion of the peritoneal cavity.
- Formed between the parietal and visceral peritoneum.<\/li>
- It starts from the inferior surface of the diaphragm, down to the floor of the abdominal cavity (above the pelvis).<\/li><\/ul><\/li>
- The lesser sac<\/strong>, or omental bursa<\/strong>, is the lesser portion of the peritoneal cavity.
- Located posterior to the stomach and liver.<\/li>
- Communicates with the greater sac via the omental<\/strong> foramen <\/strong>(or epiploic foramen of Winslow<\/strong>).
- The omental foramen is surrounded by the following structures:
- Superiorly<\/strong> \u2014 The liver<\/li>
- Inferiorly<\/strong> \u2014 The duodenum<\/li>
- Anteriorly <\/strong>\u2014 Hepatoduodenal ligament (containing the portal vein, hepatic artery proper, and bile duct)<\/li>
- Posteriorly<\/strong> \u2014 Inferior vena cava<\/li><\/ul><\/li><\/ul><\/li><\/ul><\/li><\/ul>\n\n\n\n
<\/a>Figure 5. A cross-section showing the sacs of the peritoneal cavity<\/strong>\u00a0(Credit: Dennis M DePace, PhD,\u00a0CC BY-SA 4.0<\/a>)<\/figcaption><\/figure>\n\n\n<\/span>\n Supracolic and infracolic compartments<\/h4>\n<\/span>\n\n\n
The transverse colon divides the peritoneal cavity into the supracolic<\/strong> and infracolic<\/strong> compartments.<\/p>\n\n\n\n
- The supracolic compartment is located above the transverse colon.<\/li>
- The infracolic compartment is located below the transverse colon.<\/li><\/ul>\n\n\n<\/span>\n
Organs<\/h3>\n<\/span>\n\n\n
Organs completely covered by peritoneum are referred to as intra-peritoneal<\/strong>:<\/p>\n\n\n\n
- These organs are covered immediately by a visceral layer of peritoneum, which is continuous with the abdominal wall dorsally (and ventrally in the foregut \u2014 stomach and liver), and allows the passage the nerves and vessels, through the mesentery<\/strong>
- Stomach<\/li>
- The first part of the duodenum<\/li>
- Small intestine<\/li>
- Transverse colon<\/li>
- Sigmoid colon<\/li>
- Liver<\/li>
- Spleen<\/li>
- The tail of the Pancreas<\/li>
- In women \u2014 The body of the uterus, the fallopian tubes, and the ovaries
- The ovaries are the only organ truly located within the peritoneal cavity, and the fallopian tubes form an opening to it (as mentioned above).<\/li>
- Oocytes released from the ovaries are initially located within the peritoneal cavity, before being swept into the uterine tubes through their opening by the fimbriae.<\/li><\/ul><\/li><\/ul><\/li><\/ul>\n\n\n\n
Those covered only partially are either retro-<\/strong> or infra-peritoneal<\/strong><\/p>\n\n\n\n
- Retroperitoneal<\/strong> organs are located posterior to the peritoneum \u2014 hence, are only covered by peritoneum anteriorly
- The remainder of the duodenum<\/li>
- Cecum<\/li>
- Ascending colon<\/li>
- Descending colon<\/li>
- The majority of the pancreas<\/li>
- The kidneys.<\/li>
- View the retroperitoneum lesson<\/a> for more information<\/li><\/ul><\/li>
- Infraperitoneal<\/strong> organs are located below the peritoneum \u2014 hence, are only covered by peritoneum superiorly; these are the pelvic organs, discussed below.<\/li><\/ul>\n\n\n<\/span>\n
Peritoneal relations in the pelvis<\/h3>\n<\/span>\n\n<\/span>\n
Females<\/h4>\n<\/span>\n\n\n
- Descends on the anterior abdominal wall, forming the supravesical fossa over the bladder, and the paravesical fossae to the sides of the bladder.<\/li>
- Reflects from the superior surface of the bladder onto the uterus forming the vesicouterine pouch.<\/li>
- Covers the body and fundus of the uterus and the posterior fornix of the vagina, extending laterally to blend with the broad ligament of the uterus.<\/li>
- The posterior reflection covers the rectum forming the rectouterine pouch (Douglas pouch), with the pararectal fossae to the sides of the rectum.<\/li><\/ol>\n\n\n\n<\/a>
Figure 6. The peritoneal relations of the female pelvis (in blue)<\/strong>\u00a0(Credit: BruceBlaus,\u00a0CC BY-SA 4.0<\/a>)<\/figcaption><\/figure>\n\n\n<\/span>\n Males<\/h4>\n<\/span>\n\n\n
- Descends on the anterior abdominal wall, forming the supravesical fossa over the bladder, and the paravesical fossae to the sides of the bladder.<\/li>
- Descends on the posterior surface of the bladder, covering the ureters, ductus deferens, and the superior edge of the seminal glands (a reflection known as the ureteric fold).<\/li>
- The posterior reflection covers the rectum forming the rectovesical pouch (Douglas pouch), with the pararectal fossae to the sides of the rectum.<\/li><\/ol>\n\n\n<\/span>\n
Embryology<\/h3>\n<\/span>\n\n\n
During the development of the GIT and the associated tissues, the mesogastrium <\/strong>serves as an origin for the developing peritoneum, adhering the primitive gut to the body wall.<\/p>\n\n\n\n
The mesogastrium is divided into the ventral<\/strong> and dorsal<\/strong> portions:<\/p>\n\n\n\n
- The ventral mesogastrium<\/strong> is present only at the region of the foregut:
- It extends from the lesser curvature to the septum transversum and the anterior abdominal wall.<\/li>
- It disappears almost completely, and gives rise to several structures related to the liver:
- Falciform ligament<\/li>
- Right and left triangular ligaments<\/li>
- Coronary ligaments<\/li>
- Lesser omentum<\/li><\/ul><\/li><\/ul><\/li>
- The dorsal mesogastrium<\/strong> is present throughout the GIT (foregut, midgut, and hindgut):
- It extends from the greater curvature of the stomach to the posterior abdominal wall.<\/li>
- It gives rise to:
- The greater omentum<\/li>
- Gastrosplenic ligament<\/li>
- Splenorenal ligament<\/li><\/ul><\/li><\/ul><\/li><\/ul>\n\n\n\n<\/a>
Figure 7. An illustration of the development of the GIT<\/strong><\/figcaption><\/figure>\n<\/span>
- The ventral mesogastrium<\/strong> is present only at the region of the foregut:
- Infraperitoneal<\/strong> organs are located below the peritoneum \u2014 hence, are only covered by peritoneum superiorly; these are the pelvic organs, discussed below.<\/li><\/ul>\n\n\n<\/span>\n
- Retroperitoneal<\/strong> organs are located posterior to the peritoneum \u2014 hence, are only covered by peritoneum anteriorly
- These organs are covered immediately by a visceral layer of peritoneum, which is continuous with the abdominal wall dorsally (and ventrally in the foregut \u2014 stomach and liver), and allows the passage the nerves and vessels, through the mesentery<\/strong>
- Inferiorly<\/strong> \u2014 The duodenum<\/li>
- Superiorly<\/strong> \u2014 The liver<\/li>
- The omental foramen is surrounded by the following structures:
- The supracolic <\/strong>and infracolic compartments<\/strong><\/li><\/ul>\n\n\n<\/span>\n
- Ascending mesocolon<\/strong><\/li>
- The mesoappendix<\/strong><\/li>
- Mesentery<\/strong> \u2014 Small intestine<\/li>
- Omenta <\/strong>\u2014 Stomach<\/li>
![\"\"](\"https:\/\/meddists.com\/wp-content\/uploads\/2018\/10\/organs-omenta.png\")
<\/a>