 Good day, everybody. Dr. Sanjay Sanyal, Professor, Department Chair. This is going to be a demonstration of the venous drainage of the heart. So we have removed the heart from this cadaver and I'm holding it in front. Let's take a look at the anterior intraventricular groove. And we can see running in the anterior intraventricular groove is the LAD or the left anterior descending artery. And accompanying that, we have this vein here. This is the anterior intraventricular vein. So this is the beginning and we can see the full course of the anterior intraventricular vein here and we can see it going under. This anterior intraventricular vein, as it runs up in the intraventricular groove, it reaches left part of the anterior coronary sulcus and there it makes a bend to the left. This is the place where it becomes known as the great cardiac vein. And if you notice, when I pull here, it is moving here. So this is the continuation of the anterior intraventricular vein. This is the great cardiac vein. In the left part of the atrial intraventricular groove, it is accompanied by this artery that we can see here. This is the circumflex artery. So both of them run in the left part of the atrial intraventricular groove. And here we have an anatomical curiosity. Normally when an artery and a vein run together, the blood supply in the two of them are in opposite directions. That is what we know from our normal knowledge. But this is one of those rare cases where an artery and a vein, both of them are running together in the same groove and the blood flow in both of them are in the same direction. So this is a situation where we have the circumflex artery and the great cardiac vein, both of them running right to left. Blood flow is in this direction. Let's continue with the cardiac vein. The great cardiac vein now runs in the posterior coronary groove. And somewhere in the posterior aspect, it is not visible in this cadaver, a vein will come from the left atrium. And that is known as the oblique vein of the left atrium. Which some say is a remnant of the left superior vena keva. Once the oblique vein of the left atrium opens into the great cardiac vein, then the whole thing becomes known as the coronary sinus. And now we are tracing the coronary sinus. This is the coronary sinus. And the coronary sinus then continues in the coronary groove and it opens into the, and this is the opening, it opens into the right atrium. It was filled with clot and I removed that clot. And so we are seeing the opened out portion of the coronary sinus and we can see the remnant of the clot deep inside. It opens into the atrium near the interatrial septum, very close to the atrial ventricular node. So this is the full course of the coronary sinus, how it is formed and how it changes its name. Now, let's take a look at the tributaries of the great cardiac vein and the coronary sinus. So again, I'm turning the heart. We have already mentioned the formative vein, namely the anterior ventricular vein. So we shall not talk about that anymore. Let's take a look at this vein here, which I have lifted up and we can see it is opening into the great cardiac vein. This is the left marginal vein, which accompanies the left marginal artery, which is a branch of the circumflex artery. So that is one branch. Of course, there are many other branches, but they are unnamed branches. Now I'm turning the heart slowly. Now we have come to the diaphragmatic inferior surface. This is the posterior ventricular vein, which runs on the diaphragmatic or the inferior surface of the left ventricle. And we can see it is opening into the coronary sinus and we have separated it here to show the arteries. This is the coronary sinus. Now I'm going to turn it even further. We can see yet one more vein here and I've lifted it up here and we have cut it out from the coronary sinus. This is the middle cardiac vein. The middle cardiac vein runs in the posterior intraventricular groove, accompanied by the posterior descending artery, which is this one. And this opens into the coronary sinus. And finally, there is supposed to be a vein on this side here. That is known as a small cardiac vein, but in this particular cadaver, we do not see it. In all probability, it has been obliterated because of the previous myocardial infarction. So therefore, to summarize the four important tributaries of the venous system are marginal vein, the left marginal vein, posterior ventricular vein, middle cardiac vein, and the small cardiac vein, which usually opens at the coronary sinus near extermination, but we cannot see it here. So these are the various tributaries. At the opening in the gym, the coronary sinus may have a small valve and that is known as the valve of the coronary sinus also refers to as the thepsian valve. Which is not of much significance. There can be anterior cardiac veins, which open directly into the right atrium. And there can be smallest cardiac veins or venae cordus minimae or thepsian veins, which directly open into the chambers of the heart, but mostly to the right atrium. Those are very small and they cannot be seen here. So this is about the venous drainage of the heart. Thank you very much for watching. Dr. Sanjay Sanyal signing out. They will use the camera person. If you have any questions or comments, please put them in the comment section below. Have a nice day.