 In the next section series, the specimen that you see held in my left hand is the human heart. It has been harvested from one of the cannabals. Now, if you look closely, I'm holding the heart in the way it is normally oriented inside the thoracic cavity. So I'm holding the heart in my left hand. My left hand is dorsiflexed and radially deviated, so this is the anatomical position of the heart. So in this position, what you see, let me quickly give you an orientation of the margins of the surface and the borders of the heart. This is the apex of the heart, which is in the left intercostal space, one palm width from the mid-easternal line. This surface is the anterior of the sternocostal surface of the heart. This is the left border of the heart, this is the right border, this is the inferior border of the heart. And my hand is resting on the diaphragmatic or the inferior surface of the heart. And this is the superior border of the heart, which is formed by the right atrium in the left atrium, and I'll tell you more about it a little later. Let's identify quickly some of the structures that we are visible in this view. Straight away we can see these two great vessels here. This is the aorta, the sending aorta, this is the pulmonary tract, this is the left oracle, which is part of the left atrium, and this is the right oracle. Now what I'm going to do is I'm going to turn the heart around and I'm going to show you the other chambers. Most of the sternocostal surface that you see here is formed by the left ventricle, with the right ventricle. The inferior of the diaphragmatic surface of the heart is formed by the left ventricle, the left border is also formed by the left ventricle, the apex of the heart is formed by the left ventricle, the inferior border is formed mostly by the right ventricle, and the right border of the heart is formed by the right atrium. So these are the borders of the heart. Now I'm going to turn the heart. you see here, I have separated it. This is the left atrium. And as we all know, what is opening into the left atrium? We have the two left pulmonary veins. The two left pulmonary veins are opening and the two right pulmonary veins are opening. They have been dissected out and then formed a common opening here. So this is the left atrium. And this is the right atrium, which also has been opened up. But if we put them together, we can bring back the orientation. You can see this is the superior vena keva, which is opening into the right atrium. And this is the inferior vena keva, which is opening into the right atrium. And this is, as I told you earlier, is the oracle. So having mentioned these, now let me show you where is the transverse sinus. As we all know, during open heart surgery, we put our finger in the transverse sinus. And as you can see, my finger is right now in the transverse sinus. The transverse sinus is the space between arterial end and the venous end of the developing heart. And that persists in adult life. So in front of my index finger, you can see that this is the pulmonary trunk. And you can see the auricle. And behind my index finger, you can see this is the superior vena keva. So this is the transverse sinus. And the flow of the transverse sinus is formed by the superior border of the heart, where my finger has disappeared. And I can show it to you here. This is the flow of the transverse sinus. Okay, now that we have mentioned that, now let's come to the vessels of the heart. Those which we could dissect out and which I'm going to demonstrate to you. So let's start from the aorta. So I have separated the pulmonary trunk from the aorta as much as I could. And after separating them, let's see what we can find. Here, we notice that this is the right coronary, excuse me, right coronary osteum. Because artery is very friable, when I was dissecting it, it tore off. So this is the opening on the right coronary artery. And this is the right coronary osteum, which comes out from the right coronary sinus. So this is the right coronary artery. Again, to show you, this is the osteum. And this is the opening on the arterial side. So this is the right coronary artery. So let's put it back in its place. Once we put it back in its place, you can see that it is overlapped by the right oracle. So it runs in the anterior coronary groove or the right anterior atrium ventricular groove under the right oracle. So therefore, transiently disappears. So let's reflect back the oracle and we can see it is running in the right anterior atrium ventricular groove. As it continues, it gives us to the right marginal branch. So we can see the right marginal branch here. And we can see another branch here. We can see that they're giving out two brands. And then the right coronary artery continues. It continues on the posterior atrium ventricular groove. And you can see it is continuing. And it continues. Again, it is because of its probability it got ruptured here. And in the region of the crux of the heart, the crux of the heart is the junction between the posterior atrium ventricular groove and the coronary groove. In the region of the crux of the heart, it turns downwards and it runs down as the posterior atrium ventricular artery. So this is the course in a nutshell of the right coronary artery. You can see the branch is coming right from its origin. Before concluding about this, it will not be out of place to mention that the right coronary artery also gives a branch to the right to the to the SA node, sanitary node, which is near the origin of the opening of the supravena caver. And near the crux of the heart, the same right coronary artery also gives a branch to the AB node in the majority of the population. So the right coronary artery is a major supplier of the right ventricle and it also supplies the posterior one-third of the thickness of the interventricular septum. So that is the supply of the right coronary artery. Now let's take again come back to the anatomical position. This is the pulmonary trunk. Let me remove this. This is the left oracle. Now let me reflect this and here we see is the origin of the left coronary artery. This is the left main coronary artery or as we call it LMCA. Mercifully this did not rupture. This is still coming out. So this is the left coronary sinus and you can see the left coronary artery emerging. Again just like the right side, transiently it disappears under the left oracle. And then it reappears again. So let me just reflect back the left oracle. And once we do that, we can see that this is the left main coronary artery. And immediately afterwards, as we all know, it divides into the anterior interventricular artery, which is also a very big artery. The surgeons call it LAD, left anterior descending artery. And you can see it is descending in the anterior interventricular groove. And when it's descending down, it gives rise to multiple branches on the left ventricle. Here we can see one of them. We can see another small one here. There will be several here. They are referred to as diagonal arteries. So we can have diagonal 1, diagonal 2, diagonal 3. They are called D1, D2, D3, etc. Then the next, after it is given off to the anterior interventricular or the LAD, the rest of the left coronary artery continues. As you can see here, my probe is under that. And that is the circumflex artery. The circumflex artery then continues running. It runs in the posterior atrioventricular groove on the left side. And as it runs, it gives rise to the left marginal artery, which you can see here. It is the left marginal artery. And then the rest of the circumflex artery then continues running in the posterior atrioventricular groove. And in this place, it is accompanied by the great cardiac vein, which is going to subsequently become the coronary sinus. So you can see that it is accompanied by the great cardiac vein, which is going to become the coronary sinus. And they are running in the posterior interventricular groove. And it runs in the posterior interventricular groove till it almost reaches the right coronary artery, but it does not directly enhance the most of it. And we can see part of it here. We can see part of its course here. So this is the course of the circumflex artery. Part of the coronary sinus has been dissected out here. And I can show you the opening of the coronary sinus on the right atrium. This, as I told you earlier, is the opening of the right atrium. Again, to bring you up to speed, this is the superior vena keva. And this is the inferior vena keva. We have opened up the right atrium along the sulcus terminalis. And we can see that this is the sinus venerium part of the right atrium. And my finger, this is the atrioventricular valve. And that, where my probe has disappeared, is the opening of the coronary sinus. My probe has disappeared into the opening of the coronary sinus. So this, in a nutshell, ladies and gentlemen, is the first series of dissection of the heart, whereby I have demonstrated the borders, margin surfaces of the heart, the cross structures, the atria. And more importantly, I have demonstrated the right coronary artery from its origin to its termination, the left coronary artery with its branches from its origin to its termination. And I've shown you the coronary sinus. Thank you very much for watching. Thank you, Selvi. Thank you, Doug, for being nice camera persons. Have a nice day. If there are any questions or comments, put them in the comment section below.