Tracing the peritoneum in sections – simplified

now I’m going to deal with the peritoneum in a sagittal section of the trunk let’s first of all draw the trunk I will start from the pelvis from the area that is in front of the pubic symphysis this is the anterior abdominal wall and the diaphragm here the rock abdominal diaphragm now the posterior abdominal wall lumbar region and the sacral region now let’s put some of the viscera in here first of all I will put the liver diaphragmatic and visceral this is the visceral surface of the river returning back to the diaphragmatic surface of the liver and then here is the stomach the wall of the stomach I will put some roogie here to indicate that it’s a stomach then the colon this is the transverse colon actually and on the posterior abdominal wall I’ll draw the pancreas and then I’ll draw the small intestine a piece a loop of small intestine here then let’s put some of them pelvic viscera here we have the rectum and anal canal and this is a female subject so I’ll draw the uterus and vagina this is a posterior vaginal fornix here and then T really is the urethra and the you’re a very bladder in front of the pubic symphysis now let’s sketch the peritoneum the peritoneum first of all we should remember that the peritoneum is divided into visceral and parietal peritoneum layers and these layers are continuous with each other so it is a single sheet peritoneum parietal and visceral layer of peritoneum the parietal layer of peritoneum is related to the varieties or the walls and the visceral layer is related to the viscera but they are continuous with each other the cavity of the peritoneum is a potential space that is located between the visceral and parietal layers of the peritoneum it’s a very thin space a potential space that is located between these two layers I’ll draw the parietal peritoneum in blue so I will start in the region at the anterior abdominal wall that is probably close to the umbilicus go up this is parietal peritoneum of the anterior abdominal wall and then the peritoneum lines the diaphragm and reflected from the diaphragm to the diaphragmatic surface of the liver here as it is reflected on the liver it will form the visceral peritoneum so I will change the color into pink and this is the visceral peritoneum now covering the liver the diaphragmatic surface of the liver and then it is reflected on the visceral surface of the liver here close to the hilum of the liver it will be reflected as the interior layer of the lesser omentum between the liver and the lesser curvature of the stomach this is the stomach and then passing on the anterior surface of the stomach to the greater curvature of the stomach and then reflected from the greater curvature of the stomach as the greater omentum so this is the anterior layer of the greater omentum the greater omentum is a double layer and it will be reflected backwards towards the transverse column so it passes around the transverse colon peritoneum the visceral peritoneum and then reflected from the transverse colon to the posterior abdominal wall where it reaches the site of the pancreas this reflection is called the transverse MS o : then it covers the pancreas the post of the pancreas is a literal peritoneum structure it has no misandry unlike that for example here we have the transverse colon transmission 3 this is the piece of peritoneum that extended from the transverse colon to the posterior abdominal wall and then as this peritoneum covers the pancreas is still visceral peritoneum but as it reaches the posterior abdominal wall now it becomes the parietal peritoneum so I’m going to continue it in blue covering the posterior abdominal wall and then reflected from the posterior abdominal wall at the left of the transverse process of l2 vertebra it

will be reflected as the mesentery of the small intestine now it should be visceral peritoneum so this is a visceral peritoneum as a double fault of visceral peritoneum it encloses the small intestine and this is a loop of small intestine representing that and returns back has a double fold of peritoneum to the posterior abdominal wall so this is the mesentery of the small intestine now at this point it will come back to be a parietal peritoneum and so I am going to draw it in blue and continues as the parietal peritoneum of the posterior abdominal wall then on to the pelvis and as it reaches the rectum it will be reflected in the front of the rectum the rectum has no mass entry the peritoneum will be reflected as a visceral peritoneum in front of the rectum then dips into a pouch that is reflected from the rectum onto the posterior vaginal fornix and then onto the posterior wall of the uterus this is the rectal uterine pouch or the pouch of Douglas in the male it is reflected directly on to the urinary bladder and is called the rectal recycle pouch but in the female it is reflected onto the posterior vaginal for mix and the posterior wall of the uterus it covers the entire posterior wall of the uterus reflected onto the fundus and then the anterior wall of the uterus about upper two-thirds and reflected on the urinary bladder upper surface of the urinary bladder creating another pouch here and that is the user of a cycle pouch this pouch is not present in the male because in the male there is no vagina and uterus intervening between the rectum and the urinary bladder and here the peritoneum will be reflected back to the anterior abdominal wall becoming parietal peritoneum I am going to change the color into blue so this is the parietal peritoneum reflected onto the anterior abdominal wall and returning back as the parietal peritoneum of the anterior abdominal wall into the point where we first started we’ve started here approximately at the level of the umbilicus so you can see here that the peritoneum is a continuous layer it’s a continuous sheet and where it lines the walls it is called parietal where it covers the viscera it is called the visceral the peritoneal cavity is a continuous cavity from the abdomen into the pelvis and this cavity is located between the visceral and parietal layers of peritoneum it is exaggerated here in this diagram otherwise it is a potential space and the two layers are in many places they are opposed to each other and where there is a double layer of peritoneum as we see here in the small intestine it is called mason tree sometimes it’s called ligaments sometimes it’s called omentum like here in the lesser omentum and the greater omentum now let’s continue this diagram because here this sack this / part of the peritoneal cavity here this is called the greater sac and there is another sac which is located behind mainly behind the stomach behind the liver and extends a little bit into the greater omentum this is called the lesser sac so let me draw the a lesser sac this is again a visceral peritoneum covering the liver and then the visceral surface of the liver will be reflected on to the lesser curvature of the stomach creating a double fault with the fault that we have just drawn earlier and then on the back of the stomach returning into the greater curvature of the stomach and this continues as a fault double fault with the fault that we have just the drone of the greater omentum and returns back to enclose the transverse colon and reflected backwards to the posterior abdominal wall as the transverse miss your : until it reaches the pancreas which is retroperitoneal structure now it will be become a parietal peritoneum so I change the color into blue and that is the parietal peritoneum returning back to the same point this creates a

sac as a lesser sac or we call it the omentum versa that is located behind the stomach at the beginning this I mean umbria logically speaking this sac was not present but because of the folding of the gut and because of mainly of the rotation of the stomach then this diverticulum or recess will be created behind the stomach and this recess communicates with the greater sac through an opening this is the approximate site of the opening it is said to be located in the free border of the restaurant mentum and is called the fe fluid foramen or the foramen of wind slope it represents the only communication between the greater sac and lesser sac this this arrow here goes from the greater sack into the lesser sac through the epiploic foramen and this is the only natural communication between the two otherwise in order to access the lesser sac you have to either cut or incise the lesser omentum or you can cut or in size this part of the greater omentum that extends between the greater curvature of the stomach and the transverse colon that is called the ghost gastrocolic omentum or you can in size or cut this double fold of peritoneum here between the transverse colon and the pancreas which is the transverse means your colon but keep in mind that all these peritoneum folds are vascular folds and so they contain blood vessels also I want you to notice the extension of the lesser sac into the greater omentum in life this extension of the lesser sac into the greater omentum is obligated so the gastrocolic omentum is fusing with the anterior surface of the colon and these faults are brought together instead of having four layers that will become double layers and the lesser sac is confined to the area that is behind the stomach and behind the liver also I want you to notice here that the liver is not completely covered by peritoneum as you can see here and that there is an area here in the river that is the bare area of the river it is called where deliver is in direct contact with the diaphragm and this area is located between two folds of peritoneum that are called the coronary ligament so this is the superior and inferior layers of the coronary element also note that the viscera are not located inside the peritoneal cavity they are almost completely covered by peritoneum but they are not inside the peritoneal cavity the peritoneal cavity as I mentioned in the form of a greater shock or the lesser sac is a thin space potential space and does not contain these viscera but the viscera are almost completely covered by peritoneum and these viscera that are almost completely by peritoneum and usually they have a double fold of peritoneum suspending them like the stomach here are called intraperitoneal so an intraperitoneal structure is not does not mean that is located inside the peritoneal cavity but almost completely covered by peritoneum again here the transverse colon is almost completely covered by peritoneum the small intestine is almost completely covered by peritoneum and has misandry so it is intraperitoneal while if we look at the pancreas for example it doesn’t have a mission tree and it has a area that is not covered by peritoneum and so it is a retro peritoneum structure and in fact most of the pancreas is retroperitoneal structure except for the tail of the pancreas also look at the rectum the electrum has no Mason tree it’s covered by peritoneum either anteriorly or anteriorly and laterally so it is retro peritoneum here I want you to notice that the peritoneum again the peritoneum of the abdomen is continuous with that of the pelvis and you can see here the peritoneum is as if this is draped over pelvic viscera which are located outside the peritoneum this is an important relation here the posterior vaginal formics which is related to the peritoneum this is the only part of the vagina that is related to the peritoneum the urinary bladder has its superior surface only

the superior surface of the urinary bladder and the female is related to the peritoneum now let me follow the peritoneum in a horizontal section almost at the level of t12 vertebra I will arrange the viscera so that the section looks similar to the axial CT or MRI section because it will be more familiar with these sections better than displaying them in an anatomical section in other words I will draw the section so that as if you are looking at the section of the body from below so this is the liver visceral surface of the liver here now let me draw the stomach this is a section on the stomach showing the part of the body and this represents the roogie the wrong decision or Falls of the mucosa of the stomach here the rookie leads into the pyloric sphincter pylori canal also on the left side of the body the other viscous is the spleen so this is the spleen here and plussed up to the posterior abdominal wall are the kidneys and section they look oval in shape this is the left kidney and here is the right kidney so to make look better I will try to draw the vertebra this is supposed to be t12 vertebra another transverse process on the right side and here is the vertebral canal so in the periphery here it’s the body wall where there are muscles and ribs here because ribs are also related to the liver abdominal viscera liver on the right side and on the left side the ribs are related to the spleen 9 10 and 11th rib are also related to the spleen and here there are muscles of the erector spinae muscle and some muscles of the posterior abdominal wall which I am not going to draw let me put the two major vessels here and the posterior abdominal wall that is the aorta and the inferior vena cava so this is the aorta the aorta is toward the left side so this is the aorta the aorta is toward the left side and here is the inferior vena cava it has thinner wall being a vein and a little bit flattened it’s on the right side then further vena cava now I will draw the parietal peritoneum starting at Susan in blue again starting at a point on the anterior abdominal wall in front of the liver this is the parietal peritoneum of the anterior abdominal wall going back to the posterior abdominal wall until it reaches the site of the kidney and at this point it is going to cover the kidney so it will become a visceral peritoneum growing it in pink covers the kidney and is reflected from the kidney as a fault this is one layer of the fault extending from the kidney into the spleen and this is called the Lyon arena ligament Lyon means the spleen and arena Lyon or in a ligament peritoneum encloses the spleen completely encloses the spleen so the spleen is an intraperitoneal structure and return back to the hilum of the spleen where the playing arena ligament originally was attached this is the region of the hilum of the spleen where vessels pass in and out of the spleen and then it’s going to be reflected into the greater curvature of stock in a double fold of peritoneum this is a one layer of default to the greater curvature of the stomach and this is called the gastro splenic ligament gastro splenic ligament we will notice that all these folds and ligaments they most of them they contain blood vessels and so from the greater curvature of the stomach the visceral peritoneum covers the anterior surface of the stomach and reaches the lesser

curvature of the stomach at the lesser curvature of the stomach it is going to be reflected towards the liver and this fold of peritoneum is called the lesser omentum it has a free border so I am NOT going to attach it here in section directly to the liver because representing it’s a free border so this is the free border here it’s a thick border returning back into the lesser curvature of the stomach and from the lesser curvature of the stomach it covers the posterior surface of the stomach until it reaches the greater curvature and reflected back to the spleen so the visceral peritoneum here on the posterior surface of the stomach would reach the greater curvature of the stomach and will be reflected from here to the hilum of the screen again creating the second layer of the gastro splenic ligaments then they from the hilum of the spleen it will be reflected back onto the kidney creating the second layer of the lion or renal ligament the double fold of peritoneum and then around the kidney the kidney has no mesentery it is a retroperitoneal structure in fact it’s a primary retroperitoneal structure and now the peritoneum will become parietal peritoneum it covers the posterior abdominal wall at this position there is psoas major muscle and then passes in front of the abdominal aorta and inferior vena cava and then reaches the right kidney so when it reaches the right kidney becomes a visceral peritoneum I’ll draw it in pink covering the anterior surface of the kidney the kidney has no mass entry and reaching back to the posterior abdominal wall becoming parietal peritoneum so I’ll draw it again in blue and to the same point where we have just started from this point it’s going to be reflected as a double fold of peritoneum now I’m going to draw one of the Leafs of this double fault and this is the this is the falciform ligament one of the leaves of the falciform ligament extending from the diaphragm entire abdominal wall to deliver and the peritoneum encloses the liver completely surrounds the river here course there is a bare area which is shown in longitudinal section but not in this section this is the visceral peritoneum covering the liver encloses the liver and then this is the second fold or the second leaf of the fault of the falciform ligament returning back so you can see again that the peritoneum is visceral and parietal it is a continuous sheet of peritoneum changing names and having false different faults as we have just seen the falciform ligament the lesser omentum the gastro splenic ligament the lion or inner ligament and it’s a continuous cavity which is actually as I said it’s a potential space but here it has been exaggerated here this is the greater sac of peritoneum and the lesser sac is located behind the stomach and the lesser omentum so this is the lesser omentum and this is the lesser sac it has an opening here which is between the free border of the lesser omentum and the inferior vena cava which is located posteriorly and this opening is the same as this one it is the epic Levesque foramen and this is again the direction of the arrow which passes into the foramen from the Greater sac to the lesser sac and the free border of the Reza remain t’m there are three structures a post either struck which is big and this is the portal vein and then there are two anterior structures one of them I’m going to draw it in green and that is located on the right side and this is the bile duct and the other one I’m going to draw it in red it’s an artery

it is the hepatic artery located on the left side the bile duct is located on the right side both of them are located interior to the portal vein and so the epic lyric forum in here when you pass your finger into the apical foramen and order to enter into the lesser sac your finger will be located between the inferior vena cava posteriorly and the portal vein anteriorly if you go superiorly you’re going to touch the liver and if you go and feel early will touch the first part of the duodenum now let me give you an idea about how the lesser sac is formed we have to go back to embryology I’ll draw the gutta tube the the tube the gut starts as a single tube and this tube start to have dilatations that has some folding but originally it is a single tube so this is the gutter tube here here is a distinction that is going to form the stomach and it is I forgot midgut and hindgut originally the gut is suspended from the posterior abdominal wall by a layer of mesentery which is a dorsal mesentery so this is the dorsal Mason 3 that suspends the whole gutta tube is suspended by this machinery whether forgot midgut or hindgut it’s the dorsal Mason 3 in addition to that there is a ventral Mason tree and this ventral Mason tree is only attached to the foregut anteriorly or ventrally it is attached to the foregut during development the liver grows and the ventral mesentery of the foregut it’s a forged derivative so the river grows here this is where the liver grows and thus it will divide the ventral mesentery into two parts apart that extends between the liver and the diaphragm anterior abdominal wall and this is the falciform ligament and a part that extends between the liver and the stomach and this is the lesser omentum so here you can see that the falciform ligament which stretches from the anterior abdominal wall encloses the liver and is reflected to the stomach and lesser curvature of the stomach as the lesser omentum originally these two layers or these two Falls were a single fault that is the ventral mesentery in addition the spleen grows in the dorsal mason 3 of the 4 guts so this is the region of the screen here it grows in the dorsal mesentery of the for cut and again it divides the dorsal mason tree here into 2 parts apart between the spleen and the stomach and that is the gastric splenic ligament and a part here between the spleen and the posterior abdominal wall where the kidney is going to be formed and this part is called de l’annĂ©e no renal liquor so lion-o renal ligament here and the gastro splenic ligament originally they were the dorsal machinery of the foregut where the spleen started to grow in this region dividing it into two parts now let me show you these details in another diagram to trying to represent the rotation of the foregut rotation of the stomach the stomach actually rotates a 90 degrees so that it’s left surface becomes anterior and it’s right surface becomes posterior now let me use another diagram for further clarification this is the stomach beginning of the do genome this is where the kidney is located on the posterior abdominal wall and now I will draw the peritoneum I will draw it as in one color I’m going to use the green color so here is the peritoneum on the posterior abdominal wall reflected in front of the kidney and then it is reflected from the kidney to the stomach but because the stomach is going to rotate there will be like a recess here then returns the greater curvature of the stomach reflected from the greater curvature to

the lesser curvature of the stomach from the lesser curvature it goes toward the liver and returns back as the lesser omentum and then on the posterior surface of the stomach to the greater curvature and then returning back as a double fault of the dorsal mesentery and the mesentery here in front of the right kidney so this what happens the stomach rotates this is how the stomach rotates it rotates so that the the left surface of the stomach becomes anterior and the right surface of the stomach becomes posterior because the stomach is suspended in a dorsal mason 3 then the dorsal mesentery will become folded and the greater sac will have a diverticulum or a recess behind the stomach and this is called the lesser sac and it has an opening here behind the free border of the lesser omentum this is the free border of the lesser omentum which is shown here to complete the picture let me draw the spleen the spleen will grow in this dorsal mason tree and it will be covered by the peritoneum because it grows within the dorsal mesentery so the peritoneum will come to cover the spleen and therefore we will have two folds here of the dorsal mesentery one of them between the screen and the kidney and that is called the lion or in a ligament and the other between the spleen and the greater curvature of the stomach and fundus of the stomach and this is called the gastric splenic ligaments you