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Peritoneum

The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal (or coelomic) organs, and is composed of a layer of mesothelium supported by a thin layer of connective tissue. This peritoneal lining of the cavity supports many of the abdominal organs and serves as a conduit for their blood vessels, lymphatic vessels, and nerves.

Peritoneum
The peritoneum, colored in blue
The epiploic foramen, greater sac or general cavity (red) and lesser sac, or omental bursa (blue)
Details
Pronunciation/ˌpɛrɪtəˈnəm/
Part ofAbdomen
Identifiers
LatinPeritoneum
MeSHD010537
TA98A10.1.02.002
A10.1.02.005
A10.1.02.006
TA23729
THH3.04.08.0.00001
FMA9584
Anatomical terminology
[edit on Wikidata]

The abdominal cavity (the space bounded by the vertebrae, abdominal muscles, diaphragm, and pelvic floor) is different from the intraperitoneal space (located within the abdominal cavity but wrapped in peritoneum). The structures within the intraperitoneal space are called "intraperitoneal" (e.g., the stomach and intestines), the structures in the abdominal cavity that are located behind the intraperitoneal space are called "retroperitoneal" (e.g., the kidneys), and those structures below the intraperitoneal space are called "subperitoneal" or "infraperitoneal" (e.g., the bladder).

Structure Edit

Layers Edit

The peritoneum is one continuous sheet, forming two layers and a potential space between them: the peritoneal cavity.

The outer layer, the parietal peritoneum, is attached to the abdominal wall and the pelvic walls.[1] The tunica vaginalis, the serous membrane covering the male testis, is derived from the vaginal process, an outpouching of the parietal peritoneum.

The inner layer, the visceral peritoneum, is wrapped around the visceral organs, located inside the intraperitoneal space for protection. It is thinner than the parietal peritoneum. The mesentery is a double layer of visceral peritoneum that attaches to the gastrointestinal tract. There are often blood vessels, nerves, and other structures between these layers. The space between these two layers is technically outside of the peritoneal sac, and thus not in the peritoneal cavity.

The potential space between these two layers is the peritoneal cavity, filled with a small amount (about 50 mL) of slippery serous fluid that allows the two layers to slide freely over each other.

The right paracolic gutter is continuous with the right and left subhepatic spaces. The epiploic foramen allows communication between the greater sac and the lesser sac.[2] The peritoneal space in males is closed, while the peritoneal space in females is continuous with the extraperitoneal pelvis through openings of the fallopian tubes, the uterus, and the vagina.[3]

Subdivisions Edit

Peritoneal folds are omentums, mesenteries and ligaments; they connect organs to each other or to the abdominal wall.[4] There are two main regions of the peritoneal cavity, connected by the omental foramen.

The mesentery is the part of the peritoneum through which most abdominal organs are attached to the abdominal wall and supplied with blood and lymph vessels and nerves.

Omenta Edit

Sources Structure From To Contains
Dorsal mesentery Greater omentum Greater curvature of stomach (and spleen) Transverse colon right and left gastroepiploic vessels and fat
Gastrosplenic ligament Stomach Spleen Short gastric artery, Left gastroepiploic artery
Gastrophrenic ligament Stomach Diaphragm Left inferior phrenic artery
Gastrocolic ligament Stomach Transverse colon Right gastroepiploic artery
Splenorenal ligament Spleen Kidney Splenic artery, Tail of pancreas
Ventral mesentery Lesser omentum Lesser curvature of the stomach (and duodenum) Liver The right free margin-hepatic artery, portal vein, and bile duct,lymph nodes and the lymph vessels,hepatic plexus of nerve,all enclosed in perivascular fibrous sheath. Along the lesser curvature of the stomach-left and right gastric artery,gastric group of lymph nodes and lyphatics, branches from gastric nerve.
Hepatogastric ligament Stomach Liver Right and left gastric artery
Hepatoduodenal ligament Duodenum Liver Hepatic artery proper, hepatic portal vein, bile duct, autonomic nerves

Mesenteries Edit

Sources Structure From To Contains
Dorsal mesentery Mesentery proper Small intestine (jejunum and ileum) Posterior abdominal wall Superior mesenteric artery, accompanying veins, autonomic nerve plexuses, lymphatics, 100–200 lymph nodes and connective tissue with fat
Transverse mesocolon Transverse colon Posterior abdominal wall Middle colic
Sigmoid mesocolon Sigmoid colon Pelvic wall Sigmoid arteries and superior rectal artery
Mesoappendix Mesentery of ileum Appendix Appendicular artery

Other ligaments and folds Edit

In addition, in the pelvic cavity there are several structures that are usually named not for the peritoneum, but for the areas defined by the peritoneal folds:

Name Location Sexes possessing structure
Rectovesical pouch Between rectum and urinary bladder Male only
Rectouterine pouch Between rectum and uterus Female only
Vesicouterine pouch Between urinary bladder and uterus Female only
Pararectal fossa Surrounding rectum Male and female
Paravesical fossa Surrounding urinary bladder Male and female

Classification of abdominal structures Edit

The structures in the abdomen are classified as intraperitoneal, mesoperitoneal, retroperitoneal or infraperitoneal depending on whether they are covered with visceral peritoneum and whether they are attached by mesenteries (mensentery, mesocolon).

Intraperitoneal Mesoperitoneal Retroperitoneal ( or Extraperitoneal ) Infraperitoneal / Subperitoneal
Stomach, half of the first part of the duodenum [2.2 cm], jejunum, ileum, cecum, appendix, transverse colon, sigmoid colon, rectum (upper 1/3) The rest of the duodenum, ascending colon, descending colon, rectum (middle 1/3) Rectum (lower 1/3)
Spleen, pancreas (only tail) Liver Pancreas (except tail)
Kidneys, adrenal glands, proximal ureters, renal vessels Urinary bladder, distal ureters
In women: ovaries Gonadal blood vessels, Uterus, Fallopian Tubes
Inferior vena cava, aorta

Structures that are intraperitoneal are generally mobile, while those that are retroperitoneal are relatively fixed in their location.

Some structures, such as the kidneys, are "primarily retroperitoneal", while others such as the majority of the duodenum, are "secondarily retroperitoneal", meaning that structure developed intraperitoneally but lost its mesentery and thus became retroperitoneal.

Development Edit

The peritoneum develops ultimately from the mesoderm of the trilaminar embryo. As the mesoderm differentiates, one region known as the lateral plate mesoderm splits to form two layers separated by an intraembryonic coelom. These two layers develop later into the visceral and parietal layers found in all serous cavities, including the peritoneum.

As an embryo develops, the various abdominal organs grow into the abdominal cavity from structures in the abdominal wall. In this process they become enveloped in a layer of peritoneum. The growing organs "take their blood vessels with them" from the abdominal wall, and these blood vessels become covered by peritoneum, forming a mesentery.[6]

Peritoneal folds develop from the ventral and dorsal mesentery of the embryo.[4]

Clinical significance Edit

Imaging assessment Edit

CT scan is a fast (15 seconds) and efficient way in visualising the peritoneal spaces. Although ultrasound is good at visualizing peritoneal collections and ascites, without ionising radiation, it does not provide a good overall assessment of all the peritoneal cavities. MRI scan is also increasingly used to visualise peritoneal diseases, but requires long scan time (30 to 45 minutes) and prone to motion artifacts due to respiration and peristalsis and chemical shift artifacts at the bowel-mesentery interface. Those with peritoneal carcinomatosis, acute pancreatitis, and intraabdominal sepsis may not tolerate prolonged MRI scan.[3]

Peritoneal dialysis Edit

In one form of dialysis, called peritoneal dialysis, a glucose solution is sent through a tube into the peritoneal cavity. The fluid is left there for a prescribed amount of time to absorb waste products, and then removed through the tube. The reason for this effect is the high number of arteries and veins in the peritoneal cavity. Through the mechanism of diffusion, waste products are removed from the blood.

Peritonitis Edit

Peritonitis is the inflammation of the peritoneum. It is more commonly associated to infection from a punctured organ of the abdominal cavity. It can also be provoked by the presence of fluids that produce chemical irritation, such as gastric acid or pancreatic juice. Peritonitis causes fever, tenderness, and pain in the abdominal area, which can be localized or diffuse. The treatment involves rehydration, administration of antibiotics, and surgical correction of the underlying cause. Mortality is higher in the elderly and if present for a prolonged time.[7]

Primary peritoneal carcinoma Edit

Primary peritoneal cancer is a cancer of the cells lining the peritoneum.

Etymology Edit

"Peritoneum" is derived from Greek: περιτόναιον, romanizedperitonaion, lit.'peritoneum, abdominal membrane'[8] via Latin. In Greek, περί, peri means "around", while τείνω, teino means "to stretch"; thus, "peritoneum" means "stretched over".[8]

Additional images Edit

See also Edit

References Edit

  1. ^ Tank PW (2013). "Chapter 4: The abdomen". Grant's dissector (Fifteenth ed.). Philadelphia. ISBN 978-1-60913-606-2.{{cite book}}: CS1 maint: location missing publisher (link)
  2. ^ Jones, J. (14 April 2009). Epiploic Foramen | Radiopaedia.org. Radiopaedia. doi:10.53347/rID-6059. Retrieved 21 May 2022.
  3. ^ a b Tirkes, Temel; Sandrasegaran, Kumaresan; Patel, Aashish A.; Hollar, Margaret A.; Tejada, Juan G.; Tann, Mark; Akisik, Fatih M.; Lappas, John C. (March 2012). "Peritoneal and Retroperitoneal Anatomy and Its Relevance for Cross-Sectional Imaging". RadioGraphics. 32 (2): 437–451. doi:10.1148/rg.322115032. ISSN 0271-5333. PMID 22411941.
  4. ^ a b Drake, R. L.; Vogl, A.W.; Mitchell, A.W. (4 April 2009). "Abdominal Viscera". Gray's Anatomy for Students. Philadelphia, PA: Elsevier Health Sciences. p. 295. ISBN 9781437720556. OCLC 489070574.
  5. ^ a b c Tortora GJ, Anagnostakos NP (1984). Principles of anatomy and physiology (4th ed.). New York: Harper & Row. ISBN 978-0-06-046656-5.
  6. ^ (PDF). healthoracle.org. Archived from the original (PDF) on 23 April 2016. Retrieved 14 April 2018.
  7. ^ Longo D, Fauci A, Kasper D, Hauser S, Jameson J, Loscalzo J (2012). Harrison's Principles of Internal Medicine (18th ed.). New York: McGraw-Hill. pp. 2518–2519. ISBN 978-0-07-174889-6.
  8. ^ a b "Peritoneum - Origin and meaning of peritoneum by Online Etymology Dictionary". www.etymonline.com. Retrieved 14 April 2018.
  9. ^ Image by Mikael Häggström, MD. Sources for mentioned features:
    - "Mesothelial cytopathology". Libre Pathology. Retrieved 2022-10-18.
    - Shidham VB, Layfield LJ (2021). "Introduction to the second edition of 'Diagnostic Cytopathology of Serous Fluids' as CytoJournal Monograph (CMAS) in Open Access". CytoJournal. 18: 30. doi:10.25259/CMAS_02_01_2021. PMC 8813611. PMID 35126608.

External links Edit

peritoneum, confused, with, perineum, peritoneal, redirects, here, confused, with, perineal, peroneal, intraperitoneal, redirects, here, intraperitoneal, route, administration, intraperitoneal, injection, peritoneum, serous, membrane, forming, lining, abdomina. Not to be confused with Perineum Peritoneal redirects here It is not to be confused with Perineal or Peroneal Intraperitoneal redirects here For the intraperitoneal route of administration see intraperitoneal injection The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates such as annelids It covers most of the intra abdominal or coelomic organs and is composed of a layer of mesothelium supported by a thin layer of connective tissue This peritoneal lining of the cavity supports many of the abdominal organs and serves as a conduit for their blood vessels lymphatic vessels and nerves PeritoneumThe peritoneum colored in blueThe epiploic foramen greater sac or general cavity red and lesser sac or omental bursa blue DetailsPronunciation ˌ p ɛr ɪ t e ˈ n iː em Part ofAbdomenIdentifiersLatinPeritoneumMeSHD010537TA98A10 1 02 002 A10 1 02 005 A10 1 02 006TA23729THH3 04 08 0 00001FMA9584Anatomical terminology edit on Wikidata The abdominal cavity the space bounded by the vertebrae abdominal muscles diaphragm and pelvic floor is different from the intraperitoneal space located within the abdominal cavity but wrapped in peritoneum The structures within the intraperitoneal space are called intraperitoneal e g the stomach and intestines the structures in the abdominal cavity that are located behind the intraperitoneal space are called retroperitoneal e g the kidneys and those structures below the intraperitoneal space are called subperitoneal or infraperitoneal e g the bladder Contents 1 Structure 1 1 Layers 1 2 Subdivisions 1 2 1 Omenta 1 2 2 Mesenteries 1 2 3 Other ligaments and folds 1 3 Classification of abdominal structures 1 4 Development 2 Clinical significance 2 1 Imaging assessment 2 2 Peritoneal dialysis 2 3 Peritonitis 2 4 Primary peritoneal carcinoma 3 Etymology 4 Additional images 5 See also 6 References 7 External linksStructure EditLayers Edit The peritoneum is one continuous sheet forming two layers and a potential space between them the peritoneal cavity The outer layer the parietal peritoneum is attached to the abdominal wall and the pelvic walls 1 The tunica vaginalis the serous membrane covering the male testis is derived from the vaginal process an outpouching of the parietal peritoneum The inner layer the visceral peritoneum is wrapped around the visceral organs located inside the intraperitoneal space for protection It is thinner than the parietal peritoneum The mesentery is a double layer of visceral peritoneum that attaches to the gastrointestinal tract There are often blood vessels nerves and other structures between these layers The space between these two layers is technically outside of the peritoneal sac and thus not in the peritoneal cavity The potential space between these two layers is the peritoneal cavity filled with a small amount about 50 mL of slippery serous fluid that allows the two layers to slide freely over each other The right paracolic gutter is continuous with the right and left subhepatic spaces The epiploic foramen allows communication between the greater sac and the lesser sac 2 The peritoneal space in males is closed while the peritoneal space in females is continuous with the extraperitoneal pelvis through openings of the fallopian tubes the uterus and the vagina 3 Subdivisions Edit Peritoneal folds are omentums mesenteries and ligaments they connect organs to each other or to the abdominal wall 4 There are two main regions of the peritoneal cavity connected by the omental foramen The greater sac represented in red in the diagrams above The lesser sac represented in blue The lesser sac is divided into two omenta The lesser omentum or hepatogastric is attached to the lesser curvature of the stomach and the liver 5 The greater omentum or gastrocolic hangs from the greater curvature of the stomach and loops down in front of the intestines before curving back upwards to attach to the transverse colon 5 In effect it is draped in front of the intestines like an apron and may serve as an insulating or protective layer 5 The mesentery is the part of the peritoneum through which most abdominal organs are attached to the abdominal wall and supplied with blood and lymph vessels and nerves Omenta Edit Sources Structure From To ContainsDorsal mesentery Greater omentum Greater curvature of stomach and spleen Transverse colon right and left gastroepiploic vessels and fatGastrosplenic ligament Stomach Spleen Short gastric artery Left gastroepiploic arteryGastrophrenic ligament Stomach Diaphragm Left inferior phrenic arteryGastrocolic ligament Stomach Transverse colon Right gastroepiploic arterySplenorenal ligament Spleen Kidney Splenic artery Tail of pancreasVentral mesentery Lesser omentum Lesser curvature of the stomach and duodenum Liver The right free margin hepatic artery portal vein and bile duct lymph nodes and the lymph vessels hepatic plexus of nerve all enclosed in perivascular fibrous sheath Along the lesser curvature of the stomach left and right gastric artery gastric group of lymph nodes and lyphatics branches from gastric nerve Hepatogastric ligament Stomach Liver Right and left gastric arteryHepatoduodenal ligament Duodenum Liver Hepatic artery proper hepatic portal vein bile duct autonomic nervesMesenteries Edit Sources Structure From To ContainsDorsal mesentery Mesentery proper Small intestine jejunum and ileum Posterior abdominal wall Superior mesenteric artery accompanying veins autonomic nerve plexuses lymphatics 100 200 lymph nodes and connective tissue with fatTransverse mesocolon Transverse colon Posterior abdominal wall Middle colicSigmoid mesocolon Sigmoid colon Pelvic wall Sigmoid arteries and superior rectal arteryMesoappendix Mesentery of ileum Appendix Appendicular arteryOther ligaments and folds Edit Sources Structure From To ContainsVentral mesentery Falciform ligament Liver Thoracic diaphragm anterior abdominal wall Round ligament of liver paraumbilical veinLeft umbilical vein Round ligament of liver Liver UmbilicusVentral mesentery Coronary ligament Liver Thoracic diaphragmDuctus venosus Ligamentum venosum Liver LiverPhrenicocolic ligament Left colic flexure Thoracic diaphragmVentral mesentery Left triangular ligament right triangular ligament LiverUmbilical folds Urinary bladderIleocecal fold Ileum CecumBroad ligament of the uterus Uterus Pelvic wall Mesovarium mesosalpinx mesometriumRound ligament of uterus Uterus Inguinal canalSuspensory ligament of the ovary Ovary Pelvic wall Ovarian arteryIn addition in the pelvic cavity there are several structures that are usually named not for the peritoneum but for the areas defined by the peritoneal folds Name Location Sexes possessing structureRectovesical pouch Between rectum and urinary bladder Male onlyRectouterine pouch Between rectum and uterus Female onlyVesicouterine pouch Between urinary bladder and uterus Female onlyPararectal fossa Surrounding rectum Male and femaleParavesical fossa Surrounding urinary bladder Male and femaleClassification of abdominal structures Edit The structures in the abdomen are classified as intraperitoneal mesoperitoneal retroperitoneal or infraperitoneal depending on whether they are covered with visceral peritoneum and whether they are attached by mesenteries mensentery mesocolon Intraperitoneal Mesoperitoneal Retroperitoneal or Extraperitoneal Infraperitoneal SubperitonealStomach half of the first part of the duodenum 2 2 cm jejunum ileum cecum appendix transverse colon sigmoid colon rectum upper 1 3 The rest of the duodenum ascending colon descending colon rectum middle 1 3 Rectum lower 1 3 Spleen pancreas only tail Liver Pancreas except tail Kidneys adrenal glands proximal ureters renal vessels Urinary bladder distal uretersIn women ovaries Gonadal blood vessels Uterus Fallopian TubesInferior vena cava aortaStructures that are intraperitoneal are generally mobile while those that are retroperitoneal are relatively fixed in their location Some structures such as the kidneys are primarily retroperitoneal while others such as the majority of the duodenum are secondarily retroperitoneal meaning that structure developed intraperitoneally but lost its mesentery and thus became retroperitoneal Development Edit The peritoneum develops ultimately from the mesoderm of the trilaminar embryo As the mesoderm differentiates one region known as the lateral plate mesoderm splits to form two layers separated by an intraembryonic coelom These two layers develop later into the visceral and parietal layers found in all serous cavities including the peritoneum As an embryo develops the various abdominal organs grow into the abdominal cavity from structures in the abdominal wall In this process they become enveloped in a layer of peritoneum The growing organs take their blood vessels with them from the abdominal wall and these blood vessels become covered by peritoneum forming a mesentery 6 Peritoneal folds develop from the ventral and dorsal mesentery of the embryo 4 Clinical significance EditImaging assessment Edit CT scan is a fast 15 seconds and efficient way in visualising the peritoneal spaces Although ultrasound is good at visualizing peritoneal collections and ascites without ionising radiation it does not provide a good overall assessment of all the peritoneal cavities MRI scan is also increasingly used to visualise peritoneal diseases but requires long scan time 30 to 45 minutes and prone to motion artifacts due to respiration and peristalsis and chemical shift artifacts at the bowel mesentery interface Those with peritoneal carcinomatosis acute pancreatitis and intraabdominal sepsis may not tolerate prolonged MRI scan 3 Peritoneal dialysis Edit Main article Peritoneal dialysis In one form of dialysis called peritoneal dialysis a glucose solution is sent through a tube into the peritoneal cavity The fluid is left there for a prescribed amount of time to absorb waste products and then removed through the tube The reason for this effect is the high number of arteries and veins in the peritoneal cavity Through the mechanism of diffusion waste products are removed from the blood Peritonitis Edit Main article Peritonitis Peritonitis is the inflammation of the peritoneum It is more commonly associated to infection from a punctured organ of the abdominal cavity It can also be provoked by the presence of fluids that produce chemical irritation such as gastric acid or pancreatic juice Peritonitis causes fever tenderness and pain in the abdominal area which can be localized or diffuse The treatment involves rehydration administration of antibiotics and surgical correction of the underlying cause Mortality is higher in the elderly and if present for a prolonged time 7 Primary peritoneal carcinoma Edit Main article Primary peritoneal carcinoma Primary peritoneal cancer is a cancer of the cells lining the peritoneum Etymology Edit Peritoneum is derived from Greek peritonaion romanized peritonaion lit peritoneum abdominal membrane 8 via Latin In Greek peri peri means around while teinw teino means to stretch thus peritoneum means stretched over 8 Additional images Edit Median sagittal section of pelvis showing the arrangement of fasciae Horizontal disposition of the peritoneum in the lower part of the abdomen Sagittal section through posterior abdominal wall showing the relations of the capsule of the kidney Topography of thoracic and abdominal viscera Horizontal disposition of the peritoneum in the upper part of the abdomen Cytology of the normal mesothelial cells that line the peritoneum with typical features 9 Wright s stainSee also EditDuodenorenal ligament Omental bursa Lesser sac Greater sac Omental foramen Epiploic foramen Foramen of Winslow Lesser omentum Greater omentumReferences Edit Tank PW 2013 Chapter 4 The abdomen Grant s dissector Fifteenth ed Philadelphia ISBN 978 1 60913 606 2 a href Template Cite book html title Template Cite book cite book a CS1 maint location missing publisher link Jones J 14 April 2009 Epiploic Foramen Radiopaedia org Radiopaedia doi 10 53347 rID 6059 Retrieved 21 May 2022 a b Tirkes Temel Sandrasegaran Kumaresan Patel Aashish A Hollar Margaret A Tejada Juan G Tann Mark Akisik Fatih M Lappas John C March 2012 Peritoneal and Retroperitoneal Anatomy and Its Relevance for Cross Sectional Imaging RadioGraphics 32 2 437 451 doi 10 1148 rg 322115032 ISSN 0271 5333 PMID 22411941 a b Drake R L Vogl A W Mitchell A W 4 April 2009 Abdominal Viscera Gray s Anatomy for Students Philadelphia PA Elsevier Health Sciences p 295 ISBN 9781437720556 OCLC 489070574 a b c Tortora GJ Anagnostakos NP 1984 Principles of anatomy and physiology 4th ed New York Harper amp Row ISBN 978 0 06 046656 5 Peritoneum PDF healthoracle org Archived from the original PDF on 23 April 2016 Retrieved 14 April 2018 Longo D Fauci A Kasper D Hauser S Jameson J Loscalzo J 2012 Harrison s Principles of Internal Medicine 18th ed New York McGraw Hill pp 2518 2519 ISBN 978 0 07 174889 6 a b Peritoneum Origin and meaning of peritoneum by Online Etymology Dictionary www etymonline com Retrieved 14 April 2018 Image by Mikael Haggstrom MD Sources for mentioned features Mesothelial cytopathology Libre Pathology Retrieved 2022 10 18 Shidham VB Layfield LJ 2021 Introduction to the second edition of Diagnostic Cytopathology of Serous Fluids as CytoJournal Monograph CMAS in Open Access CytoJournal 18 30 doi 10 25259 CMAS 02 01 2021 PMC 8813611 PMID 35126608 External links Edit Wikimedia Commons has media related to Peritoneum Retrieved from https en wikipedia org w index php title Peritoneum amp oldid 1145831279 Layers, wikipedia, wiki, book, books, library,

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