Your peritoneum is a membrane that lines the inside of your abdomen and pelvis (parietal layer). It also covers many of your organs inside (visceral layer). The space in between these layers is called your peritoneal cavity. Folds of tissue form double layers, including your omentum, which hangs down the front of your abdomen, and your mesentery in the back.
Your peritoneum is a membrane, a sheet of smooth tissue that lines your abdominopelvic cavity and surrounds your abdominal organs. It pads and insulates your organs, helps hold them in place and secretes a lubricating fluid to reduce friction when they rub against each other. Your parietal peritoneum lines your abdominal and pelvic walls and your visceral peritoneum wraps around your organs. Your peritoneal cavity is the space in between.
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Your peritoneum has several functions, some of which researchers are still learning about. It provides:
Your abdominopelvic cavity is between your diaphragm and your pelvic floor. It includes your abdominal cavity and pelvic cavity. Your parietal peritoneum lines the walls of this cavity. Your visceral peritoneum wraps around your abdominal organs, particularly your stomach, liver, spleen and parts of your small and large intestines. Organs inside of your visceral peritoneum are called “intraperitoneal.” The others are “retroperitoneal.”
Your peritoneum is a serous membrane (the type that secretes serum). Tissue of this kind lines several of your body cavities and is generally known as mesothelium. It’s composed of epithelial cells on the top layer with connective tissue underneath. The epithelial cells secrete and absorb fluid, filter out particles and carry blood, lymph and nerve supply. The connective tissue holds everything together. It attaches some organs to your abdominal wall and suspends others inside the cavity.
Your visceral peritoneum folds upon itself as it wraps around your organs, creating double layers and pouches here and there. A large double layer called the omentum covers the front of your abdomen like an apron. A double layer in the back called the mesentery attaches your intestines to your back abdominal wall. The fat between the layers (adipose tissue) provides extra insulation and protection and carries neurovascular supply to your organs.
Your visceral peritoneum that covers your abdominal organs shares the same autonomic nerve supply as those organs. It perceives a visceral type of pain, which is diffuse and hard to localize. It feels the stretch when your digestive organs are distended with food or gas. It also perceives chemical irritants, such as blood or bile leaks. Your parietal peritoneum shares the same somatic nerve supply as your abdominal wall that it covers. It perceives localized pressure, pain and temperature.
Abdominal pain and swelling are the most common symptoms of any condition affecting your peritoneum. Pain that feels vague or diffuse throughout your abdomen could be coming from your visceral peritoneum, the inside layer. Pain that’s more intense may indicate your outside parietal layer is irritated. Abdominal pain has many causes, but many of them do involve your peritoneum.
Peritoneal diseases are hard to predict or prevent, but you can help take care of yourself by taking your abdominal pain seriously. Don’t be shy about seeing your doctor, even if you’re not sure if you should be concerned. You can’t always tell by the severity of your symptoms how serious they are. Some of the most serious diseases only have mild or vague symptoms.
A note from Cleveland Clinic
Your peritoneum is what lies between your skin and most of your visceral organs. It encloses them in at least one and sometimes several layers. It offers protection, insulation, structure and blood and nerve supply. It also has powerful healing and immunity functions. By covering your organs, (peritoneum means “to stretch around,”) it acts as a sentinel to infection anywhere in your abdominopelvic cavity. Inflammation in your peritoneum could be the first alarm that draws your attention to an unsuspected condition affecting one of your organs.
Last reviewed by a Cleveland Clinic medical professional on 04/27/2022.
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