 Hello everyone, in this session we will be learning about the lungs and the heart ok. In this session, I will be also showing the 3D models of lungs and the heart. So, stay tuned till the end of this particular session. So, lungs I will be covering in these headings. I will cover the external features of the lung, then side determination of the lung, and various relations of the lung, and structures at the high limb of the lung. And lastly, we will cover about the bronchopulmonary segments and its applied anatomy. And in heart, I will cover the exterior of the heart, interior of the heart, the coronary circulation as well as the applied anatomy of the heart ok. So, in all we will be covering the lungs and the heart. So, let us begin with the external features of the lung. For that, let us directly go to the 3D model which we have. So, here we can see the specimen of the right lung. So, what are the external features in the right lung? Here we can see the upper part, this is the apex of the lung. The lower broad part is referred to as the base of the lung. And it has borders and surfaces. This anterior border, this is the sharp anterior border. And this part is the broad posterior border. And there are 2 surfaces. This surface is the costal surface. And this surface is the medial surface ok. Medial surface further subdivided into a medial senile surface and a vertebral surface ok. And with this basic idea, we should be able to determine the side of the lung. How to determine that this lung is of right side and not of the left side? So, for determining the side of the lung, we will have to justify in 3 dimensions. Just like we determine side for the bones by saying 3 dimensions. Similarly, for organs also we will have to say. So, for superior and inferior, the point which we can say is the apex of the lung is on the superior aspect. For medial and lateral, we can say the hilum of the lung is on the medial aspect ok. This region of the lung that is the hilum of the lung, this should be on the medial aspect. And anterior and posterior, this is the most important critical point for side determination of the lung. The anterior part is the, this border as we can see, this is the sharp anterior border ok. And the border which is on the posterior aspect, this is the broad posterior border ok. And never say that this lung has 3 lobes, that is why this is of the right side ok. Because there may be variations in the lobes of the lung. So, that is why that point should be avoided ok. Always justify side by justifying 3 dimensions. So, this is the lung of the right side, anterior border, posterior border as well as there is an inferior border here. Inferior border separates the coastal surface as well as the medial surface from the base of the lung ok. This region is the base of the lung. So, this oval border this is the inferior border of the lung ok. So, 3 borders and 3 surfaces we can remember anterior, posterior and inferior border. Surfaces are coastal surface, medial surface and the base also referred to as the diaphragmatic surface ok. Because this region is related with the diaphragm and this region here this is related with the ribs as well as the intercostal muscles right. And for the medial surface we will see the relations in a different image. Before that first let us look at the left lung as well. So, here we can see the specimen of the left lung. So, again try to justify the side of this left lung. So, we can say that it has got a sharp anterior border here. The apex is pointed towards the upper aspect and this is the high lung facing on the medial aspect ok. That is why this is the lung of the left side ok. And it also has similar borders and surfaces as that of the right lung. To understand the various relations of the medial surface let us look at different image. So, here we can see this is the right sided medial stenum which is seen the right lung has been removed. Imagine as if the right lung is removed the right lung was here right. So, imagine as if it is removed this is the anterior border of the lung. So, this will be in this region ok. Imagine you have just removed the right lung and we are giving the medial surface of the right lung ok. And similar cadaveric image is shown on the right side. So, what all structures we can see in this region. So, automatically that will form the relations of the medial surface of the right lung ok. And we should be able to like approximately show the locations of those structures in the specimen of the lung ok. So, what all structures we can extrapolate from this image. This we can see this is the heart right. So, which part of the heart is this this region is the right atrium of the heart ok. So, the right atrium of the heart is related in this region ok. And as we know in the right atrium there is opening of the superior vena cava as well as the inferior vena cava. So, SVC, IVC. So, small parts of IVC and SVC are related here. And there is a vein draining into the superior vena cava that is the azygus vein ok. So, azygus vein is related along the medial surface. And apart from that we can see trachea and esophagus ok. So, these two tubes are also related in this region trachea and esophagus. So, anterior aspect there will be trachea posterior aspect esophagus ok. And we can see certain nerves which are related here this is the phrenic nerve here. So, on the anterior aspect there is phrenic nerve and on the posterior aspect near the esophagus there is vagus nerve ok. So, two nerves which we can remember is the phrenic nerve and vagus nerve ok. So, phrenic nerve on the anterior aspect vagus nerve on the posterior aspect. So, all these structures we should be able to show approximately in the dissected specimen of the lung. So, in this region there will be right atrium then in the upper part superior vena cava inferior vena cava ok trachea esophagus phrenic nerve vagus nerve. So, at least these structures we should be able to locate on the specimen of the lung ok. Similarly, let us look at the left lung. So, now imagine as if we are moving the left sided medial stenum. So, the left lung was in this region we have removed the left lung this anterior border of the lung. So, it will be located here. So, imagine you have we have just deflected the left lung from this region. So, whatever structures are seen here will be related on the medial stenal surface of the left lung ok. So, which part of the heart will be this we are moving the medial stenum from the left side this is the left ventricle right. So, left ventricle we can see the impression of the left ventricle here and from the left ventricle we know the ascending aorta rises right which continues as the arch of aorta and continues as the descending thoracic aorta ok. So, so this ascending aorta arch and the descending aorta. So, all these are related here we can see here ascending arch and then the descending aorta ok. And trachea and esophagus they both are also related here and also the nerves which we saw in the right lung, phrenic now vagus now those will also be related here and apart from that left recurrent laryngeal nerve is also related ok. So, for the heart we should remember that left ventricle is related with the left lung right atrium is related with the right lung ok. So, similar things we should be able to show in the dissected specimen of the lung we can see the left sided medial stenal surface we can see a clear cut depression here U shaped inverted U shaped depression this is the arch of aorta and the descending thoracic aorta ok impression for arch and the descending thoracic aorta and esophagus trachea left ventricle is the region of the left ventricle ok. And when we see the anterior border of the left lung it will show a projection in the lower aspect that projection is referred to as the lingula of the left lung ok. It is characteristic only for the left lung because of the presence of the heart there is an extension from the left side of the lung that is the lingula of the lung ok. So, this was all about the structures in the medial stenal relations of the lung. Now, let us understand these two terms root of the lung and hilum of the lung. So, what is the difference between these two terms root is the structures which enter or leave the lung ok and hilum is the site on the lung in which these structures enter or exit ok. I will just clarify it with these descriptions root includes the structures and hilum is the site of entry and exit ok. So, in this image various structures are shown here. So, this is the these structures are the root of the lung ok and in this image only the site on the lung is seen where these structures are entering or exiting. So, this is the hilum of the lung ok. So, this difference one should know and we should also know that which structures are related in the hilum of the right lung and left lung. So, let us see the arrangement of structures of the root of the lung which enters into the hilum. So, for the right sided hilum anterior to posterior in general we can remember as vein artery and bronchus ok in both sides. This is the right sided hilum we are seeing and this is the left sided hilum again we can remember as vein artery and bronchus VAB we can remember from anterior to posterior. So, here is the superior pulmonary vein in the artery and on the posterior aspect there is bronchus. In the right lung there is epaterial as well as high arterial bronchus. In the left lung there is only one single left principal bronchus ok and when we trace the lower aspect of the hilum there is a vein inferior pulmonary vein ok. Inferior pulmonary vein it is just adjacent to a structure called as pulmonary ligament. It is the site where the parietal pleura and the visceral pleura meet and it extends downwards that is the pulmonary ligament ok. It provides a blind space for this inferior pulmonary vein to expand during increased venous return ok. So, to determine the structures in the hilum of the lung from the anterior most aspect the first structure that we encounter is the superior pulmonary vein and the structure which we see on the inferior most aspect is also a vein inferior pulmonary vein ok and the posterior most structure is the bronchus that is how we can easily identify. Let us try to identify in one of the hilum. Let us try to identify the structures in this hilum of the left lung. So, here we can see the anterior most structure which we can see this is the left superior pulmonary vein and the inferior most structure here this is also the left inferior pulmonary vein ok. So, two veins we can see here then the middle part here this is the artery this is the left pulmonary artery and the posterior most structure here we can see this is the left main bronchus ok and then if it is a right lung. So, it will have a bronchus above the pulmonary artery as well ok. So, that is why it is called as epartirial bronchus and high partirial bronchus ok. So, that is how we should be able to identify the various structures in the hilum of the lung and in books bronchial arteries may be written in the hilum. So, but you would not be able to spot it out because bronchial arteries are the arteries with supply the wall of the bronchus ok. So, those will be very thin. So, that cannot be identified as a big structure ok. So, by mistake do not try to identify a big structure as a bronchial artery ok this point you should remember. Now, let us cover the bronchopulmonary segments in the lung it is the most important topic in the lung it is most frequently asked as a short note. So, everyone should be clear with this topic. So, here we can see multiple bronchopulmonary segments let us try to understand it. So, water bronchopulmonary segment it is all characteristic features are important it is a subdivision of the lobe of the lung. It is pyramidal in shape with its apex directed towards the hilum and base is towards the surface of the lung ok. It is a wedge shaped structure like this apex towards the hilum, base towards the outer surface of the lung ok. It is surrounded by a connective tissue it is aerated by a segmental or a tertiary bronchus this is very important. As we know there is a trachea which divides into the right main bronchus and the left main bronchus right. The right bronchus divides into a lobar bronchus in the right lung there are 3 lobes right. So, there will be 3 lobar bronchus and each lobar bronchus when it further divides. So, that division is referred to as segmental bronchus for each of the bronchopulmonary segments. So, it is aerated by a segmental or a tertiary bronchus never write terminal bronchus in place of the tertiary bronchus because these are 2 different things. So, this the word tertiary is very important tertiary or you can simply say that it is a segmental bronchus ok. Each segment has its own artery it is a branch of the pulmonary artery and it has an own lymphatic drainage ok, but veins are intersegmental ok. Veins carry oxygenated blood in lungs. So, that is why it is shown in red color. So, veins are actually intersegmental ok. The blue colored which is shown here it is actually the branch of the pulmonary artery ok. So, in bronchopulmonary segment veins are intersegmental. So, these are well defined anatomical functional and surgical units of the lung. So, it can be surgically resected ok. Now, let us try to label the bronchopulmonary segments of each lung. So, each lung has got 10 bronchopulmonary segments ok. So, this is segment 1 apical then posterior anterior segment 2, 3 then medial lateral then 6 is apical basal then 8, 9, 10. Number 7 is not seen here that is on the medial aspect ok. So, to show the number 7 you will have to draw the medial surface of the lung and show a segment just in front of the hyalum. So, this is the bronchopulmonary segments of the right lung and this is the bronchopulmonary segments of the left lung. In this instead of medial and lateral there is superior lingular and inferior lingular ok that is one difference as compared to that of the right lung ok. So, it looks very difficult to remember the names. So, let us try to simplify how to remember these bronchopulmonary segments. You can easily remember by remember by this mnemonic apam and amap ok where a refers to the apical. So, these numbers also correspond to the names of the lobes ok. So, this is the apical then posterior anterior then 4 is lateral 5 is medial then apical basal medial basal anterior basal this is the apical. This is the apical basal medial basal is on the medial aspect this is anterior basal lateral basal and posterior basal ok. And for the left lung just replace 4 and 5 by superior lingular and inferior lingular ok. So, lateral and medial if you can just replace it by superior lingular and inferior lingular other segments are same for the left lung ok. This is that is how easily we can remember and just try to draw the diagram according to the lobes ok. In the right lung there are 3 lobes right. So, this is one oblique fissure then there is a horizontal fissure 4 and 5 are in the medial lobe. In the left this region 4 and 5 is replaced by superior lingular and inferior lingular ok. And in the blood anatomy of the broncopulmonary segments aspiration pneumonia in supine position it is more common due to prolonged bed read in patients and segment 6 is the most vulnerable the apical basal segment. So, abscess formation occurs most more frequently here and because of the broncopulmonary segment certain diseases can get localized to one particular segment for example bronchiactasis it gets localized to one segment and if a disease is localized then segmental resection of the lung can be done ok. For example if disease is only in segment 3 so only this part of the lung can be resected out because it is a surgical unit of the lung. So, that is the applied anatomy of broncopulmonary segments ok. Now let us start with the heart. So, here we can see the specimen of the heart. Let us have a brief overview with the images and then I will show you the 3D models of the heart as well. So, here we can see the exterior of the heart viewed from the anterior aspect and this image shows the exterior of the heart viewed from the posterior aspect. Details about the borders and surfaces will cover in the 3D model and in this image we can see the interior of the heart. So, interior of various chambers are shown here. This is the interior of the right atrium. This image shows the interior of the right ventricle. This image shows the interior of the left ventricle and this image shows the interior of the left atrium ok. So, all four chambers interior will be covering and while studying the interior few basic rules we have to remember. So, these are the rules which we need to remember while describing the interior of the heart. Each chamber shows rough part and smooth part ok. The right atrium shows rough anterior part and smooth posterior part. Both ventricles show rough inflowing part and smooth outflowing part and left atrium it is entirely smooth except the region of the left oracle ok. So, whenever we are describing a particular chamber we should remember that it will have some rough part and some smooth part ok. That is how we can begin the description of that particular chamber. So, this is the basic rule we can remember. So, with this basic idea let us look at the 3D models of the heart. So, here we can see the actual dissected specimen of the heart. So, while describing the heart in general we can say that it has four chambers the two atrium and the two ventricles and between the atrium and the ventricle there is atrio-ventricular groove. In between the ventricles there is interventricular groove on the anterior aspect as well as the posterior aspect and there is also an interatrial groove ok. And let us learn about the borders and surfaces of the heart. So, the surface which is seen on the anterior aspect this is the sternocostal surface in relation with the sternum as well as the coastal cartilages right. So, this is the sternocostal surface in the part of the heart which is seen flat here which is resting on the diaphragm. This surface is the diaphragmatic surface of the heart and the surface which is on the left side that is referred to as the left surface of the heart ok. And the apex in the base if we see this pointed part this is the apex of the heart directed towards the left and diagonally opposite the apex this region formed by both the atrium this is the base of the heart ok. Base of the heart is formed mainly by the left atrium ok. It is formed by both the atrium, but majority is formed by the left atrium ok. So, apex, base and surfaces we have covered. Now, let us cover the borders of the heart extending from the superior vena keva to the inferior vena keva. There is the right border of the heart it separates the sternocostal surface from the base of the heart ok. And extending from the inferior vena keva up to the apex of the heart this border here this is the inferior border of the heart. It separates the sternocostal surface from the diaphragmatic surface and extending from the apex of the heart to the left oracle there is left border of the heart. So the left border of the heart separates sternocostal surface from the left surface and there is also an upper border of the heart which is actually obscured by this great vessels pulmonary trunk and aorta. So these three borders at least we can remember the right border separating sternocostal surface from the base of the heart inferior border separating sternocostal surface from the diaphragmatic surface and left border separating sternocostal surface from the left surface. So each border is separating sternocostal surface from one other surface. In general you can remember this. So this was about the external features of the heart and also we can see the coronary arteries here. This is the right coronary artery. This is a branch from the left coronary artery, the anterior interventricular artery and the artery which is seen here that is the left coronary artery that is a branch of left coronary called as the left circumplex artery, details of branches we will see and on the posterior aspect near the posterior interventricular groove that is posterior interventricular artery. Let's see the interior of the heart as well. In this specimen we can see the structures of the interior of the heart. So here we can see this chamber of the heart is the right atrium. This chamber is the right ventricle. This cut part here this is the left ventricle and this chamber here this is the left atrium. Okay. Let's see this region. This is the interior of the right atrium. So what all structures are seen in the interior of the right atrium? It shows rough anterior part and smooth posterior part. So if we just reflect this, we can see some roughness here. So if we just reflect it in its anatomical position, this is actually the rough anterior part. Okay. Rough anterior part is formed by this crista terminalis and musculi pectinate. Okay. Transposed muscle ridges which we can see this is the musculi pectinate and this is the crista terminalis. And behind which there is smooth posterior part. Smooth posterior part shows an oval depression that is called as the fossa ovalis and there is a margin covering it that is referred to as the limbus fossa ovalis. Okay. And there is an opening of a vein inside the right atrium that is the opening of coronary sinus and the two major veins also open here the superior vena keva and the interior vena keva. Okay. And the largest opening seen here is the right atrio ventricular orifice. So all these are the openings in the interior of the right atrium and the location of the conducting system of the heart the SA node is located near the upper part of the crista terminalis near the superior vena keva. And AV node is located in a region which is called as triangle of cox. It is formed by the septal cusp of the tricuspid wall then opening of the coronary sinus and there is an elevated sub-endocardial ridge here. So these three structures from the boundaries of the triangle of cox and the AV node is located there. Okay. So this was about the interior of the right atrium. Let's see the interior of the right ventricle. Right ventricle shows rough inflowing part and smooth outflowing part. Okay. This is the rough inflowing part and both this part are separated by an elevated crest which is called as supra ventricular crest. Okay. And the rough inflowing part is described as trabeculae carnae. Trabeculae carnae includes ridges, bridges and papillary muscles. Okay. Bridges are fixed elevations on the surface of the ventricle. Bridges are fixed at two ends and three in between and pillars are the papillary muscles. Okay. This tall structures which we can see this is the papillary muscles. Okay. Papillary muscles at the apex here there is cordate end in a which go towards the cusps. And here we can see this one example of a bridge. This is referred to as the septomarginal trabeculae which carries the right branch of the AV bundle. Okay. And supra ventricular crest that we discussed that is the example of a ridge and smooth outflowing part this region is referred to as the infundibulum of the right ventricle. Okay. In left ventricle also similar things are there. One difference that we can see is of the papillary muscle. In right ventricle there are three papillary muscles anterior posterior and septal. In left ventricle there is only two papillary muscles. Okay. In left ventricle also there is rough inflowing part, smooth outflowing part. Rough inflowing part is also called as trabeculae carnae. Okay. Similar to that of the right ventricle. And the outflowing part here I told you it is infundibulum of the right ventricle. On the left ventricle it is called as vestibule of the left ventricle. Okay. And let us see the interior of the left atrium. You can see it is entirely smooth except in this region we can see some roughness. So that roughness is caused by this ridge, this part that is the left oracle. Okay. So this is the left atrium. So this was all about the interior of the chambers of the heart. Now let us continue with the coronary arteries. This image also we can see the coronary arteries. This is the right coronary artery arising from the aorta here. And this is the left coronary artery. It is soon dividing into anterior intraventricular artery and left circumflex artery. Okay. This is the left circumflex artery. Here we can see the major branches of the right coronary artery and left coronary artery. On the right coronary artery there is right marginal artery. Here we can see this blood vessel. This one. Right marginal artery. Then posterior intraventricular artery on the posterior aspect and S.A. nodal artery. Okay. These are the main branches of the right coronary artery. The left coronary artery we can see this branch. This is the left anterior descending artery also called as anterior intraventricular artery. Then a branch which goes behind along the intraventricular groove on the left side that is circumflex artery. And diagonal artery it is corresponding to the marginal artery of the right side. Okay. Here we can see right marginal artery. Similar artery seen on the left side it is labeled as diagonal artery. Okay. So these are the vessels which supply the heart. Origin of these vessels are important. Right coronary artery arises from the anterior aortic sinus. Left coronary artery arises from the left posterior aortic sinus. Okay. Right posterior aortic sinus is also referred to as non-coronary sinus. It produces a bulge in the interior of the right atrium. That bulge is referred to as torus aorticus. Okay. In this image we can see both the atrium are removed and we can see the walls of the heart. This is the pulmonary wall, aortic wall, tricuspid wall and bicuspid wall, the mitral wall. Okay. And also we can see the origin of the coronary arteries. This is the right coronary artery, anterior aortic sinus is here and left posterior aortic sinus is here. This is the left coronary artery. We can see it dividing into left anterior descending and this is the left circumflex artery. Okay. And this is the non-coronary sinus. Let us see the venous drainage of the heart. So venous drainage the largest vein which drains the heart is this coronary sinus. Okay. SVC and IVC are also veins, large veins here but they do not drain the heart, they drain the body. Okay. So when we speak about veins draining the heart, the largest vein draining the heart is this coronary sinus and there are many other vessels which open into the coronary sinus and coronary sinus ultimately opens into the right atrium. Okay. And anterior cardiac veins they directly open into the right atrium. Okay. They do not go into the coronary sinus. Okay. So which other veins are opening into the coronary sinus? Here we can see the right marginal vein, then left marginal vein, then middle cardiac vein is on the posterior aspect dotted thing which we can see this is on the posterior aspect and on the anterior aspect here this is great cardiac vein. Okay. So great cardiac vein on the anterior aspect, middle cardiac vein on the posterior aspect. There is also small cardiac vein here. Small cardiac vein, then marginal veins are there, right left, then there is an oblique vein called as oblique vein of marshal. Also there is one more vein which is not shown in this image, there is posterior vein of the left ventricle. Okay. So almost all veins they open into the coronary sinus and coronary sinus ultimately opens into the right atrium. Right. And only this anterior cardiac veins they directly open into the right atrium. Okay. Now let us cover the applied anatomy of the heart. So angina pectoris and myocardial infarction, we should know the difference between these two. Angina pectoris means there is an atherometous plague in the interior of the vessel and there is ischemia because of this. Okay. And whereas myocardial infarction means the vessel is completely blocked. So the heart attack which is commonly referred, also referred to as myocardial infarction which the vessel is completely blocked. Okay. And in angina pectoris, the vessel is partially obstructed. So this is one difference we should know between angina and myocardial infarction. So angina pectoris, it then occurs on exertion. Okay. Whenever there is increased exertion or the person walks for too far. So, so that causes difficulty and myocardial infarction may occur suddenly. Okay. So suddenly something may come and block the blood vessel and it may lead to myocardial infarction. Then so if this occurs myocardial infarction, so there are corrective measures which are include which are called as coronary bypass surgery or angioplasty. bypass surgery means for example, there is a block here, a vessel is bypassed from the main trunk. Okay. The main trunk is ascending out from there itself, a vessel may be bypassed to the part of the heart distilled to the block. Okay. That is referred to as bypass and angioplasty means for example, there is a block here. So a stent will be passed here, this block will be removed and the stent will be placed here permanently like this. Okay. And the blood will be able to flow through the stent that is referred to as angioplasty. Okay. So we should know the difference between bypass surgery and angioplasty. Okay. Then valvular stenosis, so there are multiple valves right, tricuspid, bicuspid then the semilunar valves. So those valves may get stenosed like mitral stenosis or tricuspid stenosis and their respective symptoms may be according to that. Okay. So let us summarize what we have covered in this particular session. We covered the external features of the lung, then how to determine the side of the lung by three dimensions. Then I covered various relations of the lung, then hyalum of the lung, the various structures forming that difference between the hyalum and the root of the lung, then we covered the bronchopulmonary segments with it supplied anatomy. And in heart we learnt about the exterior, interior, the artery supplying it, the veins draining the heart and lastly the applied anatomy. Okay. So for PDF handout of this particular session you all can WhatsApp me at this number and please do watch other sessions of this YouTube channel. Okay. Thank you. Thank you.