Diaphragm (anatomy)

[Music] this week I thought we talked about the diaphragm I was giving a lecture on the ability of the lungs and the respiratory tree and stuff this week in which we talked about how the diaphragm develops because it's important in separating off this original single cavity to the embryo has into two and then in the lungs of developing and stuff and if it doesn't separate off if the diaphragm doesn't form you get problems anyway we're not doing embryology all we were doing in that aney so let's do the anatomy of the diaphragm because we haven't done it before I've got some I got these by I've also got this model here which is quite nice it has a diaphragm on it so we should talk about we should talk about its functions because I'm sure you know about the diaphragm and its role in respiration but it does other things as well we should talk about its structure it's being in anatomy video babe it's after if we didn't structure again it's a muscular tenderness thing where it's attached the three big structures that pass through it how they pass through it how it's attached to things I'm going to talk about this innovation and this blood supply sounds pretty thorough right or chucking some clinical smatterings towards the end [Music] so the diaphragm is a it's like a domed thing is kind of a double dome really and it's you know it's it's it's up in here within the ribcage and as I saying this it's mostly muscular with this central tendon and we'll talk about the different parts as we as we go but the that double dome by the way we're a couple of weeks away from yet another exams because there's lots of students studying if you hear noise its students studying this is in a very soundproof room I don't got a saying proof room anyway I'll just try to talk over so this double dome the muscles contract and the dome flattens somewhat and you guys you're probably I imagine you know out jogging or anything while you're watching this video if you are go check the lampposts you're probably sat down not burning a lot of energy if your diaphragm is gently rising and falling and that is your main muscle of respiration it's the main muscle of inspiration so when this dome this can fall partner when this dome pulls down and flattens the volume inside the 4x increases with that increasing volume is a decrease in pressure so to equalize that pressure is drawn into the lungs when the expiration it's mostly the diaphragm present we ever do most the diaphragm relaxes and the the muscle of course the the lungs are very full of elastic material so when you exhale it's a very relaxed action because the must be the lungs shrink the diaphragm relaxes and so on which is why we say that the diaphragm is the main muscle of respiration because it does inspiration and then the United agent makes you breathe out so the diaphragm flattens somewhat during inspiration increasing the volume in the thorax and if it increases the volume in the thorax then it's gonna have to push down on the Timlin so the volume of the abdomen kind of increases a little bit of course we haven't got the ribcage down here which means the abdomen can change its size more easily so when we talk about belly breathing what we're talking about is that is the diaphragm pulling down and flattening and pushing all the the contents of the abdomen act way if you look at if you watch cyclists in the Tour de France was something similar these super skinny guys you know they're crazy crazy lean guys but has they going up a mountain and breathing through their ears you'll see they develop a belly the reason they develop a belly is because they're breathing so hard they're pushing their abdominal contents and of course they're hunched over a little bit oh my god we really got a lot to like her on right so they they look like they're developing bellies but they're not that belly breathing so it's the diaphragm moving down now if I take the lungs off here you can see quite clearly that the heart in fact surrounded by pericardium sits on the the center of the diaphragm which means actually that double dome shape of the diaphragm is somewhat flattened towards the middle where the heart in his pericardium lie upon it and under here we have the liver and the liver is kind of pushing the right dome a little bit higher than the left though but all of these things are this is the plastic model that doesn't move but you've got to remember that in biology as the diaphragm is moving all of these other things are moving as well so the heart is going up and down the livers being pushed down the stomach so over here the lungs are obviously changing in size and that sort of thing so there are no spaces in here everything's packed together so as the diaphragm moves the liver gets pushed down the heart gets pulled down and then everything goes back up again which means that if you're trying to you know if you're trying to image this area if you if you if you stick some of the MRI scanning Neutron images there it's very difficult because everything's new moving nothing stays still for long enough anyway oh so the other important effect then of the diaphragm is that if it pushes down into the abdomen you can use it to increase your intra-abdominal pressure or your intra abdominal pelvic pressure which is very useful when you're trying to squeeze things out of the abdomen on the pelvis like vomits and feces and babies and things like that I was in the gym this morning wasn't expelling vomit or feces but I was always doing leg day to day so I was doing deadlifts and what-have-you and you get really at a breath it really hurt partly because you're using massive muscle groups but partly also because you're using the diaphragm to increase the pressure in your core in your trunk to make a you know a solid thing that you can use to lift heavy weights which gets you a bad breath you know so you're kind of you don't I know some people hold their breath / female you kind of increase the pressure so the abdomen the the diaphragm also gets used in in controlling and increasing the abdominal pressure for lifting heavy weights expelling things from the abdomen and the pelvis and that sort of thing okay that's that's functions any other functions hiccups laughing related right all right structurally then the diaphragm is muscular around the periphery and more tenderness towards the center so this central aponeurosis it's kind of flattened tendon that we see here it gets called the central tendon of the diaphragm and you get an idea here you can see three things passing through the diaphragm at different levels we'll we'll meet what each of one of those in turn but the diaphragm then is it's anchored in here and essentially it's anchored to the inferior six room so ribs seventy nine ten eleven twelve and the zipper we process and the a vertebrae down here and a different pass get described the other thing I want you to think of is that inside the formax here it's not a neat oval remember that the vertebrae are pushing outwards and T really into the thorax which means they're the shape of the diaphragm also isn't like a perfect oval it is then instead that shaped right so that means yes that sort of shape all right I wanted to keep that in your head when you're thinking about the diaphragm and the shape of the posterior thoracic wall so there are four parts of the diaphragm if we have that central tendon the diaphragm is anchored anteriorly by a sternal part which attaches to the the inferior surface of the zipper we process is as if we process of the sternum here and then it has a costal part this bit running around here and this part of the diaphragm is anchored to the costal cartilages and the ribs of the inferior six ribs like I said so posterior we have these floating ribs 12 and 11 we have seventy nine 10 11 12 right so it's anchored to these ribs heat and then postie really it's anchored to the first two or three lumber vertebrae there seems to be some variation here and in here we find the medial and lateral arcuate ligaments we'll talk about those in a moment which is anchored to and here we find the Kura these two long slips anchoring the tendon and the diaphragm posterior so there we have external parts the costal part costal referring to ribs and then we have the lumber part anchor to the lumbar vertebrae all right okay so posterior we've got some interesting stuff going on what do we got well you know how muscles are wrapped in fashion and layers of the body are kept separate by layers of fashion right here this is this is so it's major flex through the hip running from the vertebra down there there's quadratus lumborum again running up to the vertebra over there now these guys are covered in fashion and we're about a fashio thickeners they form what we call our qubits ligaments arcuate arching may be the because of the way I can't see it here because it's deep to the kidneys but has these go up here the the solar sorry the quadratus lumborum muscle is covered by the lateral arcuate ligament and the psoas major muscle is covered by the medial arcuate ligament and so that's the flasher forming a thickening up under here somewhere and those thickening those arcuate ligaments act as anchors for the diaphragm and the anchors are here these are the Qura the left and right cross these are muscular structures running from the first couple of lumbar vertebrae and they're running up to form the posterior to anchor the posterior part of the diaphragm here and look you can see the aorta running between those two crew running in the gap there so those are the medial and lateral arcuate ligaments now where the two crooler meet here where they come together that gets called the median arcuate ligament median being in the midline so lateral medial relative to one another median being in the midline well pretty much the midline anyway so that's the median arcuate ligament there and then these two you can see the crew the the left and right screws of the diaphragm running up and then inserting against the central tendon up here now there's the esophagus there can you see the direction of the muscle fibers so the muscles of the so the right cross is that it's fibers of running over that way and the left cross left right the left cross is running over that way so the muscle fibers of the two crew are also forming another gap for the esophagus this is the esophageal hiatus and it forms kind of a bit of a sphincter but you know a really good swing trees like a ring of muscle and we haven't really got a ring of muscle there we've kind of got a ring of muscles we've kind of got a reasonably good thing to hear and that esophageal hiatus along with various other physiological things and other structural things where the esophagus meets the stomach forms a reasonably good sphincter between the esophagus and the stomach stopping stuff in the stomach from going back a bit at the esophagus it doesn't work very well to get reflux acid reflux gonna pin to the esophagus there cause may be a pain when you eat an thing right you might take antacids for it so that fast wine that problem occurs is because there's not a proper thing to there there's like a reasonably good one so this is softer GL hiatus get squeezed when the diaphragm contracts so the aortic hiatus is actually a gap between the two crueler movements of the diaphragm don't affect the aorta I think the esophagus passes through the esophageal hiatus the movements of the diaphragm do affect the esophagus then here there's another hole there in completely the pink part the model apart but that is the hiatus for the inferior vena cava and look because the heart is sad and its pericardium is anchored to the diaphragm that the inferior vena cava passes through the diaphragm and then it's straight into the right atrium it's straight into the heart there and I'm red very things about how movements of the diaphragm affect the inferior vena cava I mean there was the idea that because the inferior vena cavas attached the diaphragm that actually holds the inferior vena cava open it makes it easier to draw blood back well that sort of thing movements of the diaphragm changing the pressroom pressuring the thorax also help draw blood back into the thorax right but anyway I also read some conflicting stuff about how maybe anyway forget it forget that right so the one thing that we asked students to remember is the levels of each of these hiatuses and the vena cava has eight letters and the hiatus of the inferior vena cava occurs around the level of the t8 vertebra the t89 intervertebral discs where t88 letters write the esophagus if you spell it with a British spelling Zoe s opha software AG us that has ten letters and that passes through the diaphragm at around t10 vertebral level and the aorta has got five letters so that a part is through the diaphragm ur about t12 level sorry in more perfectly / you know right 8-10-12 a or take hiatus a ort i CH i-80 us a or take hiatus would work that's got 12 letters i mike is confusing you sorry so this gets called the the cable opening is esophageal hiatus and the aortic hiatus those are the three big structures that pass through the diaphragm now what about the little structures that pass through the diaphragm through the same holes there is another little hole as well somewhere but I'll meeting that up to you you can work out what I mean what what big cranial nerve ones with the esophagus right for example because that goes anyway right blood supply blood supply will explode blood supply well most straightforwardly well okay first concept is that the superior diaphragm has some blood vessels and the inferior diaphragm also has some blood vessels so the superior diaphragm receives some superior phrenic arteries which are branches off the aorta which makes sense it also receives it also receives the internal thoracic artery x' are running right down down here right on the the internal thoracic artery is running on the internal surface of the thoracic cage and those give off some pericardial phrenic and muscular phrenic arteries to the superior part of the diaphragm so the inferior surface has inferior phrenic arteries and those can come from the aorta or they can come from the first anterior branch of Yale to remember these three guys supplying blood to the GI tract so the celiac trunk is here supplying blood to the foregut that can also give off inferior phrenic arteries so inferior and superior phrenic artery supply blood to the diaphragm and they can come from number of places right venous drainage is similar you have inferior superior for any veins and those can drain directly to the inferior vena cava they can drain to the azygos and heavy as I go say no to use I go system and stuff like that I think they can drain to the the renal veins are back the inferior vena cava but you know you get the idea drains to the inferior vena capable that's I got some of these I got things they go up to the superior vena cava phrenic the thing friend phrenic friend friend thing kind of refers to the mind right freeing Franny friend that's all word freak how does friendly both refer to the accounts to the mind to the mind and to the diaphragm well not sure it certainly seems to come from the ancient Greeks in the Asian Greeks weren't terribly terribly sure either there were a couple of different camps the ancient Greeks had a great time philosophizing working out what was going on in the body right and they believed or some of them believed Plato and Aristotle maybe some of them believed that there were two souls you kind of had your spiritual soul in your physical so I'm immortal sold in your mortal soul and mere mortal soul was up here and your mortal soul you say spiritual soul up here and then you know your physical sold was down here so the diaphragm played a role in keeping the mortal soul away from the immortal soul it's a nice idea I like that so immortal soul freeing friend a being related to the head and what have you and they also talked about the heart you know the heart being kind of the seat of emotion the seat of their consciousness to the seat of that immortal soul the spiritual soul which you can kind of imagine with the motion of a small thing right whereas down here in the abdomen the abdomen is involved in a very physical mortal things it digests food and expels waste and that sort of thing you wouldn't want that to muddy the spiritual stuff up here so they have the word pH re and E and even that of course is is you know an anglicized spelling it's not the ancient Greek is it but how would that be pronounced freeing a friend a friend Franny for I mean I think so ancient Greek and Latin do we really know how we were spoken because of course there are no recordings from that time but that's why the word phrenic relating to structures of the diaphragm also gets related to structures of the mind because of that ancient Greek idea they have some of the Greeks disagreed with that and they thought the diaphragm did the things that it does but it's always good to discuss these things in it right and that leads us to the phrenic nerve doesn't it so the nerve that innervates the diaphragm is the phrenic nerve the interesting thing about the phrenic nerve is actually comes from the neck see 3 4 5 keeps the diaphragm alive we say because it's mostly C 4 but C 3 4 5 spinal nerves come together to form the phrenic nerve and the phrenic nerve pops out between the scalene muscle only going in here so the phrenic nerve pops out from between the scalenes there are three muscles running from the cervical vertebra that's the first couple of ribs but you typically describe the the phrenic nerve is being found on the anterior surface of the anterior scalene muscle then it runs down into the full racks and wherever we're dissecting we often find them blending with the fibrous pericardium is we dissect the fibrous pericardium we find the phrenic nerves so the right right for any nerve runs over the right atrium excited to get down to where the inferior vena cava is passing through that cable opening and the left one pass is kind of over the left ventricle to get down to the diaphragm and they do pass through the diaphragms they innervate both surfaces so the finding nerve is the motor supply to the diaphragm so if you if you damaged one of the funning nerves on one side there will be paralysis over hemidiaphragm there'd be paralysis of the diaphragm on one side which is not a good thing but that also explains why because their sensory also from the diaphragm from the fibrous pericardium and this is the pleura around here like the mediastinal pleura pain from the diaphragm can get referred up to the shoulders you I'm sure you're all runners right you've run a lot maybe have had a stitch in your time the stitch may be related to the liver hanging off the diaphragm and the pain is is is localized maybe they start with but then it moves towards the shoulder well the periphery of the diaphragm the muscular periphery around here is also innovated by the intercostal nerves in between the the ribs and also the sub costal nerves down here so the periphery gets innovated by by those as well as the phrenic nerve and those carry sensory stuff back but you get pain locally but then you seem to get pain up to the shoulder and the reason why is because as the diaphragm gets irritated the phrenic nerve carries that sensory innervation back up here to the spinal nerves of the neck and the brain perceives that pain is coming from the nerves of the shoulder region which are also coming from shoulder perceiving visceral pain is difficult perceiving somatic pain and sensation is very normally we've grown up and do anything how to do it alright nerves arteries but we get in there yeah so now you know the shape of the diaphragm you know it's four parts those are the kind of four parts got more than four parts but you know I mean the three anchoring regions and then the the central tendon we've talked about the three big holes in it and the three big structures that pass through it leaving you to work out where the little structures are it talked about having moves and its functions its innovation its blood supply all right hopefully that was helpful a few clinical things then we talked about a hiatal hernia or hiatus hernia so yeah I talked about esophageal reflux didn't I but if the esophageal hiatus is is really not working very well then abdominal pressure can actually push the stomach or part of the stomach rather and the inferior part of the esophagus back up through the esophageal hiatus into the end of the thorax which makes that whole reflux thing even more likely causing more pain faster a hiatus hernia and that's because we haven't got a brilliant sphincter there congenital diaphragmatic hernia that was one of the things I was leading towards when I was talking about the embryology of this so if so the diaphragm embryologically forms from one for arts really coming together and if that doesn't work properly and there's a gap left in there then there's the contents of the abdomen are forming in the contents of the thorax are forming the contents of the abdomen tend to win because they grow larger faster and they push up into the thorax and they fill the space up here passing through that congenital diaphragmatic hernia and that's terrible because the lungs will grow to fill the space that's available to them so if there isn't space available to that and that lungworm develop so that's bad other kind other hiccups how many hiccup that's here how's your diaphragm spasming that's that's the new a nicer clinical thing not so nice if you have permanent hiccups I suppose right there you go then the diaphragm Anatomy off see you next week you ever don't see you in the vlog before them [Music]

Channel: Sam Webster

Views: 247,629

Keywords: human, anatomy, diaphragm, phrenic nerve, phrenic, central tendon, respiration, thorax, superior phrenic artery, inferior phrenic artery, arcuate ligament, aortic hiatus, oesophageal hiatus, hiatus hernia, hiatal hernia, caval opening, inferior vena cava, aorta, oesophagus, Sam Webster, Swansea, dontbeasalmon

Id: JxHa_-au_3Y

Length: 24min 47sec (1487 seconds)

Published: Tue Jan 15 2019