 Good day everybody. Dr. Sanjo Sanyal, professor department chair. In an earlier dissection we had mentioned the structures of the liver as it was located under the right dome of the diaphragm. We are continuing from there. Now we have completely eviscerated the liver. So just to bring up to speed, this is the anatomical right lobe of the liver. This is the anatomical left lobe of the liver. This is the falciform ligament on the free margin of the falciform ligament. This is the round ligament of the liver. This is the anterior superior surface of the liver which was under the right dome of the diaphragm. This is the posterior inferior surface of the liver which is the visceral surface of the liver. This is located under the right dome of the diaphragm and now that we have removed it we can see this portion of the liver here. This is the bare area of the liver. To trace the falciform ligament we can see that the falciform ligament as it comes towards the diaphragm it splits into a left leaf and a right leaf. In between anterior layer of the coronary ligament and the posterior layer of the coronary ligament we have the bare area of the liver and passing through the bare area of the liver we have the opening for the inferior vena cava. The two leaves of the coronary ligament fuse on the left side to form the left triangular ligament which we can see here. Similarly they will fuse on the right side to form the right triangular ligament which we have removed already. Now let's we turn the liver a little bit. This is the on the inferior border of the liver and this is the one we separate the anterior superior surface of the diaphragmatic surface from the visceral or the posterior inferior surface. We can see some of the rib markings here. The liver is related to the seventh to the eleventh ribs on the right side. So therefore any injury to the ribs seventh to the eleventh on the right side can potentially cause rupture of the right anatomical lobe of the liver. Let's come to the relationships of the visceral surface of the liver. Starting from left to the right we have the isophagus, the stomach, the pylorus, then we have the diodenum, the right kidney, right supra-egional. So these are the structures which are related. Also related to the inferior border of the liver is the transverse colon. Now I have turned the liver and we can see this is the region of the portahepatus and in this particular cadaver we have already made a separate video to show the widely separated out portahepatus with the three structures of the extra hepatic portal triad. These are the hepatic artery, the portal vein and the common bile duct. This is the fossa for the gallbladder and we can see the gallbladder is attached here and it is covered by peritoneum on all aspects except the surface which is attached to the liver and this is the cystic duct coming from the gallbladder. This is the inferior vena cava which I have already mentioned. We can see the inferior vena cava opening and I'll put my instrument here and we will be able to see it coming out from the other side. This is the inferior vena cava. So therefore this is the fissure for the inferior vena cava. If we were to consider the fissure for the inferior vena cava and the fossa for the gallbladder, this corresponds to right sagittal fissure. It is broken up into two components by this portion of the liver. This is known as the caudate process of the liver. This is the caudate lobe of the liver and this is the papillary process of the liver. If you were to look to the left we see yet another fissure here. This is the fissure for the round ligament of liver and we can see the round ligament of the liver located here which is the remnant of the umbilical vein in fetal life. You can see the remnant of the phasiform ligament here and the continuation of the fissure for the round ligament is this fissure here. This is the fissure for the ligament of venosa which is the remnant of the ductus venosis which shunts oxygenated blood from the umbilical vein directly to the inferior vena cava by passing the liver in embryonic life. So therefore this whole continuous fissure is called the left sagittal fissure. Having mentioned these two fissures now we can look at the surgical segments of the liver. If we were to draw a line joining the gallbladder fossa and the inferior vena cava which I had mentioned was the right sagittal fissure. This actually corresponds to the main portal fissure. On the diaphragmatic surface the main portal fissure is indicated by an imaginary line which extends from the opening of the inferior vena cava cross the diaphragmatic surface like this to the tip of the gallbladder and this line is called the cantile line. So if we were to take a section through this cantile line this corresponds to the main portal fissure and inside this main portal fissure will be located the middle hepatic vein and this is the one which divides the liver into a right surgical segment and a left surgical segment. Then we come to this left sagittal fissure that comes to be known as the left portal fissure or the umbilical fissure. If we were to cut through this this will show us the left hepatic vein. This fissure divides the left surgical lobe into two parts a right part and a left part. Similarly there is yet another imaginary line to the right of cantile line and that is somewhere sheared and if we were to cut through that that will give us the right hepatic vein and that imaginary line where there is no fissure divides the right surgical lobe into a right part and a left part. So these are the ways of surgically subdividing the liver and subsequently if we were to take a transfer section through the liver we will divide the lobe into eight hepatic segments. So this is how the segments of the liver are demarcated and in the surgical segments which are numbered by Roman numerals 1 to 8 the caudate lobe of the liver is given Roman numeral number one surgical segment number one and this portion of the liver which is between the fissure for the round ligament and the gallbladder fossa this is known as the quadrate lobe of the liver. This is part of hepatic segment number four. Let me just quickly give you a recap though I made a separate video to show you the portahepatus. Portahepatus we have highly stretched it out this is the region where all the structures enter or leave the liver and what do we see here? The portahepatus is bereft of peritoneum. Peritoneum is attached only to the margins of the portahepatus and that is the hepatodeutonal ligament and running into the portahepatus are these three structures this is the hepatic artery proper this is the portal vein and this is the common bile duct. We have separated them out widely and they are all enclosed in the hepatodeutonal ligament which is attached to the margins of the portahepatus and we can see the structures entering into the portahepatus. Before I conclude I wanted to tell you something about the gallbladder os. As we have mentioned the gallbladders look at in the gallbladder fossa. We have purposely not removed the gallbladder because that will completely remove it from the liver itself. This is the fundus of the gallbladder which is projecting from the inferior border of the liver and this is the only portion of the gallbladder which is completely covered by visor peritoneum. The rest of the gallbladder is stuck to the gallbladder fossa and therefore it is covered by peritoneum only on its inferior surface. Therefore if we were to remove it from here this very portion of the gallbladder will be free from peritoneum and that is the gallbladder fossa. In 0.5% of cases there may be a small cholecystohepatic duct directly connecting the liver surface to the gallbladder. Rest of this is the gaudy of the gallbladder and then we have the neck of the gallbladder continuing as the cystic duct. The cystic duct forms a slight curve in this like this. In this particular case the cystic duct is very long and it is opening what is called a low opening of the cystic duct into the common hepatic duct to form the common bile duct. So therefore this triangular space bounded by the cystic duct on one side, common hepatic duct on the other side and the surface of the liver above this is referred to as the callot strangle and the most important content of the callot strangle is this artery here. This is the cystic artery accompanied by the two cystic veins and cystic lymph node. So this is the place where we do surgery when we have to do a cholecystectomy and I've already mentioned all the anatomical variations in another dissection. The gallbladder is located very close to the first part of the duodenum and to the transverse colon. So therefore if there's a stone inside the gallbladder and if it is neglected it can potentially perforate into the duodenum or to the transverse colon forming respectively a cholecystodurnal and a cholecystocolic fistula. A cholecystodurnal fistula can lead to gallstone alias. These are the structures which I wanted to show you in this dissection of the liver. Thank you very much for watching. Dr. Sanjay Sanyal signing out. Who is the camera person? If you have any questions or comments please put them in the comment section below. Have a nice day.