Anatomy of peritoneum with applied aspects.
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Peritoneum, the derivative of mesoderm.
Anatomy of peritoneum with applied aspects.
- 2. PERITONEUM Def:- a large thin serous membrane which lines the interior of the abdomino-pelvic cavity. • Made up of tough elastic tissue. • Lined by simple squamous (MESOTHELIUM)epithelium. • Consists of 2 layers: Outer parietal layer, Inner visceral layer. • Both these layers are separated by a potential space k/a peritoneal cavity. • A thin capillary film of peritoneal fluid is present b/w two layers.
- 3. • Initially the peritoneum is just a closed sac. • Later it is invaginated by abdominal viscera. • Now it has got 2 layers. • The folds of peritoneum by which viscera are suspended to the body wall are called mesentery.
- 4. DIFFERENCE B/W MALE & FEMALE PERITONEUM • In males the peritoneum is a closed serous sac. • In females the sac is not closed rather it is open to the exterior through uterine tubes, uterus and vagina.
- 5. FOLDS OF PERITONEUM • Functions: – Provide suspension to many abdominal viscera. – Provide mobility to the viscera. – Provide passage to vessels and nerves. • Classification: • There are four types of peritoneal folds- 1.) Mesentery, 2.) Mesocolon, 3.) Omenta, 4.) Ligaments.
- 6. • Mesentery- fold suspending the small intestine. • Mesocolon- fold suspending the large intestine. • Omenta- folds that connect stomach to other viscera. There are 2 types of omenta. • Ligaments- connect organs to the abdominal wall or to each other. There are 3 types of peritoneal ligaments.
- 7. OMENTA • Lesser Omentum: connects stomach to the liver. • Greater Omentum: connects stomach to the transverse colon.
- 8. PERITONEAL LIGAMENTS • Gastrosplenic ligament: lies b/w stomach & spleen. • Lienorenal ligament: lies b/w kidney & spleen. • Coronary ligaments: lie b/w liver & diaphragm.
- 9. EMBRYOLOGICAL BASIS OF PERITONEAL FOLDS • The abdominal part of foregut has both ventral & dorsal mesentries. • The ventral mesentry is k/a ventral mesogastrium. • The dorsal mesentry is k/a dorsal mesogastrium. • The developing liver divides the ventral mesogastrium into ventral & dorsal parts.
- 10. FATE OF VENTRAL MESOGASTRIUM • Ventral part of ventral mesogastrium forms the falciform & the coronary ligaments of the liver. • Dorsal part of ventral mesogastrium forms the lesser omentum.
- 11. • Caudal part of the dorsal mesogastrium forms the greater omentum. • Cranial part of the dorsal mesogastrium is divided into ventral and dorsal parts by the developing spleen. • Ventral part forms the gastrosplenic ligament. • Dorsal part forms the lienorenal & gastrophrenic ligaments. FATE OF DORSAL MESOGASTRIUM
- 13. • The midgut and hindgut has only the dorsal mesentery. • Fate of dorsal mesentery: a.) forms the mesentery of jejunum & Ileum b.) forms the mesentery of appendix- Mesoappendix. c.) forms the mesentery of transverse colon- transverse mesocolon. d.) forms the mesentery of sigmoid colon- sigmoid mesocolon.
- 14. GREATER OMENTUM= (apron) POLICEMAN OF THE ABDOMEN • Thick fold of peritoneum. • Hangs from the greater curvature of the stomach. • Covers the loops of intestine. • Made up of 4 layers. • The layers are fused together and contain fatty tissue.
- 15. ATTACHMENTS OF GREATER OMENTUM • Anterior 2 layers are attached to the greater curvature of the stomach. • These 2 layers are continuous with the peritoneum covering the anterior and posterior surfaces of the stomach. • These layers then fold upon themselves to form the posterior two layers.
- 16. ATTACHMENTS OF GREATER OMENTUM • Folding occurs in a manner that the 1st layer becomes the 4th layer while the 2nd layer becomes the 3rd layer. • Posterior layers ascend up to become continuous with the peritoneum covering the transverse colon.
- 17. CONTENTS 1. )Variable amount of fat. 2.) Aggregation of macrophages which form the ‘MILKY spots’. 3.) Right and left gastroepiploic vessels.
- 18. FUNCTIONS OF GREATER OMENTUM 1.) Store house of fat. 2.) Protects the peritoneal cavity from infection due to large no. of macrophages present in it. 3.) Limits the spread of infection by sealing the infection from the surrounding areas. 4.) It also moves to the site of perforation of gut and plugs it thus preventing the leakage of its contents into the peritoneal cavity. 5.) Forms a partition b/w the supracolic and the infracolic compartments of the peritoneal cavity.
- 19. LESSER OMENTUM • Double layered fold of peritoneum. • Extends between the lesser curvature of stomach and the inferior surface of liver. • Attachments: • Inferiorly: – Right side of the abdominal part of oesophagus. – Lesser curvature of stomach. – First 2 cm of the duodenum. • Superiorly: Attached on the undersurface of liver in an inverted ‘L’ shaped manner to the: – Fissure for ligamentum venosum and – Porta hepatis.
- 20. ATTACHMENTS OF LESSER OMENTUM
- 21. CONTENTS OF LESSER OMENTUM • Along the lesser curvature of stomach: – Right and left gastric vessels and associated lymph nodes. – Branches of left gastric nerve. • Along the right free margin: – Posteriorly portal vein. – Anterior to portal vein: • Hepatic artery & • Bile duct (on right side of artery) – Autonomic nerves, – Lymphatics and lymph nodes.
- 22. MESENTERY OF SMALL INTESTINE • Fan shaped fold of peritoneum. • Suspends the coils of jejunum & ileum with the posterior abdominal wall. • Presents two parts: – Attached border (root) – Free border (intestinal border)-About 6 mtrs (20 feets) long.
- 23. ROOT OF MESENTERY • Attached to an oblique line on the posterior abdominal wall. • Extends from the duodenojejunal flexure (left side of L2 vertebra )to the ileocaecal junction (upper part of right sacroiliac joint). • It is 6 inches (15 cms) long.
- 24. STRUCTURES CROSSED BY ROOT OF MESENTERY • From above downwards crosses in front of: – Horizontal (3rd ) part of duodenum. – Abdominal aorta. – Inferior vena cava. – Right gonadal vessels. – Right ureter. – Right psoas major muscle.
- 25. FREE BORDER CONTENTS OF THE MESENTERY: – Superior mesenteric artery & vein (on right to artery). – Jejunal & ileal branches of Superior Mesenteric Artery. – Lymphatics (lacteals). – Lymph nodes (100-200 in number). – Autonomic nerves. – Fat & connective tissue.
- 26. TRANSVERSE MESOCOLON • Broad & horizontal fold of peritoneum. • Suspends the transverse colon from the posterior abdominal wall. • Line of attachment of root of transverse mesocolon: – From right to left it is attached to the anterior aspect of the head and anterior border of the body of pancreas.
- 27. SIGMOID MESOCOLON • Triangular fold of peritoneum. • Suspends the sigmoid colon from the pelvic wall. • Its root is attached in the form of inverted letter ‘V’. • Apex of ‘V’ lies at the bifurcation of left common iliac artery. • At the apex the left ureter lies.
- 28. FALCIFORM (SICKLE SHAPED) LIGAMENT • Sickle shaped fold of peritoneum. • Connects the anterior and superior surface of the liver to the supraumbilical part of the anterior abdominal wall and also to the inferior surface of the diaphragm. • Inferior margin is concave and contains ligamentum teres hepatis. • ligamentum teres hepatis = obliterated left umbilical vein.
- 29. CONTENTS OF FALCIFORM LIGAMENT • Ligamentum teres hepatis. • Paraumbilical veins, tributaries of portal vein. • Numerous small veins which connect paraumbilical vein with the diaphragmatic veins.
- 30. PERITONITS • Peritonitis refers to 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.
- 31. PERITONEAL DIALYSIS • Peritoneum is a semipermeable membrane. • It lies over the blood and lymphatic capillary beds. • Diffusible solutes and water are exchanged b/w the blood and the peritoneal cavity. • Peritoneal dialysis is a procedure by which waste material such as excess urea is removed from the blood in patients with renal failure.
- 32. PERITONEAL CAVITY • Potential space b/w the parietal & visceral pleura. • Subdivisions: 1.) Greater sac- larger compartment, extends across the whole abdomen. 2.) Lesser sac/(Omental bursa)- smaller compartment, lies behind the stomach, liver and lesser omentum. Both sacs communicate with each other through the epiploic foramen (foramen of winslow).
- 34. SUBCOMPARTMENTS OF GREATER SAC Supracolic compartment: • Antero-superior in position. • Surrounds the liver, stomach, spleen and the superior part of the duodenum. • Lies anterior to the pancreas, duodenum, kidney and suprarenal glands.
- 35. Infracolic compartment: • Postero-inferior in position. • Filled with coils of small intestine. • Surrounded by ascending, transverse and descending colons. • Below the transverse mesocolon the compartment is divided into right and left infracolic spaces by the root of mesentery of small intestine.
- 36. INFRACOLIC SPACES Right infracolic space: Triangular outline. Apex at the ileocaecal junction. Bounded by on right by ascending colon. Above by transverse mesocolon. On left by the root of mesentery.
- 37. Left infracolic space: Larger than right. Quadrangular outline. Bounded on- – Above by transverse mesocolon. – Right by the root of mesentery. – Left by the descending colon. – Below continuous with the pelvic cavity.
- 38. PARACOLIC GUTTERS Right paracolic gutter: Lateral to the ascending colon. Continuous above with the hepatorenal pouch. Continuous below with the pelvic cavity. It may be infected by- – Downward spread of infection from the Morrison’s pouch. – Upward spread of infection from the appendix.
- 39. Left paracolic gutter: Lateral to the descending colon. Bounded above by the phrenicocolic ligament. Below continuous with the pelvic cavity. May be infected by an upward spread of infection from the pelvis.
- 40. SUBPHRENIC SPACES • Below the diaphragm there are 6 spaces. • These spaces are related to the periphery of liver. • Important for surgeons as pus often collects in these spaces. • These pus filled spaces thus form the subphrenic abscesses. • Three spaces are on the right side while the other three are on the left side. • One on each side is extra-peritoneal while the other two are intra-peritoneal.
- 41. Subphrenic spaces are named as follows: 1.) Right posterior intraperitoneal compartment. 2.) Right anterior intraperitoneal compartment. 3.) Right extraperitoneal compartment. 4.) Left posterior intraperitoneal compartment. 5.) Left anterior intraperitoneal compartment. 6.) Left extraperitoneal compartment.
- 42. 1 2 3 4 5
- 43. RIGHT POSTERIOR INTRAPERITONEAL COMPARTMENT Also known as ‘hepatorenal pouch’ or the Morrison’s pouch. Boundaries: Anterior- postero-inferior surface of liver. Posterior- peritoneum over the front of upper pole of right kidney and the diaphragm. Above- inferior layer of the coronary ligament. Below- transverse colon and mesocolon.
- 44. HEPATORENAL POUCH OF MORRISON
- 45. COMMUNICATIONS OF MORRISON’S POUCH On the left it communicates with the lesser sac through the epiploic foramen. Along the sharp inferior border of the liver it communicates with the right anterior intraperitoneal compartment.
- 46. CLINICAL SIGNIFICANCE • Most dependent part of the peritoneal cavity in the supine position.
- 47. RIGHT ANTERIOR INTRAPERITONEAL COMPARTMENT • Situated b/w the anterior surface of the right lobe of the liver and the diaphragm. • Boundaries: Anterior- diaphragm and anterior abdominal wall. Posterior- anterior surface of the liver. Superior- superior layer of the coronary ligament. Left- right side of the falciform ligament. Right- communicates with the right posterior intraperitoneal compartment. Below- open.
- 49. RIGHT EXTRAPERITONEAL COMPARTMENT • Space b/w the bare area of liver and the diaphragm. • Boundaries: • Anterior- superior layer of coronary lig. • Posterior- inferior layer of coronary lig. • Left- IVC. • Right- fusion of two layers of coronary ligaments. • Above- diaphragm. • Below- posterior surface of the liver.
- 51. LEFT POSTERIOR INTRAPERITONEAL COMPARTMENT Also k/a the lesser sac or the ‘omental bursa’. It is an extension of the peritoneal cavity. Lies behind the stomach. Communicates with the greater sac through ‘foramen of Winslow’ or the epiploic foramen. Its looks like an empty ‘hot water bottle’. The neck of the bottle is facing towards the right side.
- 52. LESSER SAC or the ‘omental bursa’
- 53. BOUNDARIES OF LESSER SAC Anterior wall: from above downwards- – Caudate lobe of liver. – Lesser omentum. – Posteroinferior surface of the stomach & – Anterior two layers of the greater omentum.
- 54. BOUNDARIES OF LESSER SAC Posterior wall: from below upwards- – Posterior two layers of the greater omentum. – Transverse colon. – Transverse mesocolon. – Pancreas. – Upper part of the left kidney and left suprarenal gland. – Diaphragm.
- 55. RECESSES OF LESSER SAC 1.) Superior recess: lies behind the lesser omentum and the liver. Vestibule of the lesser sac: part of superior recess behind the lesser omentum. 2.) Inferior recess: lies b/w the anterior two and posterior two layers of the greater omentum. 3.) Splenic recess: lies b/w the gastrosplenic and lienorenal ligaments.
- 56. CLINICAL SIGNIFICANCE • Pseudocyst of the pancreas: a collection of fluid in the lesser sac occurs as a result of acute pancreatitis or sometimes after pancreatic injury. • Perforation of posterior wall of stomach spills its contents into the lesser sac.
- 57. EPIPLOIC FORAMEN Situated behind the right free margin of the lesser omentum at the level of T12 vertebra. Communicating passage b/w greater and lesser sac.
- 58. BOUNDARIES OF EPIPLOIC FORAMEN Anterior- right free border of lesser omentum. Posterior- inferior vena cava. Superior- caudate process of the caudate lobe of liver. Inferior- 1st part of the duodenum.
- 59. CLINICAL SIGNIFICANCE Internal hernia: sometimes the loops of small intestine may herniate into the lesser sac through the epiploic foramen. Control of hemorrhage during cholecystectomy: Hemorrhage can be stopped by compressing the hepatic artery in the right free margin of the lesser omentum b/w the thumb & the index finger = Pringle maneuver.
- 60. RECTOUTERINE POUCH OF DOUGLAS Pouch of peritoneum b/w rectum and uterus. Most dependent part of peritoneal cavity in upright position.
- 61. BOUNDARIES OF POUCH OF DOUGLAS Anteriorly: uterus and upper 1/3rd of vagina. Posteriorly: rectum. Inferiorly: the rectovaginal fold of peritoneum.
- 62. CLINICAL SIGNIFICANCE • The pus that gets collected in this pouch can be drained through the posterior wall of vagina= Posterior colpotomy.
- 63. DUODENAL RECESSES In the region of duodeno- jejunal junction, small pocket like pouches of peritoneum are present k/a duodenal recesses. These are sometimes responsible for strangulated retroperitoneal hernia.
- 64. 1. Superior duodenal recess: lies to the left upper end of the 4th part of the duodenum, with its mouth looking downward. 2. Inferior duodenal recess: lies below the superior recess with its orifice looking upward. 3. Paraduodenal recess: lies to the left of the 4th part of the duodenum with its orifice facing medially. The paraduodenal fold contains inferior mesenteric vein in its free border edge. 4. Retroduodenal recess: largest duodenal recesses, lies behind the 3rd and 4th parts of the duodenum. Its orifice looks downward and to the left.