 This is Dr. Sanjay Sanyal, the next episode of the dissection series, and the camera person is Mr. Doug McLaren. So what you see in front of you here are two long specimens. The one on my left hand, this is the right lung of the patient, and this on my right hand is the left lung of the patient. Both of them have been retrieved from this cadaver here. The dead teach the living. So let me quickly describe some of the landmarks as we can see them on the outer surface of the lung as well as some of the landmarks that we can see them on the inner surface or the mediasional surface of the lung. So let's start with the right lung. So the first thing are the parts of the lung that we see here. What you see here is the apex of the lung. This is the anterior border of the lung, as you can see it's quite sharp, and this is the one which fits into the costo-mediasional recess. This sharp border that you see here, curvilinear, this is the inferior border, this is the one which fits into the costo-diaphragmatic recess. This concave surface is the one which fits into the right, onto the right dome of the diaphragm. This is the mediasional surface for the mediasurface of the lung, and this is the costo-surface of the lung which is the sternocostal surface of the lung which is in relation to the ribs and the sternum. As you can see the sternocostal surface goes all the way from the front to the back, and this is the posterior border of the lung. Having said that, now let me tell you a few important things that we can see in the right lung here. Straight forward, straight away we notice this fissure here. This is the fissure which is called the horizontal fissure, and this is the one which starts at the level of the fourth costal cartilage and runs along the fourth rib and meets with the next fissure here which is the oblique fissure. I will tell you the continuation of this horizontal fissure on the medial surface when I come to the medial surface. Now let's take the next fissure, the oblique fissure. This one starts, it cuts the inferior border of the lung at the level of the sixth costal cartilage, goes obliquely up and posteriorly, and it comes to the medial surface, again I will show it to you when I come to the medial surface. By dividing the right lung by means of these two fissures we have three lobes of the right lung, the superior lobe, the middle lobe, and the inferior lobe. If you notice the superior lobe and the middle lobe are related more to the front of the chest wall and the inferior lobe is related more to the back of the chest wall. This is of clinical importance. The next thing that we notice are certain shallow depressions on the surface of the lung, and I'm sure you would have already guessed it, these are the costal markings or the rib markings caused by the impressions of the ribs. So these are the salient features that we can see on the external surface of the lung, there's nothing more to explain. The lung normally is supposed to be pale pinkish in color and what you see is the visceral pleura covering the lung with a few blood vessels on top. Okay, having said that, now let's come to the medial, the medial-stenial surface or the medial surface of the lung because this has got several important landmarks. Anyway, let's continue with where we left off with oblique and the middle fissure. The middle fissure continues onto the medial surface and it meets this region of the lung on the medial surface which is known as the high lobe. It meets the high lobe from the anterior aspect. Here it is not so obvious but if we open the visceral pleura we should be able to see it here. Likewise, the oblique fissure, it meets the high lobe from two different places. It continues and meets the high lobe from the infrolateral aspect and, sorry, it meets the high lobe from the anterior inferior aspect and the same oblique fissure continues and cuts through the posterior margin of the lung and meets the high lobe from the posterior superior aspect. So this is the termination of the oblique fissure. So therefore again we can see that the inferior lobe of the lung is related most to the posterior chest wall and the anterior middle lobes are related to the anterior chest wall. Okay. Now let's come to the next important landmark that you can see here is this structure in front of you. This is the high lobe of the lung. What exactly do we mean by the high lobe of the lung? The high lobe refers to the place where the bronchovascular structures which enter or leave the lung from the medial standard. So here we have the, and this is also the place where the medistinal part of parietal pleura becomes continuous with the visceral pleura. So therefore the continuity of the parietal and the visceral pleura occurs here. And incidentally a sleeve of pleura extends down from the high lobe where also the medistinal pleura becomes continuous with the visceral pleura and that sleeve of pleura which only the cut section can be seen here that is known as the pulmonary ligament. That's just of anatomical significance. What do we see in the high lobe before I go to the other landmarks? We see the cut sections of the bronchi here. You can feel it by its cartilaginous feet. So this is the right principal bronchus which divides into three lobe bronchi superior, middle and inferior. So this is the principal bronchus. We can see the cut sections of the veins, pulmonary vein and we can see the cut sections of the pulmonary artery. So vein, artery, bronchi. These are the structures which are enclosed. Additionally we can see a few black dots here. Those are actually the lymph nodes. Why are they black? Because they have absorbed all the carbon particles from the atmosphere, from the polluted atmosphere and therefore they have become black. So these are the bronchopulmonary lymph nodes or the hyalur lymph nodes and you can see at least three of them. One here, one here, one here. So this is the hyalur. Now let's look at some of the important other landmarks. First you can see this big concavity here on the medial surface, on the medial surface. This is the cardiac impression. This is where the right pulmonary surface of the heart is in relation with and which part of the heart is in relation with here is the right atrium. So this area is related to the right atrium. Then we see a groove here. This is the right brachiosephalic vein which becomes continuous with the superior vena keva. And here we can see another shallow groove here which is the inferior vena keva. So the right brachiosephalic superior vena keva enters into the right atrium because the right atrium is here and the inferior vena keva also enters into the right atrium. Then we can see this depression. This is where you have the subclavian atrium. The internal carotid, the brachiosephalic artery divides into the right subclavian and the right common carotid artery. So that is the impression produced by that. Just behind the bronchus, we see a group, a depression here. This is the depression which is produced by the hooking of the azygous vein. The azygous vein, it climbs up on the posterior medial stenum, it hooks above the bronchus and it opens into the superior vena keva which I mentioned comes down like this. Okay, continuing, there is an area here which is related to the trachea and to the isophagus. And the isophagus area continues down in this region here. So this is the isophageal area. So this isophageal area continues down like this. And as I have already mentioned, this is the blunt posterior margin of the lung. So this in a nutshell are the important landmarks that we see on the medial stenum surface of the lung. On the external surface, on the medial surface of the right lung, thank you very much for watching. Ladies and gentlemen, if you have any questions or comments, please put them in the comment section below. Have a nice day. Dr. Sanjay Sanyal signing off. Thank you, Doug.