 Everybody, Dr. Sanjo Sanyal, Professor Department Chair. The first part of the dissection will be to demonstrate to you the heart, the morphology of the heart in situ, including the pericardium. So the heart is, as it is located in the pericardial cavity. This is the cut section of the fibrous pericardium. And we have retained some of the portions of the fibrous pericardium just to show you how it looks like and how tough and leathery and how membranous it is. This fibrous pericardium is roughly conical shaped. The apex of the cone is at the junction of the descending aorta with the arch of the aorta. And you can see part of the fibrous pericardium has been retained here. And the base of the cone is the pericardial phrenic ligament, where it is fused with the central tendon of the diaphragm. This is the cut margin of the fibrous pericardium. And inside that is the pericardial cavity, which is actually the serious pericardium, lined by an outer peritoneal layer and an inner visceral layer. The inner visceral layer is actually the one which is covering the heart. And that is also the same as the epicardium of the heart. Now, since we have removed the fibrous pericardium, and we have seen that the fibrous pericardium has fused with the three major vessels, all of which have been cut here. One, it has fused with the ascending aorta. It fuses with the tunic advincia. Here, it has fused with the superior vena cava, which has been cut here. And here, it has fused with the pulmonary trunk. So I'm putting my finger behind the heart. And my finger has gone into oblique pericardial sinus, which is behind the base of the heart. The next important space is transverse pericardial sinus. And for that, my finger will go in front of the superior vena cava. And it'll go behind the ascending aorta and it'll go behind the pulmonary trunk. This is the location of the transverse pericardial sinus. This is the location where the cardiothoracic surgeon pushes finger prior to open-heart surgery when he has to cannulate these greater-grade vessels for the purpose of cardiopulmonary bypass. And if I were to dip my finger down, my finger will stop at the superior border of the heart, which is the lower limit of the transverse pericardial sinus. So these are two important spaces of the pericardial cavity. A quick word about the clinical implications of this pericardial cavity. Any collection inside the pericardial cavity can be damaging to the heart. Like, for example, pericardial effusion, hemopericardium, pyopericardium, all these things can constrict. And if there's a rupture or injury to the heart, then blood can collect rapidly inside the pericardial cavity. And because the fibrous pericardium is so tough, it cannot allow the cavity collection to expand. So instead, it compresses the heart, a condition which is usually fatal unless treated rapidly. And that is called cardiac tamponade. It's a significant pericardial effusion. And it is threatened to compress the heart. We have to do the procedure of aspiration from the pericardial cavity. And that is known as pericardial synthesis. And the approach to the pericardial synthesis is, from the subcostal angle, we have to direct the needle to the left, approximately in this axis. The purpose of doing this is, if I were to remove the chest wall, we notice that on the left side, there is the cardiac notch of the left lung. And in this place, the pericardial pleura moves a little away to the left. Therefore, in this region, the pericardium is a direct contact with the chest wall without any intervening pericardial pleura, the so-called bare area of the pericardium. If we approach it in this direction, we can do a pericardial synthesis without fear of damaging the pleura. So this is the procedure for pericardial synthesis. Now let's take out the heart and show you the morphology of the heart as we can see them. We can see that this is the cut portion of the aorta here. This is the cut portion of the pulmonary trunk here. This is the cut portion of the superior vena kiva. And this is the cut portion of the inferior vena kiva. This is the cut portion of the inferior vena kiva here. This is the cut portion of the superior vena kiva. This is the opening of the pulmonary trunk here. And this is the opening of the ascending aorta here. And if you look inside, you will find the leaflets of the semilunar valves in the pulmonary trunk and in the ascending arrow down. Now let's take a look at the other parts of the heart morphology. Seen from the front, this is the right atrium and this right oracle which is the functionalist appendage of the right atrium. The next structure that we see here, this is the left oracle. The left atrium is mostly behind. This is the outflow of the pulmonary trunk. This is known as the conus arteriosus or the pulmonary infundibular. And this is the outflow of the aorta which is referred to as the aortic vestibule. This is the right border of the heart which is formed by the right atrium. And there is a sulcus extending from the opening of the inferior vena cava to the opening of the superior vena cava and that sulcus is referred to as the sulcus terminalis. This is the left border of the heart which is formed mostly by the left ventricle and a little bit by the left oracle. This is the inferior border of the heart which is formed mostly by the right ventricle and a little bit by the left ventricle. And the superior border of the heart I told you when I put my finger inside the transverse pericardial sinus, it is formed mostly by the left atrium and a little bit by the right atrium. This is the apex of the heart which is in the fifth left intercostal space in the mid-clavicular line, one palm width from the mid-sternal line. This groove that we see here, this is the anterior intraventricular groove. And this groove that we see here going all the way around from the front is the anterior atrioventricular groove also referred to as the coronary sulcus. And this atrioventricular groove goes all the way behind and now I am turning the heart around and we can see that the atrioventricular groove runs all the way behind. This is the posterior part of the atrioventricular groove also referred to as the posterior coronary sulcus. So the portion above that is the atrium, the portion below that is the ventricle. This groove that you see here is the posterior interventricular groove and the junction between the posterior atrioventricular groove and the posterior interventricular groove is referred to as the crux of the heart. We can see now that we have turned the heart around 180 degrees and we are looking at the heart from behind and we can see that these are the openings of the pulmonary veins into the left atrium and this is a remnant of the left atrium which we have referred as the left oracle. This is a remnant of the valve of the inferior vena cava. So this is all for now for today's D-section. If you have any questions or comments please put them in the comment section below. Dr. Sanjay Sanyal signing out. Have a nice day. Hey guys, thank you for watching. Like this video and click the subscribe button.