The peritoneum

General features The peritoneum is a thin serous membrane that line the walls of the abdominal and pelvic cavities and cover the organs within these cavities Parietal peritoneum －lines the walls of the abdominal and pelvic cavities Visceral peritoneum －covers the organs Peritoneal cavity －the potential space between the parietal and visceral layer of peritoneum, in the male, is a closed sac, but in the female, there is a communication with the exterior through the uterine tubes, the uterus, and the vagina

Function Secretes a lubricating serous fluid that continuously moistens the associated organs Absorb Support viscera

The relationship between viscera and peritoneum Intraperitoneal viscera －viscera completely surrounded by peritoneum, example, stomach, superior part of duodenum, jejunum, ileum, cecum, vermiform appendix, transverse and sigmoid colons, spleen and ovary Interperitoneal viscera －most part of viscera surrounded by peritoneum, example, liver, gallbladder, ascending and descending colon, upper part of rectum, urinary bladder and uterus Retroperitoneal viscera －some organs lie on the posterior abdominal wall and are covered by peritoneum on their anterior surfaces only, example, kidney, suprarenal gland, pancreas, descending and horizontal parts of duodenum, middle and lower parts of rectum, and ureter Intraperitoneal viscera Interperitoneal viscera Retroperitoneal viscera

Interperitoneal viscera

Structures which are formed by peritoneum Omentum －two-layered fold of peritoneum that extends from stomach to adjacent organs

Lessor omentum －two-layered fold of peritoneum which extends from porta hepatis to lesser curvature of stomach and superior part of duodenum Hepatogastric ligament －extends from porta hepatis to lesser curvature of stomach Hepatoduodenal ligament Extends from porta hepatis to superior part of duodenum Contains common bile duct, proper hepatic a. and hepatic portal v.

Omental foramen Behind the right border of hepatoduodenal ligament Superior－caudate lobe of liver Inferior－superior part of duodenum Anterior－hepatodudenal ligament Posterior－peritoneum covering the inferior vena cava

Greater omentum －four-layered fold of peritoneum, the anterior two layers descend from the greater curvature of stomach and superior part of duodenum and hangs down like an apron in front of coils of small intestine, and then turns upward and attaches to the transverse colon. If an infection occurs in the intestine, plasma cells formed in the lymph nodes combat the infection and help prevent it from spreading to the peritoneum.

Lessor omentum Greater omentum

Omental bursa Position－situated behind the lesser omentum and stomach Walls Superior－peritoneum which covers the caudate lobe of liver and diaphragm Anterior－formed by lesser omentum, peritoneum of posterior wall of stomach, and anterior two layers of greater omentum Inferior－conjunctive area of anterior and posterior two layers of greater omentum Posterior－formed by posterior two layers of greater omentum, transverse colon and transverse mesocolon, peritoneum covering pancreas, left kidney and suprarenal gland

Left－formed by the spleen, gastrosplenic ligament and splenorenal ligament Right－formed by omental foramen The Omental bursa (lesser sac) communicates with the greater sac through the omental foramen.

Mesenteries or mesocolons－two-layered fold of peritoneum that attach part of the intestines to the posterior abdominal wall

Mesentery －suspends the small intestine from the posterior abdominal wall Broad and a fan-shaped Consists of two peritoneal layers Intestinal border－folded, 7 m long Radix of mesentery 15 cm long Directed obliquely from left side of L2 to in front of right sacroiliac joint

Mesoappendix Triangular mesentery－extends from terminal part of ileum to appendix Appendicular artery runs in free margin of the mesoappendix

Transverse mesocolon －a double fold of peritoneum which connects the transverse colon to the posterior abdominal wall Sigmoid mesocolon －inverted V-shaped, with apex located in front of left ureter and division of common iliac artery

Ligaments Ligaments of liver －two-layered folds of peritoneum that attached the lesser mobile solid visera to the abdominal wall Ligaments of liver Falciform ligament of liver Consists of double peritoneal layer Extends from anterior abdominal wall (umbilicus) to live Free border of ligament site of ligamentum teres

Coronary ligament －the area between upper and lower parts of the coronary ligament is the bare area of live, this area is devoid of peritoneum and lies in contract with the diaphragm Left and right triangular ligaments －formed by right extremity of coronary ligament and left leaf of falciform ligament, respectively

Hepatogastric ligament Hepatoduodenal ligament Ligamentum teres hepatis

Ligaments of spleen Gastrosplenic ligament －a double layer of peritoneum that connects the fundus of stomach to hilum of spleen. In this double layer of peritoneum are the short gastric and left gastroepiploic vessels Splenorenal ligament －extends between the hilum of spleen and anterior aspect of left kidney. The splenic vessels lies within this ligament, as well as the tail of pancreas Phrenicosplenic ligament Splenocolic ligament

Ligaments of stomach Hepatogastric ligament Gastrosplenic ligament Gastrophrenic ligament Gastrocolic ligament Gastropancrestic ligament

Folds and recesses of posterior abdominal wall Superior duodenal fold and recess Inferior duodenal fold and recess Intersigmoid recess －formed by the inverted V attachment of sigmoid mesocolon

Retrocecal recess －in which the appendix frequenty lies Hepatorenal recess －lies between the right lobe of liver, right kidney, and right colic flexure, and is the lowest parts of the peritoneal cavity when the subject is supine

Folds and fossas of anterior abdominal wall Medial umbilical fold －contain the remnant of urachus (median umbilical ligaments) Medial umbilical fold －contains remnants of the umbilical arteries (medial umbilical ligaments) Lateral umbilical fold －contains the inferior epigastric vessels Supravesical fossa Medial inguinal fossa Lateral inguinal fossa

Pouches In male－rectovesical pouch In female Rectouterine pouch －between rectum and uterus Vesicouterine pouch －between bladder and uterus

Peritoneal subdivisions The transverse colon and transverse mesocolon divides the greater sac into supracolic and infracolic compartments. Supracolic compartments (subphrenic space)－lies between diaphragm and transverse colon and transverse mesocolon Suprahepatic recess lies between the diaphragm and live－the falciform ligament divides it into right and left suprahepatic recesses

Left suprahepatic recesses left anterior suprahepatic spaces left posterior suprahepatic spaces Right suprahepatic recesses right anterior suprahepatic spaces right posterior suprahepatic spaces bare area of live (extraperitoneal space)

Infrahepatic recess lies between the live and transverse colon and transverse mesocolon－the ligamentum teres hepatic divides it into right and left infrahepatic recesses Right infrahepatic recesses (hepatorenal recess) Left infrahepatic recesses left anterior infrahepatic space left posterior infrahepatic space

Infracolic compartments －lies below the transverse colon and transverse mesocolon Right paracolic sulcus (gutter) －lies lateral to the ascending colon. It communicates with the hepatorenal recess and the pelvic cavity. It provides a route for the spread of infection between the pelvic and the upper abdominal region. Left paracolic sulcus (gutter) －lies lateral to the descending colon. It is separated from the area around the spleen by the phrenicocolic ligament, a fold of peritoneum that passes from the colic flexure to the diaphragm.

Right mesenteric sinus －triangular space, lies between root of mesentery, ascending colon, right 2/3 of transverse colon and transverse mesocolon Left mesenteric sinus －lies between root of mesentery, descending colon, right 1/3 of transverse colon and transverse mesocolon, its widens below where it is continuous with the cavity of the pelvis

Supracolic region

abdominal part of esophagus stomach duodenum liver Extrahepatic Biliary Apparatus spleen pancreas

Abdominal aorta Continuation of thoracic aorta at aortic hiatus of diaphragm in front of T12 Terminates at lower border of L4 vertebra by dividing into right and left common iliac arteries

Parietal branches Inferior phrenic a. (one pair) Lumbar a. (four pairs of arteries that supply the posterior abdominal wall) Median sacral a.

Visceral branches Paired branches Middle suprarenal artery Testicular (ovarian) artery

Unpaired branches Celiac trunk －a short thick vessel that arises from the front of aorta, at the level of T12 Superior mesenteric a. －arises from the front of aorta, at the level of L2 Inferior mesenteric a. －arises from the front of aorta, at level of L3

Celiac trunk Left gastric a. Left branch Right branch Short gastric a. Common hepatic a. Cystic a. Splenic a. Right gastric a. Splemic branches Proper hepatic a. Gastroduodenal a. Left gastrioeploic a. Superior pancreaticoduodenal a. Right gastroepiploic a.

Celiac trunk

Superior mesenteric a. Superior Middle colic a. Mesenteric v. Inf. pancresticodudenal a. Superior mesenteric a. Right colic a. Jejunal and ileal a. Ileocolic a. Appendicular a.

Inferior mesenteric a. Inferior mesenteric v. Left colic a. Sigmoid a. Superior rectal a.

Colic marginal artery

Relations of abdominal aorta Anteriorly (from above downward) Pancreas Ascending part of duodenum Radix of mesentery Posteriorly Upper four lumber vertebrae On its right Inferior vena cava On its left Left sympathetic trunk

Veins of abdomen and pelvis Internal iliac vein Parietal tributaries: accompany with arteries Visceral tributaries →superior rectal vein→inferior mesenteric v. ①Rectal venous plexus →inferior rectal vein→internal iliac v. →anal vein→internal pudendal v. ②Vesical venous plexus →vesical v. ③Uterine venous plexus →uterine v.

External iliac vein– accompany the artery Common iliac vein– formed by union of internal and external iliac veins in front of sacroiliac joint, end upon L4~L5 by uniting each other to form inferior vena cava

Inferior vena cava Formed by union of two common iliac veins anterior to and just to the right of L4~L5 Ascends on the right side of aorta, pierces vena cava foramen of diaphragm opposite the T8 and drains into the right atrium Conveys blood from the whole body below the diaphragm to the right atrium

Chief tributaries Parietal Visceral Paired inferior phrenic v. paired lumbar v. (four) Visceral Right and left renal veins Right suprarenal vein (left drain into left renal vein) Right testicular or ovarian v. (left drain into left renal vein) Hepatic veins : right, left and intermediate

Relations of inferior vena cava Anteriorly (cranially to caudally) Liver Head of pancreas Horizontal part of duodenum Right testicular (or ovarian) a. Radix of mesentery Posteriorly Right crus of diaphragm Upper four lumber vertebrae Left sympathetic trunk Parietal branches of abdominal aorta On its right Psoas major Right kidney Right suprarenal gland On its left Abdominal aorta

Hepatic portal vein General features Formed behind the neck of pancreas by the union of superior mesenteric vein and splenic vein Ascends upwards and to the right, posterior to the first part of duodenum and then enters the lesser omentum to the porta hepatis, where it divides into right and left branches There are no functioning valves in hepatic portal system Drains blood from gastrointestinal tract from the lower end of oesophagus to the upper end of anal canal, pancreas, gall bladder, bile ducts and spleen

Variation and anomalies of hepatic portal vein

Tributaries of hepatic portal vein 1. Superior mesenteric v. 2. Inferior mesenteric v. 3. Splenic v. 4. Left gastric v. 5. Right gastric v. 6. Cystic v. 7. Paraumbilical v.

Portal-systemic anastomoses 1. At the lower end of the oesophagus Hepatic portal vein → left gastric vein → esophageal venous plexus → esophageal vein → azygos vein → superiorvena cava 2. At rectal venous plexus Hepatic portal vein → splenic vein → inferior mesenteric vein → superior rectal vein → rectal venous plexus → inferior rectal and anal veins → internal iliac vein → inferior vena cava 3. At periumbilical venous plexus Hepatic portal vein→paraumbilical vein→periumbilical venous plexus→ thoracoepigastric and superior epigastric vein → superiorvena cava superficial epigastric and inferior epigastric veins → inferior vena cava

4. Portal-retroperitoneal anastomosis Between the retroperitoneal branches of the colic veins and the lumbar veins, pancreaticoduodenal veins with the renal veins and the subcapsular veins of the liver with the phrenic veins twigs of colic veins (portal) anastomosing with systemic retroperitoneal veins

The lymphatic drainage of abdomen Lymphatic drainage of abdominal wall To axillary lymph node from region above umbilicus To superficial inguinal lymph node from region below umbilicus To lumbar lymph node from post wall of abdomen

Lymphatic drainage of abdominal viscera Lumbar lymph nodes Lie on posterior abdominal wall, along the abdominal aorta and inferior vena cava Receive lymph from kidneys, suprarenal glands, testes, ovaris, fundus of uterus, ovary, and common iliac nodes Right and left lumbar trunks formed by efferent vessel Paired viscera－drain to the lumbar lymph nodes

Celiac lymph nodes －situated around the celiac trunk Superior mesenteric lymph node －situated around superior mesenteric a. Inferior mesenteric lymph node －situated around inferior mesenteric a. Intestinal trunk －formed by efferent vessel of celiac, superior and inferior lymph nodes

Thoracic duct Begins in front of L1 as a dilated sac, the cisterna chyli, which formed by joining of left and right lumbar trunks and intestinal trunk Enter thoracic cavity by passing through the aortic hiatus of the diaphragm and ascends along on the front of the vertebral column, between thoracic aorta and azygos vein Travels upward, veering to the left at the level of T5 At the roof of the neck, it turns laterally and arches forwards and descends to enter the left venous angle Just before termination, it receives the left jugular, subclavian and bronchomediastinal trunks Drains lymph from lower limbs, pelvic cavity, abdominal cavity, left side of thorax, and left side of the head, neck and left upper limb

Spleen Location: lies in the left hypochondriac region (between stomach and diaphragm) deep to the 9th to 11th rib, its long axis corresponds roughly to the 10th rib Shape－reddish in colour

Two surfaces Diaphragmatic: smooth, convex Visceral: concave, hilum of spleen Two extremities Anterior－wider Posterior－rounder Two border Superior－has 2-3 splenic notch, which serve as a landmark on palpation when it is enlarge; normally it is not palpable Inferior－rounder Functions: the spleen is considered to be important in: Formation of lymphocytes and monocyte Phagocytosis of bacteria, inert particles and white blood cells and platelets Destroying effete or abnormal red blood cells Making antibodies

Spleen Function Erythrocyte storage Phagocytosis Cytopoiesis Immune responses

Relationships of spleen Diaphragmatic surface－diaphragm Visceral surface Anteriorly－fundus of stomach Posteriorly－left suprarenal gland and kidney Inferiorly－tail of pancreas and left colic flexure