Index
Definition:
The peritoneum is a thin serous membrane that lines the walls of the abdominal and pelvic cavities and dresses the abdominal and pelvic viscera.
It is the most extensive serous membrane of the human body and has a pretty complex arrangement. The peritoneum of the living body has a certain degree of mobility on the extraperitoneal fat and can be stretched to a certain extent without tearing.
Peritoneal layers
The peritoneum can be considered a balloon in which the organs are pressed from the outside.
Because of this, two layers are formed. A layer covers the walls of the abdominal and pelvic cavities and is called the parietal peritoneum. The other layer covers the organs and is known as the visceral peritoneum. The space between the parietal and visceral layers, the globe’s interior, is called the peritoneal cavity.
Extraperitoneal tissue:
Between the parietal peritoneum and the facial lining of the abdominal and pelvic walls, there is a layer of connective tissue called extraperitoneal tissue. It varies in different regions.
In the area of the kidneys, it contains a large amount of fat, which provides support. In contrast to the parietal peritoneum, the visceral peritoneum is attached to the underlying viscera by only a tiny connective tissue.
Peritoneal cavity:
The peritoneal cavity is a potential space between the parietal and the visceral peritoneum. It contains a small amount of serous fluid, which is empty.
The fluid lubricates the visceral peritoneum and allows the moving viscera to slide freely over the abdominal wall. They contain water, proteins, electrolytes, and solutes derived from interstitial fluid in adjacent tissues and plasma in local blood vessels.
In men, the peritoneal cavity is closed, but there is communication with the outside through the uterine tubes, the uterus and the vagina in females.
Divisions of the peritoneal cavity
The peritoneal cavity is the largest in the human body, and the surface of the parietal and visceral layers is enormous. The entire peritoneal cavity can be divided into Saco mayor and Saco menor.
- Larger sac: It is the main compartment of the peritoneal cavity and extends from the diaphragm down into the pelvis.
- Small sac: It is smaller and is located behind the stomach. It is inaccessible communication with the larger sac through an oval window called the opening of the lower sac, or “epiploic hole.”
Classification of abdominal structures about the peritoneum
Based on their relationship with the peritoneum, the abdominal structures are classified into Intraperitoneal, Retroperitoneal, and Intraperitoneal.
Intraperitoneal organs: It is said that an organ is intraperitoneal when it is almost wholly covered with visceral peritoneum. The intraperitoneal organs of the human body are:
- Stomach
- The first part of the duodenum
- Yeyo
- Ilion
- Cecum
- Appendix
- Colon transverse
- Colon sigmoid
- 1/3 top of the rectum
- Liver
- Base
- Uterus (females)
- Fallopian tubes (females)
- Ovaries (women)
- Retroperitoneal organs: These are organs that are behind the peritoneum and are only partially covered by the visceral peritoneum. The retroperitoneal organs of the human body are:
- Second and third parts of the duodenum
- Ascending colon
- Descending colon
- Half 1/3 of the rectum
- Pancreas
- Kidneys
- Kidney glands
- Proximal ureters
- Kidney vessels
- Gonadal blood vessels
- A vein from the lower cavity
- Aorta
Intraperitoneal Organs: These are organs inferior to the peritoneum of the pelvis. These include:
- Under 1/3 of the rectum
- Urinary bladder
- Distal ureters
Important: The intraperitoneal structures are generally mobile, while those that are retroperitoneal are relatively fixed in their location.
It must be taken into account that no organ is inside the peritoneal cavity. The intraperitoneal organs are surrounded by the peritoneal cavity but are covered with the visceral peritoneum that separates them.
Peritoneal ligaments, the omenta, and mesenteries:
- Ligaments: The peritoneal ligaments are two folds of layers of peritoneum that connect the viscera to the abdomen walls. Unlike other ligaments of the body, they do not possess dense fibrous tissue and are unique.
An excellent example of peritoneal ligaments is found in the liver, connected to the diaphragm by the falciform ligament, coronary ligament, and right and left triangular ligaments.
- Onto: The omentum consists of two angled folds of the peritoneum that connect the stomach to other viscera. There are three apparent omissions in the human body: Omento mayor, omentum menor, and gastrosplenic omentum.
- Major Omento: Connects the greater curvature of the stomach to the transverse colon. It hangs like an apron on the spirals of the small intestine and folds over itself to be joined to the transverse colon.
- Minor Osment: suspends the minor curvature of the stomach from the fissure of the venous ligament (fibrous remnants of the venous duct of the fetal circulation).
- Gastrosplenic moment: As the name suggests, connects the stomach with the hilum of the spleen.
- Mesenteries are two angled folds of the peritoneum that connect the intestine’s parts to the posterior abdominal wall. For example, the mesentery of the small intestine joins the coils of the jejunum and the ileum with the rear abdominal wall.
The ligaments, moments, and mesenteries allow the blood, lymphatic and nervous vessels to reach the viscera without perforating the peritoneum.
Bags, recesses, and peritoneal gutters:
The peritoneum is a highly folded membrane that results in the formation of many bags, recesses, and gutters. Some of the most important them are listed below:
Bags:
- Smaller bag
- Senior sac
Depths:
- Duodenal recesses
- Cecal recesses
- Intersigmoid recesses
Spaces:
- Subphrenic spaces
Gutters:
- Paracolic gutters
Blood supply and lymphatic drainage of the peritoneum
The parietal peritoneum is supplied by the somatic blood vessels of the abdominal and pelvic walls. Your lymph nodes join those in the body wall and drain into the parietal lymph nodes.
The visceral peritoneum is best considered an integral part of the viscera that overlap. It derives its blood supply from the viscera, and its lymph nodes join the visceral vessels to drain the regional lymph nodes.
Supply of nerves to the peritoneum
The supply of nerves to the parietal peritoneum
The parietal peritoneum is sensitive to pain, temperature, touch, and pressure. It is innervated according to the region where it exists, as explained below:
The six lower thoracic and lumbar nerves supply the parietal peritoneum that lines the anterior abdominal wall. It should be noted that these are the same nerves that supply the muscles and skin of the anterior abdominal wall.
In the region of the diaphragm, the supply of nerves is different. The phrenic nerves innervate the central part of the diaphragmatic peritoneum. Peripherally, the source of the nerve comes through the six lower thoracic nerves.
