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Hello. Are you ready to start? Um, hi Patrick. Um just um if you can present, try presenting your s your slides. Yeah. Is that ok? Can I can you hear it and see it? Yes. Yes, we can, but it's not present. Uh Yeah. And so this is not a full screen. Yeah. No, it's good. Are you ready? Are you happy? Yeah, so welcome everyone. Um um ok. I think people are joining gradually. So which is good and encouraging. Um I'm and um welcome to this teaching series on basics of cardiothoracic surgery. This is going to be 1/6 session uh in the last month and half or so. We've had several sessions um on different topics from cardiopulmonary bypass to aortic surgery, to cardiac physiology, cardiac ectomy. And this is going to be a 66 session which is on the anatomy of the thorax and lungs. And this session is going to be taken by Patrick Holly, who is a clinical fellow at Port A in the UK. And thank you Patrick for agreeing to teach this session and um thank everyone for registering and participating in this session. Um So it's going to run for just, um, the teaching itself is going to be about, uh, 15 minutes for five minutes after which there's going to be a question. Um, just at the end, let last 5 to 10 minutes for anyone to ask questions. Um, um, I think Patrick will be happy enough to answer any questions that anyone has. Um, and, um, just to also announce that the next session for this teaching series, which is going to be on um coronary artery bypass graft surgery. This was supposed to have been taken two weeks ago actually. But um the, the teacher had to postpone it, which was supposed to be the last session on the cardiac aspect of this teaching series. And so it's sort of coming in between after the thoracic session I started, but that's fine. The session, coronary artery bypass graft surgery session is going to um next week, Saturday, same time 7 p.m. The event is already on me. Do you can register for it at the end of this series? I'm going to just post the um the link to register for the session also so that you'll be able to register for it. But I look forward to seeing you guys there and now I'm just going to leave it to Patrick um as it takes us through the anatomy of the thorax and lungs. Thanks for thank you NAMI and thank you for inviting me to present this uh teaching session. And thank you for everybody uh for joining on a Saturday evening. I don't know what time it is from where you're joining at. But so, yes, the, the title of my presentation is the anatomy of the thorax and uh and, and lungs and this is going to be the sixth session of the basics of uh cardiothoracic surgery. So, um what, what I plan or the, the outline of uh this teaching session is going to be from outside in basically. So the idea is that, you know, we will start with the cage that surrounds, you know, the thoracic cavity and then we will move from there. So towards the lungs uh in a sort of like an orderly fashion and uh this will encompass with, you know, the, the mechanism of respiration, including the diaphragms, the ribs and the accessory muscles. And then following that, we will talk about the, the pleura, um you know, covering the lung and the chest wall. And then finally, we will get into the uh the most, uh you know, the lungs and the, the bronchus, the most kind of like uh proximal structures. And then we can also talk about uh thoracic surgery, you know, given that this is uh you know, a, a teaching series on, on cardiothoracic surgery, you know, lungs and, you know, anything involving the lungs and the pleura is more the area of thoracic surgery rather than cardiac. So we can have a little talk about the indications and the sort of the anatomy of the incisions in cardiac uh in thoracic surgery, which I think will be interesting, you know, following up discussion about the anatomy. So, um the thoracic cage, so the thoracic cage is, um, you know, it surrounds the thoracic cavity. It's a uh a semirigid bony structure. Um So it does expand, you know, with inspiration. So it isn't fully rigid. Um but it, it is, it has a protective property to it, uh you know, protective to the lungs and it has cartilaginous joints, uh you know, between the uh the, the sternum and the, and the ribs also. So, uh the um it consists of 12 ribs, um the manubrium, um unfortunately, I can't point here, but the manubrium corresponds to about the first rib and then going down in the midline below the manubrium. You have the actual body of the sternum and the xiphoid process at the very tip, it's done. It's the uh the, the bit that's actually hanging out on the bottom of the sternum. Um And then this is the uh the anterior aspect on the, on the um posterior aspect, the, the ribs sort of go around and then they attach to uh the uh vertebral column. And uh this uh the thoracic cavity ranges posteriorly from um the thoracic vertebra one to the thoracic vertebra 12. Um So, looking more deeply or more in detail to the um the sternum So the sternum, uh you know, like we were just talking about is composed of three bones actually. And it's the manubrium that's most proximal, that's most cranial rather. And then um the Zippo process is most cold or, and in between you have the body. So, um they're joined together by a cartilaginous joint. Um So they do move. It's not, you know, it's not one full bone. However, you know, as people get more and more elderly, the the there is an, you know, a process of oss of this joint. So, you know, in somebody who's 70 or 80 or 90 years of age, maybe, you know, the bone will be much more ossified, you know, much more bone like structure than uh somebody who is, you know, like 2030 years of age, much younger. So an important landmark um that uh is, is, is important in regional anatomy is the uh the angle of le. So this is a, this is, you know, an important landmark in anatomy that's actually very heavily examined as well. I mean, in every examination in the world, this angle of Louis is quite important. And the reason why it's actually quite, it gives you a great idea of where you are. So, you know, everybody can, you know, while they're sitting in front of the computer, even you can probably feel your angle of Louis. It's a very prominent um prominent sort of protrusion of the, the sternum and it, the reason why it's so important is because, you know, almost immediately, you know, where the second rib is. So, you know, in, in a patient who's, you know, lying on an operating theater, you can very easily feel the second or the angle of lo and then you can then move your hand left or right. And then you will know immediately that this is the second rib. And also uh it is um you know, an important landmark because it corresponds to um the vertebral level T four slash T five. So it's, you know, lower T four, higher T five. And um and there are lots of things that are happening uh at this vertebral level. So the um this is called the transthoracic um uh plane. And um the, the arch of the aorta is at this level, the trachea is bifurcating is at this level. So that's to say the carina is at this level and the union of the Azygos vein um and the, this uh superior vena cava is at this level also. So, you know, it's important from that point of view as well. You know, you, there are a lot of things that are actually happening at this level. And um the body has provided us, the anatomy of the body has provided us with quite an easily, um you know, identifiable um regional anatomical landmark. And at the bottom of this uh this whole um sternum, you have the xiphoid process, which uh you know, it kind of, you know, when you look at the, the picture on the right hand side, it, you know, it, it almost looks like as if it's a tooth or something like that. But why this is so why the zip process is important? This is actually the diaphragm will attach to the zip process. And um and when you're trying to kind of predict where the diaphragm is, the xiphoid process is, you know, a useful landmark to because you know that it will attach to the xiphoid process. And therefore, you can actually understand where the, the diaphragm is going to go. And subsequently, when you're making your incision in thoracic surgery, if you have, you know, correctly predicted it, you will not end up below the diaphragm in the liver, for example, which is a, you know, one of the complications of uh thoracic surgery moving on to the, the ribs. Um So there are 12 ribs in total. Um, like we mentioned on the first slide and um, the first seven of these are true ribs. So they are, you know, the posterior, they come out of the uh the thoracic vertebra and they attach onto the, um, the sternum or the body of the sternum or the manubrium or the uh the xiphoid. Um However, the there are also 89 and 10 false ribs which do not attach to anything they attach to sort of a cartilaginous process that has a, a common attachment into the body of the sternum. And then finally, you have the 11th and 12th rib which are floating ribs and they don't attach to anything and their length, they can, they can be very, very short or they can be very, very long. So it varies from, from body to body, the length of these 11th and 12th ribs. So the ribs they do actually have, you know, so they have a protective property, but also they have um you know, a, a property in, you know, inspiration, respiration in general because as you inspire the, the sort of the, the, you know, the physics of the ribs is that, you know, it moves, it moves in a way that actually expands the thoracic cavity. And it also the way that it's, you know, it's built is that, you know, it will actually sort of um in or like move the sternum. So, but these movements are actually called, you know, bucket handle movement where, you know, the bucket is as the bucket handle is moving towards the actual bucket, it's enlarging. And then you have the pump handle movement where, you know, as you, as you put the pump down and up, your sternum is moving up and down. And as a result, the thoracic cavity is expanding in size and we will see in a couple of slides time that this is actually one of the most important things in breathing, you know, your thoracic cavity needs to be able to expand for you to be able to inspire going to the uh the back of the rib. So um the, the back of the rib is you can see the thoracic uh vertebra. So from T one to T 12 and they correspond to the, um you know, the ribs as you can see. But also quite importantly, there is the scapula. So I appreciate that this is not part of the thoracic uh you know, cavity or the thoracic cage, but the, the scapula provides us with important landmarks as well. Now, you know, I will not go into the details of, you know, like, oh yeah, supraspinatus muscle and infraspinous muscle and all these things. But you know what's important in terms of regional anatomy, you know, landmarks, especially specific for cardiothoracic surgery is that the spine of the scapula, um you know, will correspond to the, the third uh clavicle or the third rib rather sorry. So, um you know, this is once again an important landmark when you're, you know, at the operating theater and the patient is lying on his back. So sometimes, you know, in, in a trauma situation or in a situation where, you know, it's, it's not, you know, practical to, you know, put the patient on the front of the body, then, you know, the scapula provides us a good idea of what level rib. Um we are looking at from uh you know, once again the landmarks on the scapula. So there are two main landmarks, the, the spine of the scapula, which corresponds to three. And probably more importantly, and once again, quite easily found is the tip of the scapula, which corresponds to the seventh rib. Now you can, when you're, when you're, when you're actually, when you have like, you know, a specimen in front of you or you're doing a physical examination, you can move the scapula up and down, which and if you put your hand on the back of the body, then you will feel quite easily the tip of the scapula. And then you will quickly understand that, you know, this corresponds to the seventh rib and then you can actually make your mind out about, you know, where you want to put your incision according to that. So once again, this is an important landmark for thoracic surgeons because this will help determine where you're going to make your incision. If you're going to do a posterolateral thoracotomy, which you know, goes all the way, almost past the, the anterior axillary line, all the way up to the sometimes all the way up to the thoracic vertebra, you know, maybe not as that far, but you know, the, the, the tip of the um the scapula will definitely be a huge aid in, you know, finding the uh the correct location where you're going to make your thoracotomy, you know, at the end of this presentation, we will talk about the uh the, the incisions as well. So keep that in mind, you know, like in a live specimen, the tip of the scapula is quite important from that point of view. Now, I want to kind of like make uh you know, now that we've talked about the sternum, I I pre this is not about anatomy exactly, but this is, this is uh you know, um this is pathology really. But you can, it has like uh you know, an anatomical um representation that's quite striking. So this uh the um the sternum is formed from uh sternal bars and uh they come from mesenchymal condensations. Now, this is a, you know, on the right, I, you know, I should have actually put down here, but this is an embryological illustration and the mesenchymal condensations come together to form the sternal bars. And then as a result, they form the sternum once they fuse together. Now, a failure to fuse will result in, you know, a condition called pectus excavatum. And um and as you can see in the picture on the uh left lower side of the slide, you know, the, the uh the, the sternum will have this sort of depression where the uh the sternal bars have not come together. And this uh it can actually be rectified by inserting what's called a NAS bar that you will, you, you can um you can sort of uh connect the uh depressed areas to a bar and this will elevate the uh the sternum uh to its normal position. So this is a bit of a kind of like a, a tangent. But, you know, it's, it brings into account the, uh the, the sternal anatomy. Now moving on to why all of this is really important because, you know, the whole point of, you know, you know, the lungs and um, the thorax is, you know, ok, the heart is there, but also you need to be able to breathe. And you know, the b breathing aspect is, you know, the thoracic cage plays a huge role and there are certain muscles that are, you know, paramount to the uh the function of the lungs. So, um, you know, there are two types of breathing. Um, you know, quiet breathing. This is when, you know, you're listening to this session right now and you're sitting in front of your computer and this is a time when you're doing quiet breathing where you're not really recruiting, um, you know, muscles from any other parts of the body. You're just using your primary um principal muscles of breathing, which are mainly the diaphragm, but also the intercostal muscles. Now, let's, uh you know, in the scenario where you are going through some strenuous exercise, you've decided to go for a run. For example, then what happens is is that you start to recruit um muscles from the surrounding anatomy to increase your thoracic cavity. So the, when you're, when you're doing active breathing, you, um you know, so your diaphragm and your intercostals are, are working. And in addition to that, you start recruiting your abdominal muscles. And the idea behind this is that, you know, when the abdominal muscles uh contract, then the uh intraabdominal pressure will be uh raised and then this will actually move the diaphragm up and down a little bit more. So this is in sort of like uh you know, an extra measure that the body can take in strenuous exercise. And actually, this can also, it doesn't necessarily have to be strenuous exercise. You can also take the account the example where uh you know, uh a person is pregnant and the, the, as a result, fetus will increase the intraabdominal pressure. And as a result, this will have an impact on the diaphragm as you know, the um this will, you know, increase the, the, the, the length of the uh the diaphragm and then the diaphragm will bring it back down. So you actually have uh it will be kind of like active breathing uh because your intraabdominal um pressure is increased. And then, um then when you're actually in, you know, a more emergency, a medical emergency situation or you're struggling to breathe, you have shortness of breath, um then you start to recruit accessory muscles such as, you know, the sternocleidal muscle or the scaly muscles. But you know, these are the two ones that they're commonly discussed as, you know, accessory muscles because you can see it when somebody is in respiratory distress. But in fact, you, so you will recruit, you know, your pectoralis major will be moving, your Serato anterior will be moving your latissimus dorsi will be moving. So, you know, you, you're actually recruiting a significant amount of numb uh muscles uh depending on how severe the respiratory distress is as well. And, but, you know, you like the most important concept or the point here is that all of these muscles uh are trying to increase the uh the volume of the thoracic cavity. So, when the sternocleidomastoid is contracting, it's pushing up the, the clavicle in an attempt to actually improve or increase the uh the the volume of the thoracic cavity. So, you know, these muscles, the, the there is no exhaustive list of it. But, you know, if you, if you generally understand why they are contracting, then you'll have a better understanding of, you know, which muscles might be contracting because they are, you know, any muscle that will increase the uh the volume of the thoracic cavity is essentially an accessory muscle of respiration. So, moving on to the most important muscle of respiration. Um So this is the diaphragm and um I've, you know, the, so the diaphragm, um it is the, the lowest point of the thoracic cavity. So the, the lungs sit on the diaphragm and um and when it contracts it, then, you know, it pushes down and then when it, you know, releases, when you expire, it then comes back up. And this is, you can see it as a representation of on an x-ray. Um I mean, you see that, you know, on inspiration, the diaphragm is much more um you know, at, at a lower position than uh on expiration where it's come up, it's relaxed a little bit. Now, you know, on this x-ray, there's actually another finding that we haven't spoken about, but there is actually a pneumothorax on this right x-ray. But this is, this is not why I actually put it there. But it, I think it's a good illustration that, you know, you can see the uh the diaphragm moving up and down if there was such a thing as a live chest x-ray or, you know, in the, in the, in the radiology department, if you see it, you know, you will actually see it moving up and down maybe five or six centimeters. Um and the, the diaphragm itself. So, um it's, you know, the bottom of the thoracic cavity, most important muscle of respiration, it's supplied by the phrenic nerve and the phrenic nerve, the um it arises from the cervical plexus or the cervical vertebral column and from 345. So the, you can also say 345 keeps the diaphragm alive. But, you know, um so this. And the reason why the uh the, the supply of the phrenic nerve is, you know, in such a, you know, a far away position compared to the diaphragm is also has an embryological explanation where the, the diaphragm moves down. As you know, the uh just go, when you're going through the embryological phases, it's pierced by the uh inferior vena cava, the esophagus and the aorta. So the inferior vena cava will pierce the uh diaphragm at T eight, the esophagus will pierce it at T 10 and the aorta will pierce it at uh T 12. So all of these hiatuses um that give rise to these structures have uh you know, uh peripheral um or, you know, accessory structures going through it as well. For example, the vagus nerve will go with the esophagus through T 10. But these are the main three hiatuses on the uh on the diaphragm. So that's the general idea of the diaphragm. And uh just to emphasize, I, I think the most important thing on this uh diaphragm is that, you know, it is by far the most important muscle of respiration and, you know, at, at any given time when you're, you're just doing quiet, you know, respiration, the diaphragm will in fact be, you know, the only muscle that's working on us. So, moving on to know. So we're now, you know, beyond the thoracic cage and, you know, we're moving towards the uh the uh you know, the, the content of the thoracic cavity. Um And um so the thoracic cavity, let's talk about that. First of all. So the, the, the central component of the thoracic cavity is what's called the mediastinum. And the metasone, this is, you know, it's, it's sort of a pouch or it's a, you know, it's a, it's a bunch of structures actually. And um these are namely the, the heart and, you know, the, the major uh great vessels of the heart, the esophagus, the trachea, the phrenic nerve, the thoracic duct, the thymus and the lymph node. Um and then, you know, you have then on both sides, you have your right and your left lung. So this is, you know, those are, those are main, mainly the structures of the um the thoracic cavity. And in order to actually get into the thoracic cavity, you have to go through what's represented by this picture on the right, um the thoracic inlet and the thoracic inlet corresponds to um posteriorly, it is thoracic vertebra number one laterally, it is the first vertebra and then anteriorly, it is the manubrium. Now, there can also be something called thoracic inlet syndrome. Um And this happens when there is an extra cervical vertebra um or C seven the seventh uh cervical vertebra is, is actually encroaching or is, you know, obstructing or making it even smaller um the thoracic inlet. So you can see on the right imagine the first vertebra but imagine the, the C seven, the uh actually coming in a little bit even uh you know, sort of encroaching the uh the, the, the, the thoracic in that making it smaller. And then as a result, um all the structures inside will begin to squeeze. So um major vessels, what structures are going to get squeezed. So, these are the uh the contents of the thoracic uh inlet and these are the major vessels. So you're talking about, you know, um the common cars, the subclavian is there, you know, trachea, uh esophagus, phrenic nerve vagus, um and apex of both lungs. So both of the lungs um will actually just come out a little bit from the thoracic uh from the, from the thoracic inlet. So you will see the, the tip of the lung. It is not 100% inside the thoracic cavity. There is a bit called the coup Pola that actually exceeds the uh the limits of the thoracic cavity and it kind of comes out of the thoracic uh inlet. So this is the, the meds. Now, I appreciate this, you know, this uh image on the right can be a little bit, you know, difficult to understand that first look. But it, it's, it's a diagram of um you know, the uh the what the structures in the, the meds before we get to the lungs. So, the mediastinum itself, um like we said, it's a bundle of structures, you see like how many structures are in the meds and it's divided into four sections. So the first section uh or the first two divisions is superior and inferior. And this is divided at the angle of Louis. So this is where we were talking about the, you know, the sternum man manubrium joint. So the the second uh rib or t four t five. So once again, you know, this emphasizes the importance of this anatomical landmark. So the uh the superior mediastinum and then the inferior mediastinum and then the inferior mediastinum is then subdivided into three. So, anterior middle and posterior and the anterior mediastinum contains the thymus, the phrenic nerve, the middle mediastinum contains the heart and then the posterior mediastinum will contain all, you know, all sorts of things like the vagus nerve, the esophagus, the descending or the um and so on. And then this is in uh this is why you know, this, this diagram is trying to achieve it. It's trying to achieve, it's kind of showing, you know, um a breakdown uh of um where all the uh structures are coming from and where they can be found in the thoracic cavity. Now, of uh of um thoracic surgical, um you know, interest one of the operations that can be done in thoracic surgery, surgery through a sternotomy. So when you open up the sternum and you have access to the anterior Medin is a thymectomy. So you see the thymus is sitting very uh much anterior in the mediastinum. And if there is a thymoma and uh this thymoma is now becoming symptomatic, um primarily through myasthenia gravis, the thymoma will then be removed from the anterior mediastinum. But there a lot of occasions where it's just an anterior mediastinal mass. So you it, it will be a differential diagnosis between thy thymoma teratoma or uh terrible lymphoma. Um So this is one of the operations that, you know, this anatomy actually comes into play where, you know, you have to remove something from the anterior mediastinum. And therefore, you will have to know the structures in the anterior mediastinum and what is lying behind it directly, which is the phrenic nerve. So if imagine you are doing an operation on this thymus and the phrenic nerve, which is coming from 345 cervical vertebra down to the diaphragm. The most important muscle of respiration is directly behind the structure that you are trying to remove. So this is when anatomy actually plays a quite an important role in, you know, um in surgery, basically. So if you're not aware that the phrenic nerve is behind the thymus, and if you're resecting a thymoma from the anterior me, then you will, you run the risk of uh of um of uh damaging it. And then as a result, you will have a, a um a paralysis of the hemidiaphragm and the diaphragm will come up, it will be completely relaxed basically. And then in the, in the posterior mediastinum. Well, the middle MSM is reserved basically for the heart, the posterior mediastinum, you have, you know, your esophagus descending over at that and then uh your left recurrent laryngeal nerve, the right recurrent laryngeal nerve will actually um will uh will, you know, make a U turn around the subclavian, the right subclavian and go back up. And this is AAA nerve that is uh you know, um important in the context of thyroid surgery because uh you know, the thyroid is close by to all these nerves, but the thyroid is not in the thorax. So we are not really interested in it right now, the mediastinum. Um so just to actually give you a better idea of, you know, like the gross anatomy of the mediastinum, this is kind of what it looks like. Um This is an image from, you know, gray's anatomy. Uh And you see what's important here is, and, and another thing that's actually quite heavily examined is the course of the uh the, the phrenic and the, the vague vague nerve. You see that the uh the, the, the phrenic nerve runs it, it enters through the thoracic inlet and then it runs in front of the hilum. So it is the most anterior, most uh uh structure in the thoracic cavity. Um and the Vegas then will do the opposite, will run deep or, and it will run deep and then it will run posterior to the hilum. And this is, you know, correct for both sides. Actually, I'm going to return to the previous slide because it's also you can see that, you know, the phrenic is running in front of the heart and then the vagus is running uh behind the heart. And then you can also say the same thing for the hilum of the lungs. So the phrenic will be running in front of the hilum of the lung and the vagus will be running behind posterior, the hi of the lung. So once again, when you're dissecting around the hilum of the lung, both of these structures are, you know, very much, you know, in the vicinity in the neighborhood. So both of these structures are very important to take care and you know, preserve because it will have direct implications on the, the patient if they are damaged, moving on. Now, we are actually approaching the lung more and more. Um So this is um the uh the structure that uh is sort of an envelope of the lung. Um It is a uh a, a thin ses membrane and um it is called the, the, the pleura. So the, the pleura will um you know, attach both to the uh the the visceral surface and the the chest wall, uh the visceral surface of the lung and the chest wall. And very importantly, there is a potential space. So, you know, the lung and the chest wall, sit on top of each other and the pleura allows it to actually move quite freely on each other. So there, there is no kind of like friction between the two. So it's a sort of a, what they call it, a glistening surface. So it's where it, you know, it's very smooth and it kind of like, you know, just, it's like silk, you know, they move, it moves very easily on each other. And in between these two cavities, you, these two membranes, you have what's called the pleural cavity and the pleural cavity is quite an important space. Um You know, the, so the there's a, there's a, a physical vector that the lung in itself is trying to collapse and then the chest wall in itself is trying to expand and there is a very fine, um there's a very fine balance between the two of these. So when you actually maximally inspire, you are at the point where the lung, the vector of the lung is getting stronger and stronger because the chest wall is expanding further and further and the lung wants to, you know, collapse. So you get to the point where the maximum expansion happens and then, you know, the physics, the laws of physics will bring it back down and you know, and then the, the chest wall will then, you know, get to its maximum and then it will want to expand again. So these two structures are actually the vectors of these two structures are in the opposite direction. And as a result, the pleural cavity has an overall negative intra uh intra pleural intra cavity, um intrapleural pleural uh pressure. And why this is so important is if the integrity of the pleural cavity for any reason is lost, then all of a sudden this coupling of the chest wall and the lungs are also lost. So if for example, you have, you know, air coming into the pleural cavity as a result of a stabbing, let's say, or you know, any kind of interstitial lung disease, let's say, or COPD or you know, whatever bulla, um then the coupling between these two will be lost and then the lung will collapse and the chest wall will expand. So there is no longer this kind of fine balance where they are moving together. It's just, you know, it's decoupled. This will be a pneumothorax. If in the example of a stabbing, for example, you are inspiring and air is coming in. But you also have air, you know, air is coming in, but it is not able to go out of the pleural cavity. Then what will happen is that the air will continue to build in the the pleural cavity and then it will start to actually put pressure on the heart um because you know, it is not able to escape. So from a tension pneumothorax, the patient will not die, you know, primarily from the tension pneumothorax, the patient will die because there is air that is captured in the pleural cavity that is now pressing on the heart. So this is important, this is a life threatening situation. And then finally, you will have pleural effusion. If for example, um there is a patient who has uh you know, a cancer of the pleura mesothelioma. They are going to produce a lot of fluid as a result of the inflammation. And this is going to result in a pleural effusion. If you get stabbed, there is a possibility that you damage one of your arteries, you get a hemothorax. So there's blood in the uh in the pleural cavity. And also empyema is when there's pus in the um pleural cavity. Another word for empyema is uh pyothorax. So, you know, you see the trend here pneumo is air thorax, hemo is blood thorax. Pio is pus thorax basically. And all of these will result in a decoupling between the lung and the chest wall, which is the main idea basically. And then finally, we are at the lungs. So, uh this is what the lungs look like from uh you know, from where we started off from the beginning when the thoracic cage is around it. And like I said before, you see this ulla, the apex of the lung, the dome of the pleura um is uh just, you know, protruding out of the uh thoracic inlet and um and then you can see the lung uh through the uh the, the ribs. Now, the um the base of the lung is the diaphragm. We talked about this in the diaphragm slide, the costal surfaces, you know, laterally speaking, the lung is, you know, touching the, all of the ribs. And then the, the bit that we, the, the section or the part that we cannot see here is the uh the, the hilar structure. So the hilum of the lung, which you know, is, is, you know, touching or, you know, very close contact with the mediastinum that we discussed this bundle of structures in the center. And you can actually see on this picture, there's an outline of the heart. Um that is uh that gives you an idea of where the hilum is now also important for uh physical examination purposes. Um The uh the, the borders of the lungs are not um you know, universal. So there is no one border of the lung inferiorly speaking, I am. So in the midclavicular line, it's at the sixth rib in the mid axiliary line, it's at the eighth rib and you know, on the back posteriorly it goes all the way down to the 10th rib. So um there are 22 things that could be important here. So if you do, if you listen with your um stethoscope at, you know, midclavicular line at the, the rib, let's say, I know it will not, it's not, you know, a particular place that you usually listen to, but you will not hear the lung or, you know, if you know the, if you listen or another example will be, you know, in renal surgery, when they're doing like a renal transplant, the, the, the kidneys are usually found around the 11th, uh, rib, 11th or 12th. So posteriorly, you see that the lung ends at the 10th rib. You know, one of the common complications is actually a pneumothorax in renal surgery because all of a sudden, you know, while they're operating on the uh the uh the kidney, instead of the 11th rib, they go through the 10th rib and now they are in the lung. So this will result in a pneumothorax and one more common complication that is related to the anatomy is when they're putting in a subclavian uh line, subclavian, uh line, central line. Um the, the subclavian artery will run directly on, on the first rib. And as you can see in this image, the uh the cupula or the pleura or the apex of the lung, it is directly behind the first rib. So in the example, where you, instead of putting the uh the catheter in the uh subclavian artery, if you put it in the apex of the lung, the result will be a pneumothorax. And this all of these complications actually arise from the anatomy of, you know, the structures of the lung or the phrenic nerve or whatever, you know. So, moving on to the actual lung and the the the higher structures, the right lung is uh composed of three lobes. So the upper lobe, the middle lobe and the lower lobe and um and it has two main fissures, the oblique fissure that uh that separates the lower lobe from the middle and upper lobe and then the upper fis uh or the, the upper and the middle lobe are then separated by the uh uh horizontal fissure. Now, and each lobe, it's important to emphasize, has its own bronchus and its own blood vessel supply. And uh one important thing about the right side is that, you know, the right main bronchus is quite, very much shorter and wider and more vertical. Um And um this is where, you know, in, in the example where, you know, let's say a baby has swallowed. Um you know, some toy, it will very likely end up in the right lung because of the bronchus being much shorter, wider and more vertical compared to the left main bronchus. The left lung, the left lung is two lobes and also divided by the oblique fissure, very much, very impressive uh cardiac impression on the left lung. And it is smaller in size because the heart takes up uh space in the left side of the thoracic cavity. And then uh you know, um the ascending aorta also has an impression on the left lung. Uh because it is in direct contact. And um I, I forgot to touch on the actual hilar structures. So you have the pulmonary artery. This is um coming from the um the right ventricle and then the pulmonary vein going into the left atrium and then you have the bronchus as well. And then also um coming direct, it's not represented here but coming directly um of the um the aorta are the bronchial arteries which supply the actual parenchyma of the, the lung. So, the pulmonary artery and vein are, you know, important structures for oxygenation, de oxygenation, but they do not supply the actual parenchyma of the lung. The parenchyma of the lung is supplied by the bronchial arteries that come off the aorta and the, the size of the lung. These bronchial arteries are quite small actually. And the, the, the, the size of the lung is big because it's actually filled with air. So, you know, the parenchyma when you take the air out is much smaller than what you actually see in um an aerated lung. And moving on this is, you know, getting even more. So we came out from the thoracic C cage and now we're going in and in and in and we're going even further in and in the lungs, you have what are called segments. Um So in each lobe, you have multiple segments and the segments correspond to the bronchial tree. So the, let's say, you know, let's just take this example where the trachea is going to the right. So you have the right main bronchus and then the right main bronchus will give a right upper bronchus. And then this will then be, you know, segmental, you will have the posterior, anterior and apical subsegments of the right upper bronchus, upper lobe bronchus. And then the um the the surgical implication of this is that instead of taking an entire lobe, you could take, you know, just a segment, especially if the, if you find a nodule or you know what you're trying to remove is in a certain segment, then why are you taking the entire lobe? You can just take this segment. But the difficulty is that, you know, it's difficult to actually see in real life. Um what segments and where are the borders of these segments. So, um the, you know, the, the resection of a lobe is a little bit more uh you know, favored or more popular, but more and more with, you know, technology with uh imaging and things like that. They are moving towards this, you know, sub lobar segmentectomy. And this is where the anatomy once again comes into play. And because you can see, you know how colorful on the right hand side, this the, the the the lungs are, they all represent segments. And if you remove a lung nodule from any given segment, this is almost, you know, this is as good as a lobar resection. So, um moving on, I know it's 45 past. So, you know, we were going to do Q and A but very quickly, I will talk a little bit about thoracic surgery. So, the main indications in thoracic surgery are the main idea is lung cancer. So, that's probably the, the bread and butter, you know, the most important operation. Um You'll do, you know if thoracic surgery is something that you are interested in doing or considering doing, you're looking at doing a lot of pneumothorax surgery, you know, pleurectomy, uh pleurodesis, which is a bedside procedure. Oh, no, sorry, I'm sorry, blood pleurodesis was a bedside procedure to pleurodesis, uh intraoperatively and P MA washout. So you're going to be dealing with, you know, patients that are, have severe uh lung, chest infections that are now become, are stuck basically to the uh chest wall because they are ongoing long term infections. And the way to do it is just to take it out to wash it out. Uh you know, chronic obstructive pulmonary disease is another thing that you will be dealing with. So this will be lung volume reduction where you remove parts of the lung that are not being oxygenated and end the bronchial valve where you can uh you put, you know, um a valve into the bronchus. So it is not oxygenated and therefore there is no blood going in that direction. Chest wall reconstruction. Now, we've talked about PX Carum for example, this is, you know, a good example of chest wall reconstruction. I I know for example, that uh that you can do a thoracoplasty for people with severe tuberculosis where you take out some of the ribs and then you depress the, the chest wall so that the tuberculosis does not reappear. These are very sort of, these are quite, you know, advanced surgery. But you know, the as an idea, this is what you do. So you, you remove the actual space where the TB can uh reappear trauma. So road traffic accident patient comes in with flail chest, you know, a certain segment of the uh part of the the entire chest wall is broken. Then you are the person who has uh you know, responsible to put that back together and also the uh esophagus surgery. So cancer of the esophagus, for example, now this isn't everywhere in the United Kingdom, for example, it's the upper G I upper gastrointestinal surgeons who do this. And but in other countries, like for example, in Korea, you know, the thoracic surgeons will be doing the uh esophageal surgery as well. Quick look at the incisions. Um you know, now that we've got a good idea of um the anatomy. So um this is a Posterolateral thoracotomy. This is one of the most traditional ways to um to get to the thoracic cavity, you make um an incision uh below the tip of the uh the scapula. So it's important to know where the tip of the scapula is. Uh you can actually see that, you know, it's an s shaped incision and this s shape is, you know, giving to the, uh the tip of the scapula. It's going to be difficult to get into the thoracic cavity if you're going to hit the tip of the scapula. So you need to go below that. Um And then you, uh, you know, usually you will uh you know, preserve the serratus, you will go through the latissimus dorsi and then you will arrive at the ribs and then you can then go through the ribs into the thoracic cavity and then you do whatever you need to do if it's a lobectomy or whatever it is. Next one sternotomy. We've talked about the sternum, we've talked about the manubrium, the body, the xiphoid sternotomy. You know, this is a midline incision and it will give you access to any kind of cardiac operation, you know, coronary artery, bypass grafting or any kind of anterior mediastinal uh resection. Uh sternotomy is the uh the the choice clamshell. So clamshell is, I mean, uh to be quite honest with you, I've never seen this in my entire life. But uh you know, this is a, this is uh especially for lung lung transplantation. It's a uh an important uh incision and also uh in patients who have uh trauma. And it's difficult to understand where the trauma is coming from. So is it on the right side, left side, you are not entirely sure. Or if it's completely obliterate, obliterated, then a clamps shell will give you the maximum amount of exposure to the uh organs of the uh thoracic cavity. And then finally a hemi clamshell. So this is also a good one for, you know, uh uh unilateral uh transplantation. It, it's, you can see the uh the um the kind of the, the exposure that you get from a hemi clamps shell. You, you see all the uh the, the, the uh uh the great vessels, the heart, another good um another good incision to get access to get, you know, quite this compared to a thoracotomy, this will give you a much larger exposure. But it is also, you know, it's much rarer because the, the thoracotomy gives you quite good exposure as it is. And then finally, a quick word about, you know, video assisted thoracoscopic. You know, nowadays, um you know, on any operating list, you might see a vats, lobectomy or a vats um segmentectomy or, and this is, you know, um compared to the incisions that we saw on the previous slides, much smaller incision and um you know, less pain, less hospital stay. Uh so essentially minimally invasive. And uh and then you see, uh you know, you can do there are multiple ways of doing it. So uni part or two ports, three ports, and then you put the camera through and then you use your stapler or you use your uh instruments to uh to um, you know, manipulate the lung. And then finally on the, on the left hand side for anybody who hasn't experienced it. This is what it looks like. So you, you're the surgeon, you are sitting in front of the uh the patient with your uh instruments and you're looking at the screen rather than looking inside the body. And uh and that concludes my session, my uh talk about the anatomy of the uh thorax and the lungs. Uh I provided, you know, my contact details for anybody who wants to get in touch with any questions or anything like that. And uh I thank you very much for joining me on this Saturday evening. So um I'm back to you if any. Thank you very much Patrick. Um That was very detailed and those are just in time. Really? Thank you very much. Um I think we will move to the question and answer sessions. I can see that there are some questions on the chart already. Um mm Very technical questions. I dont understand enough of it. But the first one from addi says, can you use a nerve sparing cyber operative technique for robotic video, a thymectomy? OK. Metallic patients with myasthenia gravis. Um You have an answer to that. I don't. Yeah. So I mean, I like in, in for this um you know, an mesal mass resection. You know, it is actually very well suited for robotic aided uh thoracic surgery. Um And the, the question here is, you know, you can perform a nerve sparing zip um thymectomy uh in patients with myasthenia gravis. Um Yes. So, I mean, I'm not entirely sure about the uh the, the staging of the thyro, how far you can resect, but you can, I think eight centimeters, you will be able to do it. Well, let me, let me put it this way. So you can definitely do a a thymectomy um through in a sub um approach um in a robot assisted thoracoscopic way. And I I am pretty sure that you can do an eight centimeter one, but I am not entirely sure about that. Yeah. Um I hope that answers part of your questions. And the um the second question is in patients with multiple rib fractures on cardiopulmonary resuscitation, other surgical stabilization of rib fractures compared with non-operating treatment. Um not in the traumatic implication of a longer intensive care admission postoperatively after chest wall injury is a specific. Um so, so the um the the approach in this circumstance is so the um so the description of the rib fractures is very important here. So if the the rib fractures are undisplaced and you know, they are not causing any respiratory distress, then a conservative um approach or conservative management is probably the best thing to do. However, if you have a segment um that, you know, corresponds to a, a couple of ribs, at least like three ribs, let's say four ribs and they are displaced and they are actually facing on your CT scan, they are facing into the lung. Then you have a different circumstance where you, you know, you're better off doing a rib fixation because this might lead to a new muscle ache and it is going to cause a lot of pain uh for the patient. So the thing to do in a, in a displaced um flail chest would then be to take the patient to the theater and do a fixation. Of course, given the patient or giving or you know, considering that the patient is hemodynamic, stable and all these kind of things. Yeah, Patri. Um Then the second, the other question is how common is recurrent pectus keum after ravage surgery? Um I don't know what, what, which surgery is. Do you have any idea what that is? I, no, not, not, I don't recognize the name at all ra surgery. Um Let me we can continue reading. So in the cross, I think you can. Yeah, and the cause by technique are safe and effective as the para que and could this cause by for complex pe deformities for remodeling of the entire chest wall? Mm So, I mean the crossbar technique, I mean from, I think this is referring to, you know, um a NSS surgery. So noss operation and this is, you know, the NOSS bar. I mean, I don't know if this is incorrect, then maybe type in the chat. But, you know, so what happens with this is that, you know, you realize that the patient has Pectus Carba at quite a young age and then, um, the Nuss bars, they all have different sizes. So, you know, it might, and then they correspond to the actual throughout the, uh the cavity. So it's not like a one size fits all situation. And then this noss bar then will be changed, you know, um when the patient is growing up and then by the time they get to 17, 18 years of age, then, you know, the nassar is then removed. Um And I mean, I don't have, you know, a lot of experience with PP excavatum, but from, you know, the, the, the small sample size of uh patients that I've seen, you do actually get quite a, a good result. So, I mean, it isn't like, you know, uh, an anatomically speaking, it isn't a pristine sternum, but it is definitely much better than, uh you know, the um the, the sort of depressed sternum, it's sort of like, you know, the, the result is better, but it's not like as if you don't have the, the condition at all. So, I mean, the bar does have an effect. Perfect. And the last question is how effective is presurgery, neoadjuvant therapy for pathologic single station and two non small cell cancer, lung cancer. So, this is actually quite a hot topic right now in thoracic surgery. Um, so the, um, with, you know, so neo adjuvant therapy, um, is being trialed now, multiple, multiple trials, I think, like, you know, checkmate trial. And I think there are multiple different, you know, trials around the world and they're primarily, um, looking at, you know, uh, I think immune agents. So, um, immunotherapy as a neo. Uh so before the operation, in order to um reduce the size of the, uh the, the, the um, the uh the, the pulmonary nodule and then as a result, so you do like, let's say, four weeks of neoadjuvant therapy and then you then move to your operation if, of course, you know, n two disease, I don't know if anybody will operate on an N two disease. But, you know, the idea is that, you know, you do the neoadjuvant therapy and then if there's a recession in your uh cancer, then you go ahead with your operation and then you do your adjuvant therapy after that. So that's the sort of, that's right now quite, you know, a hot discussion point in thoracic surgery in, you know, bringing the oncology into the, uh the, the surgical aspect. Really. Um Thanks Patrick. Um Does anyone else have any questions? I think all the questions on the chart has been answered. Um Does anyone else have any questions you can put it on the chat or, or meal yourself if you can, I don't think you have any questions. Thank you very much. I think we are just, um, at the nick of time. Really? Thank you very much, Patrick, that was, um, very well explained and you were able to go, I, I actually thought one hour would be too small to go through every aspect of this, but you were able to get through all aspects of it from the bony part, from the chest wall up until the visceral part of it all in all in the nick of time. Thank you very much for agreeing to, to teach in this session and thank you everyone for attending. Um I would just going to put the feedback form on the chart now. So please please please please fill the feedback form of it's on the charts. Message, send the feedback for only after um filling the feedback form. Will you be able to get a certificate of attendance? And not just to get a certificate of attendance, it will also help the speakers to know how well they can improve in future in future sessions and what we can do better and what we can do difference in in future teaching session. So please fill the feedback form that is provided there. Um And as I mean, as I announced earlier in the meeting, the next um teaching session is going to be next week, Saturday 7 p.m. And it's going to be on um coronary artery bypass graft surgery. So please uh make plans to attend. Um I was trying to get the link to put up on the chart, but I'm not able to get that. But if you go to the um C A me page, you'll be able to see the event and you should be able to sign up, sign up for it. Um Thank you everyone for attending. Please provide the feedback. Thank you, Patrick. And hopefully I will see you guys next week, Saturday. Thank you everybody. Bye bye.