 This is going to be a demonstration of the morphology of the heart. So I'm holding the heart in my left hand. In a person, the heart is located the way I'm going to demonstrate. I have dorsiflexed my hand and radially deviated my hand. So this is the orientation of the heart of the person inside his or her chest wall. With this background, let's now mention the parts of the heart. This is the apex of the heart. This is formed mostly by the left ventricle. And this is located in the fifth left intercostal space, one palm width away from the sternum. And exactly diametrically opposite to the apex going in that direction is the base of the heart. So to show the base of the heart, I'm going to turn the heart now. So this is the location of the base of the heart. Inside to the base of the heart extends from the bifurcation of the pulmonary trunk indicated by my left index finger till this posterior coronary groove. This is the extent of the base of the heart. It is formed mostly by the left atrium and a little bit by the right atrium. What we see here is the left atrium. Now again, I'm going to turn the heart back. This is the right border of the heart. And this is formed by the right atrium. This is the inferior border of the heart. It is formed by the right ventricle. This is the left border of the heart, which is formed mostly by the left ventricle and a little bit by the left atrium. What about the superior border? To understand the superior border, let me first put my finger in this groove here. I'm going to put my finger in a place which is called the transverse sinus. It's actually a pericardial sinus. We have removed the pericardium. And if you notice, in front of my finger, we have the pulmonary trunk and we have the aortic outflow. And behind my finger, we have the superior vertebra. So this is the transverse sinus, which actually is a very important sinus used by cardiothoracic surgeons before they started open heart surgery. They put their finger in the transverse sinus to cannulate the pulmonary trunk and the aorta and connect it to the heart-log machine. To come back to where I was, when I put my finger in the transverse sinus, the lower limit of the transverse sinus where my finger is tracing right now, that is the superior border of the heart. And it is formed again by mostly by the left ventricle atrium and a little bit by the right atrium. What about the anterior or the sternocostal surface of the heart? This is the one which is in contact with the sternum and the chest wall. And this is formed mostly by the right ventricle. What about the inferior or the diaphragmatic surface of the heart? When I am putting my heart on my left palm, it was resting on the inferior or the diaphragmatic surface. This is formed mostly by the left ventricle. So these are the parts and the borders and the margins and the surfaces of the heart. Now to bring you to a few more specific things. We can see the pulmonary outflow here. And if you look inside, we can see the three semilunar valves here. Then we can see the aortic outflow here. Again, we can see the three semilunar valves. Now let me mention a quick word about the valves themselves. These are called semilunar valves because they are shaped like half a moon. The free margin of the valve is called the lunule. And the central portion of the lunule is thick and it is called the nodule. Thick and nodule is responsible for tight closure of the three valves. Then we can see this is the opening for the superior vena keva. And if I were to turn the heart, we can see the opening of the inferior vena keva. In this particular category, we had two openings, the inferior vena keva. One of them actually is the opening of the hepatic vein as it passed through the cable hiatus in the diaphragm. When I turn the heart, we can see this surface here. This, as I mentioned earlier, is the base of the heart. This is formed mostly by the left atrium. And we can see the openings of the pulmonary veins. Ideally, there should be two pulmonary veins on the right side and two pulmonary veins on the left side. But in this case, we are seeing that the left side, there is only one pulmonary vein opening and there are two pulmonary vein openings on the right side. They all open into the left atrium. This groove that we see here, this is referred to as the anterior interventricular groove. It is a groove between the right ventricle and the left ventricle. This groove that we see here on this side as well as on this side. This is referred to as the atrioventricular groove. Also referred to as the coronary groove. This is the anterior part of the atrioventricular groove, the right side and the left side. And if I turn, then we see the continuation of the atrioventricular groove here. So this is the full coronary groove. It is called coronary groove because it circles the heart like a crown. The portion above the coronary groove is the atria. The portion below the coronary groove are the ventricles. This is the posterior interventricular groove as opposed to the anterior interventricular groove, which I showed a little while earlier. Where the posterior interventricular groove meets the posterior coronary groove, this region of the heart is referred to as the crux of the heart. So these are some of the morphological aspects about the parts of the heart. Now let's come to the surface marking of the heart. I am going to position the thoracic cavity here just to show you what are the surface markings of the heart. And I have put the heart by the side of it. So this is the sternum. This is the manubrium. This is the second rib. This is the sternal angle of Louie. Third, fourth, fifth rib. Fifth intercostal space. This is on the left side. This is on the right side. So the surface marking of the heart will be left upper sternal border near the costal margin, number two. This is one point. Other point will be third rib on the right side near the sternal border. So we take one point here, number two, number three. Then we take sixth costochondral junction. And then we take the fifth intercostal space, one palm width away from the sternum, namely here. We join them. Second, third, sixth, fifth intercostal space. So this is the surface marking of the heart. This second to the third represents the superior border. From the third costochondral edge to the sixth costochondral edge represents the right border of the heart, which is formed by the right atrium. From the sixth costochondral edge to the fifth intercostal space marks the inferior border of the heart, which is marked by the right ventricle. This point refers to the apex of the heart, which is formed by the left ventricle. And from here, back to the second costochondral edge, refers to the left border of the heart, which is formed by the left ventricle. So this is the surface marking of the heart in the thoracic wall. Now let me mention a few clinical correlations. If you were to take a look at this appendage here, this is the oracle of the left atrium. And similarly, this is the oracle of the right atrium. These are non-functional appendages of the respective atria. However, in a condition known as atrial fibrillation, when the atrium is not contracting synchronously, but it is fibrillating like this the way my finger is showing, then blood can undergo stasis inside the oracles and can then lead to thrombus formation. And that thrombus is referred to as a ball thrombus. And this can be a source of embolus, which can go to the cerebral circulation. So that is all for now about the morphology and the other features about the heart. Stay tuned for the next video where I am going to demonstrate the coronary circulation and the next video after that where I am going to demonstrate the interior, the chambers of the heart. Thank you very much for watching. Dr. Sanjay Sanyal, Sanyod, Mr. Kendall Kumberbatch is the camera person. If you have any questions or comments, please put them in the comment section below. Have a nice day.