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Hi Iron. Um, let's give it maybe like a couple of more minutes to let everyone join and then, uh, I'll crack on with that afterwards. Ok, let's slowly make a start. So, um, welcome to this tutorial for uh, revising for your, um, MRC S. It's meant to be useful for both part A and part B. Um, obviously, the nature of the examination and questions are different, but the knowledge remains the same. So this um will be on thoracic anatomy. Now, unfortunately, due to the nature of the task itself, it's impossible to cover all of thoracic anatomy in an hour. So WW I'll talk to you about what I'm going to focus on within the next hour, which topics I'm going to especially focus on. But just before I guess a little bit about me as is customary in these talks. So, um, my name is Sai Pena. I'm a uh junior orthopedic clinical research fellow, um at the Southwest London Elective Orthopedic Center. Um, what I've done so far. So, you know, I've gone to UCL Medical School, done my foundation training um in Basildon and Thor University Hospitals. And currently this is my f three year, um I have sat both part A and part B um of MRC S. Um And I don't know what the future holds for me. So we'll see if I go on to core surgical training or potentially think about er you assembly and beyond. So we'll see. So without a further ado uh let's talk about the aims of this lecture. So um firstly, one really important thing here's the QR code to the mentee. Um uh Like questions slides, basically where we'll be doing a lot of interactive work. Now, this these sessions will only be as good for you as how much you put into it. So it's literally open ended questions that you can just text on there. So the more you interact, the like more you're gonna remember, especially because if you get questions wrong or you know, you don't quite sure just give it a go on there and then we can talk about uh what the right answer is and you're more likely to remember it. So yeah, hit the QR code log on to mentee. The code is listed there below. So it's 3115069 and I'll be keeping an eye out um on the mentee. Good. So um what are we going to cover then? So um it's understanding the gross anatomy of the thorax and the individual compartments within the thorax, including the mediastinum. Be able to detail the boundaries and the contents of the mediastinum and also be able to detail the anatomy of the heart and the great vessels. And if you understand the relations between them, and for example, you need to know individually which nerve is anterior to which vessel or, you know, they're in relations between each other. And I think we'll focus on getting those basics, right? One of the key component of thoracic anatomy um is probably the pulmonary system which like I said, you know, unfortunately, we won't have as much time to cover, but let's go through it now. So hopefully most of you are on um ment good. So firstly, so the way I'm going to structure this, um you know, the er this er lecture is essentially um by asking you questions and if you see the mentee app, if you're all on it, um this will be the first question um on there. So let's see if we can uh answer this first question then. So what are the three cavities or potential spaces in the thorax? So, log on to mentee and then have a go basically. So you can start typing in anything. It's fine, just like I said, you know, the more you put in. So what do you think of the three main cavities or potential spaces in the thorax? If you had to divide it up, how would you do? So, I'll give you a moment too or if you prefer, you can put it in the chat as well. Fantastic. So someone's written um media sign and pleural cavity. Yeah. And then someone's written anterior posterior middle. Yeah. So we'll get to that. So the, and if you look at my next slide which is about to load, that will explain everything. So the um person who said the pleural cavity and the median, that's exactly it. So you want to, if you look at that, you have the mediastinum, which is literally the middle area and that includes what the other person wrote, which is superior, middle, all these individual components, which we'll get onto. But either si either side of the mediastinum, you have the pleural cavities and that's essentially it. The thorax is, you can think of it as three main compartments, two pleural cavities and one mediastinum. So which then brings us to our next question, which is how is the mediastinum then further divided? Um So what are the four parts of the mediastinum? So, moving on to the next one and I think you guys sort of answered it already so we can skip past that. So essentially, it's, you have a s Well, I'll show you on the uh on the um diagram, you see hierarchy here. You can then start to split the mediastinum into a superior mediastinum and an inferior mediastinum. You see this obviously all diagrams here er on the right are from teaching anatomy. So the top is uh in green er is the superior mediastinum and below that is the inferior mediastinum. Now, the inferior mediastinum can be further subdivided as shown in the flow chart here into anterior which you can barely see just about here. The a slither of er purple, the middle mediastinum which is obviously mainly contains the heart that takes up most of the space and the posterior mediastinum which is the blue at the back here. Ok. Good. So you have a very good and easy structure to follow. So thorax, I believe actually is making it as simple as possible. So you literally have two pleural cavity, either side media sinum in the middle, media, sinus splits into the superior and inferior. The inferior is then subdivided into three anterior, middle and posterior. Good. Next question. So what then are the boundaries of each of these spaces? Now this is your bread and butter that you know, this can easily come up in both part B but also you'll need knowledge of this in part A to be able to answer the questions. So on to ment, what are the boundaries of the er well, let's do it individually. So first one will be what are the boundaries of the superior media sinum? Let's do that first. So do the four individual components and you can split it when you write it into anterior, superior, posterior and inferior and just give it a shot really however many you can name and I've got good schematics coming up to be able to see it both in an anatomical diagram but also schematics. So just remember, I almost used to remember the thorax and the boundaries as like cuboids stacked up on top of each other or cubes er because that makes it really easy to visualize the boundaries. So if you guys, you can write, for example, what do you think the anterior boundary of the superior mediastinum is or the roof or the floor inferior as the base of the aortic arch? Yeah, I mean, you're not technically wrong. Um Not technically wrong. But what I would say is what does the base of the aortic arch or the aortic arch? What level does that correspond to? And then that will give you your answer. But yeah. Any other, any other boundaries that you can name? Floor pericardial sac, not so much but angle of le Yes. So that we're getting closer now. So superior mediastinum, um superior thoracic aperture. Yes, otherwise known as the thoracic inlets are absolutely correct. Um Transverse thoracic plane T four to T five and then ribs, 1 to 4 ribs, a vertebra, 1 to 4. Yes. So good. Some of you had a go good. Um So we'll show you the diagram essentially. So let's start with the schematic cos that makes it easier. And then you can refer to the um teach me anatomy diagram and obviously teaching anatomy is a great resource they're facing each other. So, the orientation will be a bit off. But if you look here, you have a notch here within uh just above the sternum above the manubrium rather. So this, for example, from the juggler notch to the angle of le that corresponds to the manubrium, not the sternum, just the manubrium. And so therefore, this juggler notch, which is this dip here of the thoracic inlet is the, is the top part and that goes back and it goes to the T one vertebral body, the thoracic, the first thoracic vertebral body. And that's the superior boundary. The roof is an imaginary line connecting the T one vertebral body to the jugular notch. OK. Then let's do the inferior, which is then again, another imaginary line from the T 45 which corresponds to the angle of le which is basically the bottom of the manubrium are otherwise known as the manubriosternal joint. So if you can have a look here at my literal finger, so this would correspond to the manubrium here. And then as it changes angle that becomes the sternum and goes down, so that if you draw a line from there to there, as the schematic shows T four to T five, that's your imaginary line and that's your floor. OK. So all of this is spanning is the manubrium, that's the imaginary line, that's the imaginary line. And this is essentially your vertebral column from T one to T four to T five as one of you guys correctly said, does that make sense? And I've listed it out as well, er, anterior, you know, um superior posterior, et cetera. The difference is for party, you need to be able to imagine it and you know, have it and because it's a multiple choice. Oh, sure, of course. Yes. Um I can go back to, sorry, I just saw that um, one second very quickly. Sorry, I just saw one of the people say, there you go, let me know once you are on it or you say that's enough and I'll move on or if you've got the QR Code. Perfect. Good. So yeah, so um the difference is in part A, you need to be able to visualize it and, and visualize it alone because then you'll have multiple choice in part B. However, you need to be able to say what the anterior boundary is, what the superior boundary is, et cetera. So I would become very comfortable with all of that. OK. Good. Next stop. Um Right. So before we get there, then next question on ment, what are the boundaries of the anterior mediastinum then? So now we're going from the superior into the inferior and specifically of the inferior, we're doing the anterior media sinum. What are the boundaries of the anterior mediastinum? Give it a go similarly. Yeah, give you a little bit more time. So remember the manubrium corresponds to the um superior mediastinum. So what do you think is the anterior border of the anterior mediastinum as you go down. What are you, what did I say? So it's the manubrial sternal angle. And then, so if you're going below that anteriorly and you can see it on this diagram already, what do you think if you had to guess is the er anterior border, the anterior media sign, right? So someone's given it go so good. So roof is the posterior aspect of the superior meter sun, yeah, or the inferior aspect. Um but I know what you mean. Anterior is the body of the gen very good, good. So roof is essentially this same imaginary line. Actually, it's just you can say an imaginary line from the angle of Louis to the P 45 vertebral body. So that's this OK. The anterior boundary would be the um body of the serum very good and the floor very good. Someone else has said or same person actually, who knows is the diaphragm very good. And then therefore, what do you think is the posterior boundary? Anyone? Yes. Uh there's a bit more to the heart. Uh You typically say the fibrous lining of the pericardium because uh the heart is surrounded by a pericardial layer, isn't it? So exactly. But yeah, good. And we can show that now is exactly as you can see here. It's the body of the sternum. That's the same imaginary line we'd described from going from the angle of le to the t 45 vertebra. Um And then the floor is a diaphragm as it spans back er from an anteroposterior direction. And then the posterior boundary is the er anterior boundary of the fibrous pericardium. Does that make sense? OK. And again, I've um put it down uh in writing there for you as well, hopefully makes sense. And these are the nitty gritty. Unfortunately, there's no way around this if you get me. So you have to go through and learn these boundaries. But like I said, visualizing it as like literal cubes and cuboids and almost buildings makes it so much easier. Good. So next question, very good. What are the boundaries of the middle media? So and then, and this is a little bit more easier. Remember by the way, so once we get to the mediastinum, the lateral boundaries, if anyone ever asks you for the lateral boundaries and they might in your part b um will always be what will always be your does anyone want to put it on the chat here? Cos it's not a mean, what will the lateral boundaries of the mediastinum be whether it's the superior mediastinum or the um anterior middle or posterior mediastinum? What will always be the lateral boundaries of the mediastinum? And when we put it on the chart, just give it a go. Yeah, very good. I mean you put it on the mentee er I meant the normal chat but yeah, yeah. Yeah, exactly good. Very good. And then now yes, someone else has er giving it a go for the m er boundaries of the middle medias. So roof as before, perfect good floor as before. Indeed. Um anterior is the posterior aspect of the anterior. Yeah, exactly. Very good and posterior aspect is thoracic aorta great vessels, not quite. So I there's a reason why I said the middle media center boundaries are very easy to remember. Does anyone know what posterior aspect, posterior boundary of the middle media? So is so we said the anterior boundary of it is the fibrous pericardium, anterior aspect of the fibrous pericardium. What do you think is the posterior aspect? Yes, exactly. So the posterior aspect of the pericardium as well, the fibrous pericardium because remember you have and as we will show in a minute, you see that yellow obviously representing where the major organs are including the heart. Well, that's and including great vessel roots as well. All of that is encased in the fibrous pericardial layer, right? So the anterior boundary is going to be the anterior fibrous pericardium. The posterior boundary is going to be the posterior aspect of the pericardium, the fibrous pericardium and simple as the roof as before the floor, as before. Very simple. And we can talk more about the contents in a minute, very good. And finally, what do you think then moving on to the mentee again, what are the boundaries of the posterior media sign. And then, so I'll give you a clue. The roof is the same, the floor is the same. The lateral boundaries are the same because it's the pleura, what are the anterior and posterior boundaries of the posterior mediastinum? And that's the other thing guys to really be comfortable with all of this. And uh cos we were mentioning a lot of anterior and posterior and middle and all that you just need to be comfortable with describing anatomical relations. So, cordal cranial anterior posterior, you know, inferior, superior and stuff. So, yeah, what do you think are the anterior and posterior boundaries of the posterior mediastinum? Mhm Roof and floor as before. Yeah, anteriorly is the pericardium. Yeah, the posterior aspect of it good. And then posteriorly is the thoracic vertebra spinal process very good and specifically very good. Someone else specified. Yes, T four to T five to T 12 good. So the whole thoracic segment very good. And that's it. And it's the same diagram and, and, and as long as you have that, remember, just go through that a few times as long as you have that in your mind, we then can then start to talk about content. And this is where it's a lot of it is bulk of it is proper memory. It's a memory skill, but we'll talk about it very logically too. So what is the next question? Well, and this is the biggest one that there's a lot going on within the superior mediastinum. So, what are the contents of the superior mediastinum? Does anyone want to start giving it a go? There's so many things that you can just start to list a few out. If anyone has a structure and how to remember it, then I'll be all is because I will present you with hopefully a structure that I used. A lot of it was um like I said, a lot of memory, but at the same time, there is a structure and it really helps great vessels. Uh Yes. Yeah. Very good. Yep. If you can expand on what you mean by the great vessels, but yeah, very good. Will other things go through the superior mediastinum? Mhm. So, talking about vasculature, you can specify which great vessels go through phrenic nerves, archer of aorta. Very good SPC. Yep. So, on the note of great vessels, yes, it's the arch of aorta. That's the crucial thing. Um And superior vena cava. Yeah. As in or at least a little bit of it. Not the majority of it. Thymus. Yeah. Very good. Er, thymus. Well, it's sort of controversial thing but like most people say it's in the anterior mediastinum, but in reality, there will be a remnant that's found in the superior mediastinum too. So don't get too hung up on it. You can think of. I used to think about it as half in, half out. Uh Basically, OK, trachea, esophagus, very good and thoracic duct as are very good as it goes up uh to join er, the junction between uh well, the internal jugular vein and the subclavian good thymus, esophagus and trachea. Very good. Uh any other stuff. And otherwise I can talk to you through about my structure. Let's do that instead. So, what are the contents of each of these spaces? Yes, there's a lot going on in this slide. Now, let me take you through it slowly. So the simple structure and I'm sorry that the way I present to you, I will always think that with MRC S and with life, you need knowledge, you need a baseline knowledge. There's no use with rote memorization. I don't believe in that for the purpose of knowledge, for the purpose of the exam. Though, you do need rote memorization. And so to aid that I'll always present to you a way to structure your thoughts. And then the final cherry on top will be uh like I'm a big fan of pneumonics and acronyms. So anything to give you a little hack to be able to make you remember a little bit easier. So the structure that I'm providing here and this is gonna be true when anyone asks you any er aspects of the contents of the superior mediastinum, anterior, middle or er posterior, I want you to think about the arteries that you find there, the veins that you find there, the nerves that you find there, lymphatic system and then other and the other hopefully is a little bit easier to remember. Other includes, for example, organs or other structures. OK. Good. So that's gonna be an overarching theme when I ask you the next following questions of what's in the anterior meter, middle, et cetera. OK. The superior is the most busy. So then how do I split up or how do I remember each of these or you can see each of these have, has a subheading. I know lymph, but the rest of them has a sub heading and these are some sort of uh pointers for me, memory aids. Um whether that's a Pneumonic or just a word. So for example, when I think about the arteries that I find within the superior media, I just think the arch and the vessels that come off the arch of the aorta. And this is because if you think about it, we know where we are with location. Uh with regards to the location of the er superior meter standard, we said it's from the jugular notch to the bottom of like the manuum, which is t 45. Well, what do we know that crosses us there is the art of the aorta and therefore, it's the base and the end of the er the root and the base of the artery of the aorta. So you get the major vessels that's being given off. So those would be obviously the brachycephalic artery, which is obviously I put right, but there is only a right brachycephalic, you've got the left common carotid and then the left subclavian and those are the, you know, so you got the artery, the aorta and then the major vessels that come off it. Then next thing veins. So I use a mnemonic called ABL S like, you know, B LS as in basic life support. So ABL S and just that just generally, just to help me remember each of these. So there's the azygous vein, there's the brachiocephalic veins. That's your major ones there, there's a left er superior intercostal vein and then there's a supreme intercostal vein and I give you the details below on the in the writing here. And you can look through that a little bit more as you go through the pictures to understand. But essentially both of these intercostals. So the left superior intercostal and the supreme intercostal er veins drain directly into the brachiocephalic. Ok. The azygos however, drains into the um superior vena cava directly and that's below the superior mediastinum, that's in the middle mediastinum. Ok? And that's as it joins the brachycephalic. So good, you see what I mean? So there, there needs to be knowledge, but there needs to be some level of rote memorization for the purpose of exam too. So you need to find that balance. So with arteries, it's an artery, they alter and its major vessels with veins. I remember ABL S as a memoir as a memory aid. Rather not a memoir. Um It's Azygos, er, brachiocephalic left Superior Intercostal and Supreme Intercostal bits. Ok. Good. Then moving on to nerves. So I remember CVP S like central venous pressure. Um It's quite silly but, yeah, CVP. S and that again works for me. And that's the cardiac plexus, the vagus nerve, the phrenic nerves which are bilateral. Remember and then everyone forgets this the sympathetic trunk. And there's a few details again that I've added on here. So if you imagine the relations between each other within the superior media, so well, I detailed at the right vagus and again, this is gonna come with looking at lots of diagrams, lots of atlases. Unfortunately, I can take pictures of too many diagrams or uh you know, like I could, I would ideally recommend that you find yourself by a 3D atlas and you look at the, examine the relation between each other in 3d so that you get that spatial awareness. OK. But otherwise, it's gonna be a lot of words for nothing but essentially the right vagus, you need to remember, it goes behind the S VC as it goes down. OK? And it also goes behind the right bronchus as well. And that's obviously not in the superior mediastinum anymore. This is describing its root down into the middle, but just to be aware, whereas the left vagus passes anterior to the aortic arch and then it goes behind the left bronchus. So what you need to remember is the vagus nerves, both the right and left, go behind the bronchi, but the right one goes um behind the S VC. Whereas the left one goes in front of the aortic arch, OK. The left vagus gives off the recurrent laryngeal nerve. Remember that's really important and it does so anterior to the aortic arch. OK. And that's still within the superior mediastinum. And that swings underneath the aorta and it does this to the left of the ligamentum arteriosum left as in lateral. Ok. But again, you need to go through pictures and like I said that we are time limited, unfortunately, but these details will help you solidify everything. As you see, you need to marry up with the words and you need to think the phrenic nerves you need to remember are lateral to the great vessels in the superior media sinum. But then as they go into the middle, they then dive medially, ok? And they go anterior to the hilum of the lung. And that's important because remember we said, what goes behind the bronchi and therefore the hilum of the lung or it's the vagus nerves, isn't it? So the right and left go behind the bronchi, whereas the phrenic go in front of in the hilum good and the cardiac plexus, you can see the details on there. And obviously, you find the information on uh teaching me anatomy too, but essentially just that it's split into a superficial plexus and a, a deep cardiac plexus. And I detail all of that sympathetic trunk, very easy to remember. It's essentially, it runs bilaterally right next to the vertebral column. So it's very posterior in the superior media and right at the back. Um ok. Good moving on to lymph, the thoracic duct is the main vessel really that you need to think about. and it lies to the left of the esophagus as it runs up to join the confluence of the internal jugular vein and the subclavian. OK. Good. And then finally, other, I remember TT O like to take out like uh you know, prescription. So it's simply the thymus, most anterior structure and it runs, runs a little bit into the anterior inferior mediastinum. Um The Rickia er remember it bifurcates at the angle of le which we'll get onto uh and it does sit behind the arch of the aorta and then finally, the esophagus which some of you mentioned. OK. So tt O so thymus, um trachea and esophagus. OK. So remember the structure, arteries, veins, nerves, lymph and other and then have your own mnemonic. If these work for you, great. If these don't, then you think about it. But that's how you do. OK? You do it in layers, you remember your boundaries, you well, you remember how it's divided, you remember your boundaries, then you talk about your content, you do it in this structure, have a little memory aid. Then you dive into the deep spatial relations between each of them. OK. I know that was a lot. Um But we'll carry on then to the next ment question, then what are the contents of the anterior mediastinum? This should be a little bit easier because there's barely anything. And I kind of wanted to split it up because we covered so much in the superior mediastinum. So what do you think is an anterior mediastinum? Does any II know that was intense as well? Does anyone wanna give it a go? Anyone? So we mentioned one of them already. What is in the anterior media standard or you can say not sure. And then I'll tell you OK. So someone said arteries are very good. You're following the structure like I love that. So arteries, internal thoracic artery, yes, perfect uh veins, internal thoracic vein, you're absolutely spot on. I didn't actually mention it because it's paired now, but you're right. Er, nerves, phrenic nerve, not quite, it goes in the middle mediastinum. Um And then parasternal lymph nodes, sternal pericardial ligaments. Very good, very good thymic remnants in Children, very good lymph nodes and fats. That's it. That's it. I think everyone's on it. Very good. So using the same structure and sorry, by the way, this was the diagram to show you er where we are talking about basically. Um and you can see essentially you know, this is the level of angle of er, you know, sternal angle and this, it's until here until this boundary, that's the top of the manuum probably. And so therefore, you have the artery, the aorta, you've got the roots of the great vessels. Um You've got the brachycephalic joining here, obviously, the left coming over, um, the arteries, um, et cetera and you need to see the pictures on teach me anatomy. Ok. Good. And it will all sort of fit in together and then um the anterior mediastinum which wants the next slide loads. That's the posterior. But yes, you're absolutely spot on. So before we move on to the posterior, does er anyone wanna give it a go as to what are the contents of the middle media? ST let's get that one out of the way as well. So what are the contents of the middle mediastinum? But you're all spot on with the anterior mediastinum? Good. Very pleased you're all doing really well. So what does the middle media side of contains following the same structure, arteries, veins, nerves lymph and likely here it's gonna be organs or you know, but yeah, I hope the biggest lesson or at least sort of, you know, message that I want you to take away from this really is I can't emphasize to you enough as to how beneficial is to learn in this structured way where you first uh you know, appreciate the rote stuff like the spaces and the boundaries of it, then you start to think, OK, what are the contents? And you give yourself a structure then a little um you know, acronym and then you then really just spend time looking at models to appreciate the uh spatial relations between them. So someone said, great vessel. Absolutely tia um less. So trachea, because remember where does the trachea bifurcate? So yeah, you said main bronchi are very good. So, trachea bifurcates at the level of angle of le. So once you go below that, you're then in the middle mediastinum. So you're not gonna be having the trachea really uh lymph nodes. Yeah, exactly in the heart. Yes. Very important. Yeah, that's I was waiting for that. That's the big, big dog, I guess in the middle mediastinum, coronary arteries, coronary veins. Yeah, all part of the heart. Obviously, we'll get to that cardiac plexus is a very good uh sympathetic. Yeah, you'll have some sort of synthetic innervation, phrenic nerves, very good arteries. Someone said ascending and descending thoracic aorta, mm Not quite actually, that's in the posterior media sinum. And we'll get to that. The middle media sinum is very packed and it's pretty much remember everything in the middle media sinum or more or less is encased within the fibrous pericardium. So you only have the heart and the roots of the great vessels when it comes to um vasculature. Ok. Bronchopulmonary lymph nodes, very good organs, the heart Yes, exactly. Good. IBCB C. Very good. These are the great vessels good. So, moving on to, I know this goes in a bit of a weird whatever it's supposed to your me. So, and we'll get to that. We'll do middle media sinum first. That's the anterior. By the way, you can see how sparse it is. So branch of the internal thoracic artery for the arteries and it, of course, corresponding for the veins and the lymph, you have minor lymph nodes um and then you have the sterno pericardial ligament because remember you have to an anchor for the pericardium to the sternum to make sure it stays in place good. And now the middle mediastinum er which is exactly so vessels. So you have lateral to medial, uh you know the great vessels and I and if you see lateral to medial, what I mean is if I go back a few slides, you see here, you have the S VC. So imagine here, I know you can't see it on here. You have the S VC most laterally. So right side slap bang in the middle, you have the ar you know root or the ascending root of the A. So it's not quite the arch yet. It's the ascending root here. If you can see uh you know where my cursor is or probably not actually, but you know, next to the er SBC in the grade out bit, then you have the pulmonary trunk, splitting up into the pulmonary arteries and whatnot, er and the pulmonary veins. And so that how I would describe it from lateral to medial. And this is giving you that spatial awareness within the middle media. So it s VC aortic, ascending root and the pulmonary trunk. Ok. Then you have the nerves that I class all of that together as vessels. This time, the nerves, it's just I remember two things which is uh the cardiac plexus and the phrenic nerve. And we talked about the phrenic nerves, didn't we? So um the phrenic nerves are anterior er to the sort of long hilar um that's obviously on the lateral b borders of it. Uh but they just go beside the um heart, essentially um the cardiac plexus. So you get, the plexus gets its innervation from the vagus nerves, which are again, uh more so at just outside the middle mediastinum, more so the pleural cavity media mediastinum border where it goes behind the bronchi, good lymph, check your bronchial lymph nodes and then the organs obviously the heart and you have the bifurcation of the trachea right at the top. You can count whether it counts in the middle media center or not, but you certainly have the main bronchi in there. Very good. Finally, coming on to a busier um cavity again, what are the contents of the posterior mediastinum? And you know, we're pretty much nearly done here with the mediastinum. So you'll be pleased to know that we'll move on to the heart for the latter half of this. So last thing to go with the poster media. Final, same structure, same order. I hope you can see the benefit of the structure. By the way, when you think OK, what arteries are there? What veins are there, what the nerves are there, you start to then appreciate and you start to miss less and this is so much more crucial for Poppy cos you wanna have a systematic approach. But yeah, what are the contents of the poster media? So I gave you a clue of a few things that I mentioned earlier. Are you can uh are applicable now anyone? So remember everything that's in the superior meter sinum, by the way, has to be in the inferior me sinum, either anterior, middle or posterior. So we already talked about thymus. That's the most anterior done. We talked about the heart obviously, I mean that never comes in the superior media center but the great vessels. So what's the posterior stuff? So arteries thoracic a are exactly. Very good and it's branches esoph esophagus, bronchial. Yeah, very good, very good. And we'll get onto that veins, azygos, hemi azygos, very good vena cava. Yeah, uh vagus nerve, very good er sympathetic training. Someone said very good thoracic duct, someone said very good, good. Exactly. And you see how the you know some of this was structured and some of this was a bit of mix of structured and unstructured. And that's why again, if you follow this uh method. So I'm just going back a few slides, then you will not miss it. And then the acronyms or the Onyx will really top it off. OK. So think arteries majority of this is the um the thoracic aorta basically. OK. So you had the descending thoracic aorta and the way I remember it and it, there's no real mnemonic or like reason for this pneumonic is sob p. Um And it's the reason I split up the sob and the p you know, rather than make it BS or something, there's another, you know, message behind it and it's in the writing here. So the key and I'm kind of proud of this Pneumonic myself. So the three at the beginning. So S ob super phrenic oesophageal and the bronchial, that's the S ob are all anterior branches of the thoracic aorta. So they all come off on the anterior part. The p well, that stands for is the posterior intercostal arteries. And as the name suggests, they're posterior and not just that but the anterior three, the supraphrenic esophageal and the bronchial are all unpaired arteries. So they all come off individually. Whereas the posterior intercostals as the names as you can imagine are paired and they come around from either side of the AORTA. OK. So that's the key. That's why the so pea is so beautiful. Um if I say so, myself so good. Um That's the arteries sorted, then the veins. So then you have essentially the Azygos system. Ok. So Azygos system, it's a bit complicated. And again, you can look at pictures and actually the vein as you know, you can imagine, whereas the artery starts at the top and goes down, the veins start at the bottom and merge and then go up. So the Azygos vein is actually formed by the right lumbar vein and the right subcostal vein, it's actually in the abdominal cavity and it pierces via, does anyone know on the chart? Can anyone tell me where does it pierce? Um where does it pierce the, how does it get through the abdominal cavity into the thoracic cavity? Does anyone know the azygos vein? Because everyone I know this lecture isn't on it. But remember there's the, obviously the, you know, the cable hiatus, there's esophageal and the aortic hiatus. So, you know, and that corresponds to T eight, T 10 and T 12. Does anyone know whether uh Azygos vein actually joins um through which hiatus I'll be very impressed anyone or you can say, not sure, I'll give it a little bit more time. Yeah. So it goes through the uh aortic hiatus. T 12 basically. Ok. So that's the Azygos thing, then you have the hemi er azygos in and that's essentially. So if you think about it, uh let me see if I have a slide on here. So, yes. So you can see how the Azygos vein drains essentially the right side of the body. And it's the, it's the big one. And the way I need you to think about it is the hemi azygos and the accessory hemi azygos added together, make up the Azygos equivalent on the left side. That's all it is. So, the hemiazygos mirrors the joining of the, the, you know how it forms, mirrors the Azygos vein because it's the left lumbar vein and the left subcostal vein that join together to form the hemiazygos and it goes in the left side and it pierces. The left cross of the diaphragm drains the left side from about t eight to t 12, roughly or the fourth to um eighth intercostal veins, rather fourth to eighth intercostal veins. And then it joins the azygos because remember it's only half of it and the accessory hemi hemi azygos drains the like, uh, you know, um I think it's the second to the fourth um intercostal spaces because remember on the left side, you have the supreme intercostal veins and the superior intercostal veins that drain the 1st and 2nd space. Ok. So it's essentially one Azygos vein equals one access for hemiazygos and the er hemi azygos. And oh, sorry, I just saw someone said aortic, it is very good, very well done. Exactly. Perfect. So, yeah, for the longest time, I could never understand what the difference is. Between all of these, but it's simply Azygos deals with the right side and it deals with the entirety of it, entirety being, you know, essentially third intercostal space to the 12th and on the left it's, you know, um, er, the hemiazygos and then the accessory hemiazygos put together. Ok. Very good. So the venous system in the posterior mediastinum is quite easy to remember. Ok. Nerves. Then I remember s ap it's quite easy. A sympathetic trunk. Remember, what did I say? Where, where was the sympathetic trunk? In the superior media sinum? It runs bilaterally to the vertebral column, doesn't it? So it's always gonna be right at the back by the vertebral column because that is the posterior boundary of the posterior media sym, that's always gonna be this. So that's the s what's the A and the P, well, the vagus nerve runs in the posterior mediastinum. So not quite the middle mediastinum, as we said, it's at the back because remember it goes behind the bronchi, doesn't it? And the bronchi we said is in the middle mediastinum. So therefore, it's in the posterior mediastinum and the A and the P correspond to the anterior vagal trunk and the posterior vagal trunk. And this will be relevant when we talk about the esophagus, which we will in a minute. So that's s ap lymph. Well, you just have simply more um the thoracic duct essentially forming from the, you know, systemic highly beneath in the abdominal cavity and then that goes, er, up through, uh, again, does anyone know which hiatus it goes through? So, again, remember we have the Vena Vena Caval Hiatus, cable hiatus, oesophageal hiatus and the aortic hiatus. Does anyone know which hiatus, the thoracic duct goes through? Um, you can put it either on ment or? Oh, yeah, someone said, yeah, exactly. Thoracic duct hiatus. Um, with the th, yeah, thoracic ducts and the aorta perfect. Very good, smashing it good. Um So it goes through the aortic hiatus. It's essentially on the right side and then it eventually goes, it's obviously traveling up and then it goes to the left side and we'll talk about where it goes as well. Good. And then finally, the other thing is the esophagus is a very posterial structure. Um One thing you should always do is like I said, go through an atlas and see essentially because the aorta, the descending thoracic aorta also essentially goes, it goes anterior goes, dias goes posterior and it goes laterally left as well. So you always want to know the relationship between these three structures and it's difficult to show on here. But the thoracic aorta, the esophagus and the thoracic duct. OK. So make sure you do a cross section. You see a cross section of the thoracic cavity and you see where they are, that's important to remember. Good. Um And then yeah, anterior vagal trunk and uh posterior vagal trunk around the esophagus, basically. Ok. Good. And it's essentially ralp. That's how I remember it. Right. Anterior, left posterior. Good. Good. Wow. I think that is the mediastinal contents and that's a lot I know. So, really well for sticking it through so far, we'll finish off with essentially um features of the heart, cardiac anatomy. Basically. I suppose the final question before we move on though. It however, is a classic exam. Bread and butter again, again, part A or part B. What is the angle of Louis? Well, we've answered that already and which structures are found at the level of the angle of Louis then. So can anyone tell me which structures are found at the angle of Louis? Start listing a few and we'll get back to it? I am. Thank you. Exactly. Samantha like sorry, II was I keep switching between mental and the chat? So, yeah, aortic hiatus times two. You're right. Er, of aorta. Yep, tracheal bifurcation. Very good. And of course, as we've all kind of been reinforcing so far, this is t 45. Very good. Exactly. Exactly. Otherwise known as the manubrial sternal angle or just the sternal angle. Um manubrial sternal junction. So many names to the angle of lo but yeah, archer veal to tracheal bifurcation. Any other things that you can think of because they will ask you by the way in part B um or even part A they'll give you a clinical scenario related to do with this and they'll, uh, not go for the obvious ones which are obviously the, er, aorta and the tricky bifurcation ever remembers those. Any other ones that you can offer up? Give you a few more seconds. Cos I also realize the time we need to get through a bit of the heart. Cool. No worries. We'll go through that here again. I've come up with my own little mnemonic patty. Um, you gotta bear with me with the, y there's a bit of work that needs to be done. A little leap of faith. But yeah, so here, Pulmonary trunk divides into two arteries. OK? That's one, just a minor one that people don't remember. Arter of aorta. Absolutely. Tricky. Bifurcation. Absolutely. Here. That's what I meant here. The thoracic duct crosses from the right side, slightly on the right side to the left side. Um That's something you need to remember here and then the Azygos opens into the S VC. Um And again, that's an important one too. OK. So I'll say the really important ones you cannot afford to forget. The arch of the is a tracheal bifurcation. Azygos opening into the S VC. Second, most important, I'd say a thoracic duct crossing from the right to left. And then the third most important is the pulmonary trunk divides into two arteries. OK. Good. Um Yeah. Yeah. Yeah, you can talk about the esophagus as well. I mean, there's a point of constriction stuff like that. But no. Um yeah, it's, it's sorry also. You're right. It, it does cross at the level of the T 45 but I meant, I guess typically what happens at T 45. Good. Well, I would love to give you a little break but um well, I'd love to give myself a little break but we're gonna crack on with the heart and then we're gonna do 10 questions, but there's a lot to it. OK. So one moving on to the heart um and the surrounding structures, what are the layers of the pericardium? Can anyone tell me in order we kind of mentioned one of them already, I'll tell you for a fact. One on the most outside of the pericardium is the fibrous layer of the pericardium. OK. So I'll give you for a fact that as you start to go more, you know, internal, what are the different layers that you encounter? So you've got the fibrous pericardium, then fibrous series, which includes the parietal and visceral. Very good, very good visceral also called the Epicardium. Perfect. Did you copy and paste this from uh teach me a or something? Cos that is textbook. Very good. So, yeah, exactly. So um that's the bit that a lot of people get confused is that there is fibrous pericardium and then there's serous pericardium and the serous pericardium is again, individually made up of the parietal and the visceral pericardium. And I've got a diagram to illustrate that, hopefully straight from T three anatomy. So, yeah, that's exactly it. And the visceral pericardium is also called the epicardium because it is right on top of the heart. And so, yeah, exactly. As you can see in that diagram, you can see that and there's a little slither of fluid, obviously um within the serous pericardium between the parietal and visceral layers. And that's why it's called the serous pericardium. And that is also where pericardial fluid accumulates very good. So that's fairly straightforward. Good then. Oh, sorry, I'll move back out of it. So the next question is, well, don't ignore that. Not the rounded edges of the atria. How many great vessels are there? And what are they? So we keep mentioning great vessels. Well, tell me exactly what comes in and out of the heart in terms of great vessels. Let's try and do it as sort of quickly as we can guys, cos we might overrun probably at least by five minutes already so far. And I don't wanna take up any more of your evening. Cos anatomy gets quite intense, quite quickly, especially because there's a lot of imagination, aorta, pulmonary trunk, pulmonary veins, superior, inferior, yeah, very good, very good. Uh superior, inferior, you mean pulmonary veins or superior, inferior Vena cava? Oh, I don't know exactly. So, well, Vena cava is the other one but very good. So there are, I would say eight you know, major vessels OK. Uh two arteries, only two arteries actually, which is quite surprising, which is the aorta that comes out. And then the pulmonary arteries obviously that come out and then six veins, four of which are pulmonary veins that drain in and then you have the SBC and the IVC that also drain in from the top and the bottom. So hopefully, I have a picture to illustrate this. Yeah, there you go. And this is again, remember that this is the middle media standard. Remember like here in, you know, right at the t like the root of the great vessels and below and again, remember just trying to reinforce that lateral to medial. So SBC ascending root of the alta and the pulmonary trunk and you can see that here. Uh But yeah, exactly. So two arteries and uh six veins. Very good. Next question then moving back a slide now. So what are the rounded edges of the atria called? Does anyone know? And that's the thing some of anatomy like I said is Rogue me rote memory. And this is one of those you just have to remember that this is the term that's used for it. Atrial appendages. Yeah. Yeah. Or alternatively, more typically in a more anatomical setting. Anyone. So, yeah, it's oracles, that's what it refers to. OK. Um And these are the internal features obviously of which we'll get onto. So I don't wanna show that yet. Sorry, my apologies. Yeah. Oracle exactly as someone said, good. Um What now? Yeah, before we get onto the other parts of the diagram, what are the Sulci or soul cai on the surface of the heart? What are they like? What are they called? What are the different Sulci on the heart? Well, there are names for them on there. So does anyone wanna give it a go and we'll come back to the atria in a second. Anyone coronary sulcus, anterior interventricular, remember? Er but yeah, exactly, exactly interventricular because it's dividing ventricles. Very good. Atrioventricular. Yes. So. Right. So what is the coronary sulcus alter alternative name? Well, that's it. It's a atrioventricular sulcus. And then yes, the final thing I was gonna ask was the posterior interventricular groove or the sulcus. Very good. Fantastic guys. So good. And then the next question, then what did the soul cai contain then coronary vessels? Yeah, very good. And we'll go through them in detail. But I suppose does anyone wanna, I can go through that quickly, quickly, I guess branch of the coronary arteries? Yeah, exactly. Fantastic. Good. Right. And so now we're going to see the diagram in a second, but before we do, what are the five in the features of the right atrium? So name any features of the right atria and these are the bits that, you know, students often get a bit confused because, well, the names are very archaic and they're they're, you know, Latin based and all of that. So it can feel a bit, you know, overwhelming. But can anyone tell me any internal features also? Remember by the Sulci also contained fat along with the coronary arteries, sa node. Yeah, I mean, you wouldn't be able to sort of see it. It's more like electrical tissue there. Pectinate muscle. Yeah. Very good. Musculi, pectinati, as they say in Latin. But yeah, pectinate muscle. Very good. That's, yeah. Carry on anyone else. What other features would you see or should we go through it? Ok. Let's, let's have a quick, let's go through it. Good. So I'll say there are five internal features of the right atrium. OK. So you have an opening for the S VC and the IVC and of course, the coronary sinus. Now, can anyone tell me what is the coronary sinus when we refer to er, yeah, fossa wallis. That's a good shout. Yeah, I mean now that you can see the diagram, of course, but anyway, I'll give you the benefit of the doubt. Um What is the coronary sinus, by the way, can anyone type on the same mental chat or, or the, or er me chat? What is the coronary sinus in the right atrium? Anyone? It's really important that you sort of get your head around these terminologies and then you'll be fine. Exactly. Drains the coronary veins. Perfect. Good. Cos again for the longest time, I didn't know. So S VC draining from the top IVC draining from the bottom and then the coronary sinus, draining the coronary veins itself. And don't let that get that confused you with the coronary sinus in terms of the arteries, cos that's a different coronary sinus and that's on top of the heart and we'll get to that. So, yeah, exactly. So the five features are so opening of the VC IVC and coronary sinus, muscly, pectinati, there's a muscle of the atria sinus venarum, that's a smooth muscle. And this surrounds the IV CSV C and the coronary sinus. And that's actually an embryological feature. So sinus morum, when it refers to that as smooth muscle, because it actually is incorporated into the heart from the vessels. It's not a part of the actual heart. It's actually as the vessels fused with the heart itself and it became smooth muscle in that sinus venarum. And then you've got the Crista terminalis, which essentially is a muscular ridge that separates the muscular pectinati or the muscular pectinate from the sinus venarum, which is smooth. So essentially, it's a ridge separating the rough muscle from the smooth muscle and that's all it is Crista terminalis. And then finally, yes, the fossa ovalis, which obviously a lot of people are familiar with good. Moving on next question. So we talked about the Sulci, we talked about what they contain. We talked about five anal features. How does this contrast to the left atrium then? So, moving on to the ment he has this contrast to the left atrium and that's the right ventricle by the way before we get to the spoil all that. So we don't wanna go there yet. So, yeah, how does this contrast to the left atrium? What are the features of the left atrium? What's special about the internal features of the left atrium? Well, nearly at the end guys, you're doing so well. I love the inactivity and I hope you're getting a lot of out of a lot out of it as well. So do you think all these features are there in the left atrium? Do you think it's different? You know, for example, are there any pectinate muscles in the left atrium or if so where is a pectinal muscle found in the left atrium? Or even more simply you can type in, do you think the left atrium is more smooth than the right atrium or more rough than the right atrium? Yeah, openings of the pulmonary veins instead of VC IVC? Perfect. That's fantastic, good. So four pulmonary veins. Exactly. Very good. And so remember we had three openings in the er right A, didn't we? The SBC IBC and the coronary sinus? Whereas in the left A we have four openings. So do you think the left atria is more smooth or more rough compared to? Yeah, smoother than the right atrium? And why is that? Well, it, it's contributed to the embryology and that's what I said right, the sinus venarum, the smooth part of the smooth muscle of this er atria is derived from the vessels, not the heart. So more openings that there are some more veins draining into this, the more you know, smooth. Um the left atria is very good. And where is the pectinate muscle found? Well, actually it's found within the auricle of the left atria. So they actually within the outer folding of the left atrium. That's where the pectinate muscle is found. And that's why it's even more smooth inside. Good. Then, as kind of the picture is spoiled, moving on. What are the features of the right and left ventricles? So what are the internal features of the ventricles instead, you see guys, the thoracic anatomy I believe is actually really easy once you wrap your head around it and you guys are doing so well. So what are the internal features? Obviously, you can go into very much a lot of detail, but I'm focusing broadly sort of the high yield stuff. So there, I'll tell you there are three main features. What would you say there are, they are and we're nearly at the end, papillary muscles, cory, tendon, bicuspid and tricuspid valves. Yeah, I mean, obviously the valves obviously separate the um atria and the ventricle. So, yeah, that's another whole different topic. You know, you can talk about the leaflets of the valves, you know, anterior, you know, er posterior, um septal, all these kind of things. So that's again, something I think can't physically cover within the scope of this, um, you know, study, unfortunately, this study, this, er, tutorial moderate band only in the right ventricle, not in the left ventricle, not sure quite what you mean by that moderate band. But, yeah, so papillary muscles and tendon are 100% include and then there's one other feature what makes up the big. So if there are pectinate muscles in the r er atria, what muscles are found in the right and left, the PPI muscles remember are simply attached to the Cordy tendon to the walls of the atria uh to to the walls of the ventricle. But the real bulk of the muscle of the ventricles is formed by and yeah, exactly. Someone said Trabecula Carni and I guess the Carni is very vivid, isn't it? It Carni is incar you can think about it as very much muscular. And that's exactly what I'll illustrate in the diagram here. So you can see exactly here that you know, the really muscular aspects of the trabecular Carni, the papillary muscles will then attach to the walls of the ventricles and then from the tips of the papillary muscles, you have the Cordy tendinae which then attach the leaflets of the valves to prevent them from prolapsing. Fantastic, moving on. Finally. So yes, before we get to that, the final couple of questions are describe the Coron arterial coronary system and its branches. Well, that's a big question. I know. So, how will you do it? So, can anyone tell me the, you know, er, right coronary artery system, how does it, you know, describe essentially the route? Where does it come off, then? What's the major vessel then? What's the dominant circulation in the majority of people? And therefore, what vessel is formed? Can anyone give it a quick bash in the last, like, literal two minutes and then I'll call it a session. OK. So you've chosen to completely ignore. I said about the right. I'm joking. You go to the left, which is completely fair. So, yes. So left coronary artery, you're saying then left circumflex le L ad left marginal. Yeah. Yeah, I know. Yeah. So first remember you have the left coronary sinus. That's your first port of contact, your first origin. Then you have the left main stem that then gives off the L ad left circumflex and the left marginal et cetera. Very good. And then the right anyone. It's a little bit simpler, right? Er RTA. So yeah, again, I want you to remember you gotta be paying attention to the details. It's the right coronary sinus. Then the right coronary artery is given off. Then you have um yeah. A sa sinoatrial nodal branch. Yeah. Very good. A right marginal branch. Very good. Um Well, if you're talking about the sinoatrial nodal branch, then what about the um what about the other node. And then what about the marginal branch? And then what does it go on to become? Because like I said, what's the majority and the majority of people? What's the dominant circulation? What forms the posterior interventricular artery? Yeah, exactly. Posterior to ventricular branch, which is the right coronary in, you know, most people, I think it's about 65% of people. Ok. Very good. So it's atrial node or branch. And what about avian, the atrial ventricular node? What, which artery supplies that then? Oh, which system rather? Yeah, exactly. You know, and then the right, it's basically, well, pursue descending b so you have a branch of the right coronary artery. It's the right coronary system. Good. That's the arterial system. Well, now it's slightly trickier because everyone not, does not pay attention to the venous system. So how would you describe the venous system that drains the heart? Then everyone always remembers the arterial system. Can anyone list me any veins that they know? And where does, where do these er, veins run? I always wanna think about them as like accompanying the arteries because they do run in the same sulci. So I always wanna, if I say a vein, I always wanna think about the partner artery basically. So does anyone know any veins and where do they go? Yeah. Great. Middle, small. Yeah. Yeah. Yeah. Yeah. So you actually spot on so great cardio vein, middle cardio vein but doesn't even know the uh root, I guess I'll go through it with you. It'll be easier. So you can see the photo or the, you know the diagram in a minute of the venous circulation and you see the posterior aspect of it, which is good. The great cardiac vein runs in the anterior interventricular sulcus or the coronary sulcer. And it's, I say it's the equivalent to the L ad the, you know, left anterior descending artery and it wraps around because remember, you have to remember, it starts at the bottom and it goes up and it wraps around and you can see it wrapping around in the bottom picture here and it then goes into the coronary sinus. OK. And it runs in the posterior atrioventricular sulcus. Now the middle. So remember the great cardio vein that's equivalent is the L ad. If you remember that, then you remember exactly where it is and you can identify it. Ok. Then the middle cardiac vein that runs in the posterior interventricular sulcus, then you can imagine is the, the equivalent is the posterior interventricular artery and it goes straight into the er the coronary sinus sulcus as well, the Coron sinus. And then finally, you have three sort of anterior cardic veins that drain the right ventricle and they drain directly into the right atrium itself, which you can see here. Ok. Um In, in the top picture here and that should be vast majority of the structure of the heart. Well done guys. This was a whirlwind for me to get through. Uh, I think, um, first we'll send the sort of feedback link. So please, I would appreciate if you could, um, fill it, give us a little bit of feedback before you go. I'd really appreciate it. I hope you've got something out of it. Um, good luck for your exam if you do have anything booked my email is there if you want to email anything. Um Like I said, I just simply did not have time to go through. You know, there's so much m many more aspects of anatomy, thoracic anatomy that I would love to go through, including the pulmonary system, which I think can be confusing as well. So, yeah, if you want me to potentially do another session or, you know, you've got specific questions uh or even general advice about how to revise uh feel free to email me. Um And thank you, Samantha. Thank you so much. Yeah. And uh sh us if you're there, would you mind doing some feedback or getting some way to organize it, getting some feedback? But perfect. Thank you so much guys. Or if you have any questions right now, all feel free to ask. I am happy to stick around for a few more minutes. Um So let me know. Hey, um sorry, thanks so much for that. Just give me one second. I'm just trying to get the feedback. Uh on the chat. It's just give us one second. Of course, of course. Thank you. Yeah, I will, I will try to do the lungs as you can appreciate it in an hour. This was impossible to fit in, wasn't it? So, yeah, I did my best. Um, yeah, I would try to do the one. So yeah, I've put the feedback uh in the chat. So please set us uh the feedback again. If there's anything that you find, uh which was beneficial, anything that you think uh we can improve on, uh.