Medical Transcript - TurboScribe Recording (PDF)

TurboScribe Recording (1/16/2025, 11:08:44 AM) Transcribed by TurboScribe.ai. Go Unlimited to remove this message. So the first thing to note is that there's no valves in the vein straining the cranium and other structures in the head and much of the neck. So there's no mechanism that can prevent t...

TurboScribe Recording (1/16/2025, 11:08:44 AM) Transcribed by TurboScribe.ai. Go Unlimited to remove this message. So the first thing to note is that there's no valves in the vein straining the cranium and other structures in the head and much of the neck. So there's no mechanism that can prevent that flow of blood through the venous system other than gravity. That's what prevents that flow. If you stand on your head, the direction of the flow of blood is reversed. And because there's no valves, it becomes very important to note that there are direct connections between veins that are draining blood from the nasal cavity and veins which also drain blood from the brain, specifically veins that have connections to the cavernous sinus, and veins that drain the superficial structures of the face, specifically any structure in the face whose veins drain to the facial veins are interconnected with the veins that also drain to the nasal cavity. And this gives rise to a phenomenon which used to be way, way, way more important by less important than that. The key message here is that if you get an infection in your nasal cavity or in the cavernous sinus, and if that infection gets very bad, it is possible for the bugs and all of those bacteria to migrate, retrograde to the venous system and enter, for example, the cavernous sinus, which are two very different types, which lie on either side of the thymus and which are responsible for the deep veins which drain blood from the brain. So that if you have infections contract from the nasal cavity into the cranial cavity, and not just the extracellular part of the cranial cavity, but into the central nervous system itself. So infection contracts from the nasal cavity to the central nervous system by passing through veins which have no valves. In terms of the superficial drainage of the face, there's an area here which is referred to by dermatologists and other clinicians as the danger triangle of the face. Why is it dangerous? Because you develop, maybe not you, but one develops pimples in this area here. One develops pimples. And one sometimes pops one's pimples, one does. And when one pops a pimple, you can dissolve why. So as you squeeze the pimple and it just squirts out and hits the mirror, it also squirts in the opposite direction. So half of the junk in the pimple goes onto the mirror and the other half just gets spread into the interstitial tissue around where the pimple had developed. And the bugs that cause those pimples can enter the venous system through the veins that drain that area of the face. And they are directly interconnected with the veins that drain the nasal cavity, and those veins are directly interconnected with veins that drain the cerebral cavity, if you like. And therefore, if you continually pop your zits like that, what can happen is you end up getting an infection that can track back into the central nervous system. Once upon a time, pre- antibiotics, those infections were life-threatening. You can't open up somebody's brain and access the cavernous sinus and clear out the ashes from it. It wouldn't be worth it. So antibiotics have largely got rid of this concept of the danger triangle, but it still exists as a reminder of the fact that systemic veins in the nose and in the face have open, valuable communications with veins that are contained in the cranium and which drain the parts of the central nervous system. Now, where we have arteries and veins that closely approach the surface, the arteries and veins are complete. I told you yesterday that the mucosa overruns the pharynx and in the alveolus is very rich with a vascular, dense venous vascular precipice underlying it, which is used for heat exchange. There are also, all those arterial vessels I showed you also feed small arterioles, which are very superficial in the nose. They lie just underneath the mucosa of the nose. And sometimes you do things like you take your thumbnail off your nose and have a little pull at something in there and you grab something and you pull it out. Or if you look on the underside of your seats, some people stick them on the underside of their face. If you have a look over there, you can see an aneurysm or the accumulated nasal, dried up nasal secretions. So it's nice to think about. If you do that, sometimes you can damage either the veins or the arteries that are present just underneath the mucosa because they're easy to disturb because they're so superficial. And when that happens, you get something called a nosebleed. But the proper word for a nosebleed is epistaxis. And nosebleeds are generally trivial. People get them spontaneously. Sometimes you have a big sneeze and you get a nosebleed. Sometimes if you have certain illnesses, you can get nosebleeds. For example, measles. People get measles often and have nosebleeds during the course of the disease. And generally, nosebleeds are not actually a huge problem. So 90% of nosebleeds actually originate from the septum of the nose. And they originate on the anterior aspect of the septum. It's very close to where the areas are. And specifically, they originate generally from an area which is referred to as Liddell's area. Sometimes called something else. That's just the way the acronym is right. So Liddell's area. And Liddell's area is an area of arterial anastomosis between the steno-palatine, the anterior eduloidal, and the palatine arteries. And these types of nosebleeds are 90% of all nosebleeds. Nosebleeds originate in Liddell's area. And characteristically, they occur in younger people. Particularly children, that comes from nose picking. And then younger people your age, it's generally trauma or secondary to some sort of inflammatory process that takes place. They're easy to deal with. Almost all times, when you have a Liddell's area of need, it's just a matter of tipping your head back and holding your nostrils shut until the vessel that's been damaged, that seals, which it does, and clots, blood clots very rapidly, and then the nosebleed goes away. And characteristically, you would know that you have an arterial need from Liddell's area if you tilt your head forward and if the blood runs out of one nostril, as opposed to running out of both nostrils. So that's classically how you would identify a need from Liddell's area. So generally, not a big problem. In a small number of individuals who have weak vessels in Liddell's area and suffer repeated nosebleeds, it may be necessary to do a small bit of cauterization around the Liddell's area, where you cauterize off smaller and asymptotic vessels. And that tends to stop a recurrent nosebleed. The other place where you can get nosebleeds is in an area at the posterior aspect of the nose called Butreus Plexus. Now, Butreus Plexus is a venous plexus, although most people would accept that the concept of Butreus Plexus, there definitely are vein factors that can demonstrate it by dissection. But when people talk about bleeding from Butreus Plexus, they may also include bleeding from some arterial vessels that cross over Butreus Plexus, in particular, the spinal palatine artery, which is damaged. People who do get bleeding from Butreus Plexus tend to be older. And the patients are much more difficult, not difficult. Some of you will write that down in an email and say, why is it so difficult? Well, I'm not going to do that. I'm just going to tell you where it gets more difficult. Okay, so difficult, more difficult. Now, why is it more difficult to deal with? Because it's in the plaque of your nasal cavity. If you want to try and stick a finger up there, you go for it. You'll have better luck with a pencil, but it's not going to be very pleasant when you get the pencil back there. You'll have even better luck with a barbecue skewer. You'll definitely get that back there, but it isn't pleasant. You didn't like to have to do it. And the second thing about it is that when you bleed from the posterior aspect of the nasal cavity at Butreus Plexus, the blood tends to flow not out of the front of the nose. It flows backwards into the nasal parents, through the nasal colony. So the blood ends up flowing down your throat. Now, that's fine, except you're not designed to have a constant flow of liquid dripping down constantly, a large volume of blood from the nose down, dripping down from the nasal parents into the oral parents and the parents. So very rapidly, particularly when you've untreated bleeds, people can start to choke on the blood. And that then becomes an issue in itself. You'll see a bit of choking later on. If you ask a person who has one of these posterior bleeds to send their blood forward like that, what happens is you get a cochlear immune bleed out of both nostrils simultaneously in general. And for some people, the bleeding can go on extensively. It can go on for several hours, which normally is what will bring somebody to the emergency department. And then when they get into the emergency department, the first thing that you're going to have to do is you're going to have to pack that area to make sure that you try to stop the bleeding. Even before the local myelodermatologist comes in with all their fancy endoscopic equipment to cauterize their vessels. So what you end up doing is you have to take a long thin thing and grab a little bit of string in it. And you pull the string deep up through the person's nose and into their nasal parents. And you allow a hand out from the back of their nasal parents. And then you ask them to open their mouth. And you put a little thing in, grab a piece of string, and you pull the string out of their mouth. And then you attach some gauze covered in Vaseline to the end of the string. And you pull the string. And the string goes up the person's nose and scrunches up that posterior nasal cona and blocks up that area and stops the bleeding down from the nasal parents. And thereafter, later on, when the EMT guy comes in, they will remove that nasal packing and then they'll cauterize the vessels in that area without additional bleeding. So that's episapsis. Nosebleeds. Generally trivial. Sometimes not so trivial. Now, we're going to want to do the next place where air is going to pass. Through which air is going to pass. It's coming through the nostrils. It's passed over the respiratory area. Over the olfactory area. Across the turbinates. Between the turbinates and the neocytoses. It converges at the back of the nose. As you can see, there's a structure, two structures called nasal conae. And then it enters a structure called the pharynx. Now, the pharynx is just a muscular tube that hangs down from the skull. So it's like a sock. And the sock is made up of three principal parts. And these are called the pharyngeal constrictors. And they do exactly what the name suggests. When they contract, they constrict the pharynx. Or the throat, in another word, because you can use it as a pharynx. So they change the diameter of the pharynx when they're constricting. And the three constrictors are the superior constrictor, the middle constrictor, and the inferior constrictor. Which are illustrated on the slide. And the inferior constrictor is the pharynx. Each of the constrictors is a muscle of two parts. One part is on the left side. One part is on the right side. And the two parts of the muscle meet in the midline, where they are joined by an aponeurotic tendon. And one of the terms that we use for aponeurotic tendons, especially if they're just near, is we call them a raphe. So the left and right superior, middle, and inferior constrictors are joined by the pharyngeal raphe. A tendon, a string or cord of a tendon, that extends in its attachment on itself all the way down to the last part of the inferior constrictor. And the integration of the pharyngeal constrictors is the vagus nerve, pharyngeal nerve 10, which is a motor to the pharyngeal constrictor. The pharyngeal nerve 10, the vagus, is one that you're going to encounter over and over and over and over again in three, if not all, four modules this semester. Because the vagus nerve subserves a lot of different functions. Curiously, it doesn't actually innervate a lot of somatic muscle. Some of the somatic muscle that it innervates includes the pharyngeal constrictors. Generally, the vagus nerve innervates internal organs, and it's sensory, and it's parasympathetic. And this is the case for some of the fibers of the vagus nerve innervate voluntary muscle in the case of the pharyngeal constrictors. The pharynx, for reasons we will see in a minute, doesn't just need to constrict. The pharynx also needs to be able to be elevated and to descend. Specifically, elevated movements of the pharynx are necessary in order for swallowing to occur. Swallowing is under-appreciated by most medical students, unfortunately. It is greatly appreciated by speech and language therapists, who spend at least a year of their training time working around issues concerning swallowing. Which is why there are speech and language therapists. It's because you guys can't be artists for learning if you don't swallow. So if you don't care about swallowing, thank you. But it's a very important thing for reasons we'll see in a moment. So swallowing involves elevation of parts of the pharynx. And there are three pharyngeal muscles, which are referred to as the longitudinal pharyngeal muscles, which, when they contract, elevate the pharynx. So they pull the inferior constrictor, or the middle constrictor, upwards towards the base of the skull. We'll see what the consequences of that are in a minute. And these muscles are called stylopharyngeus. Stylopharyngeus begins on the stylo, the process of the skull, that inserts into the pharyngeal constrictors. And salpingopharyngeus. Salpain is an old Greek word meaning chew. And in this context, salpingo is referring to the pharyngeal tympanic tube, or eustachian tube. So salpingopharyngeus is a muscle that extends from the eustachian tube onto the pharynx. And curiously, as we'll maybe mention in a minute, if you consider the salpingopharyngeus attached to the salblings, the eustachian tube on one end, and the pharynx on the other end, if the eustachian tube is fixed, and the muscle contracts, it elevates the pharynx. But if the pharynx is fixed, and the muscle contracts, it pulls down on the salpingo, on the salblings, on the eustachian tube, which acts to open the eustachian tube. It helps us persist in the opening of the eustachian tube. And then there's palatopharyngeus. And palatopharyngeus elevates and shortens the pharynx. It extends from the soft palate onto the middle and inferior constrictor. And one of the side effects, if you like, of palatopharyngeus, is that there are attachments between the voice box, the larynx, and the constrictors of the pharynx, such that when the constrictors of the pharynx move up in the throat, or when the throat shortens, that larynx is pulled up and down. And one particular important role of palatopharyngeus is in elevation of the larynx during swallowing. You will not see these muscles in the lab, but you do need to know the names and the actions of these muscles in the context of the pharynx. There's a variety of different openings into and out of the pharynx. We need to know the names of the openings and what passes through them. So the first opening that we need to know about are the posterior openings of the nose. Here's the superior turbinate. Here's the middle turbinate. Here's the inferior turbinate, inferior meatus, inner meatus, superior meatus, sphenoethmoid recess. All of these areas converge here at the back of the nose, in this region right here. And on each side of the nose, there's an opening called the nasal colona that opens the nasal cavity into the nasopharynx. So you have two nasal colonae open from the nasal cavity to the nasopharynx. So those are two pharyngeal openings, and those communicate with the exterior because air comes in from the exterior. The next two openings in the pharynx are the gestation tubes, which I'm going to call the pharyngeal tympanic tubes. This is one of them here. This is the sagittal section. The pharyngeal tympanic tubes extend from the pharynx back to the middle ear cavity. I'll say something about all of this later. The next one has an odd kind of a name. It's called the isthmus of the pharynx. So the isthmus of the pharynx is actually the opening of the oral cavity into the pharynx. Above, the upper limit of it, is the soft palate. The lower limit of it is the hard posterior third of the tongue and the upper border of the epiglottis. It's the shape that you can see when you ask someone to open their mouth. Open your mouth and go, ahhhh. Okay, turn the person to your right hand side. The person on the left, open your mouth and go, ahhhh. I see it. What am I looking for? There's like a thing at the back. Like the hole at the back, or what? Oh, like the little dangly thing. Is that it? Is that it? What am I looking for? It looks good. Ahhh. Do you see it? Yeah. That's the uvula. Ahhh. I see it. It's that hole. It opens behind the uvula. It's going down. Yeah. The next opening is an opening in the pharynx that opens to the internal environment, not the external environment. And that is called the laryngeal adipose. And it's this circumscribed space here, partly by the epiglottis, partly by the lateral wall of the larynx. So this space here, coming in here, and the laryngeal adipose is where air passes from the pharynx into the larynx. And it's now in the respiratory system part, pharynx to larynx at the laryngeal adipose. And that's where air goes. And only air is supposed to go in there. And we'll see that there's some special mechanisms to try and ensure that that's the case. The next and final opening in the pharynx is the opening from the most inferior part of the pharynx into its continuation, which is the esophagus, the gut. And here's the esophageal opening here. And the most part of the pharynx here is the esophageal opening. And the esophageal opening isn't open. It's closed. And the only stuff that's supposed to go down your esophagus is your liquid or a semi-solid soup. You're not supposed to have air going down your esophagus. If you do that, your stomach will bloat, and you'll burp. So swallowing air is not a particularly good way to do it. And now we're getting close to looking at what some of the functional aspects of the pharynx are. Because somehow or other, if we have air coming into the nose, and we have liquid in the nose, water coming into the mouth, remember, no matter how liquid you should be, most of the time you should be producing saliva. Okay? So you put liquid in there. And I just said to you, you don't want anything but air when you're in the pharynx, and you don't want anything but liquid or solid coming into the esophagus. So how do we regulate? How does one regulate what goes where? The answer to that is that's what the pharynx is built for. It segregates air, liquid, and solid, and ensures that air goes into the respiratory system, and liquid and solid goes into the digestive system, assuming that it's actually working properly. This is what the pharynx looks like. Remember, it's like a sock. It's hanging down from the base of the skull. So I have come around behind you, and I have chipped off the back of your skull, and I've exposed your pharynx hanging down like a sock. I've taken the scissors, and I've cut the pharyngeal vertebrae up posteriorly, and I've lifted up your pharynx like a book. So I'm looking in your pharynx, and I'm looking from behind. And what can I see when I look in from behind? Here's a nasal covenant here. Okay. Here's a nasal covenant here, and here's a nasal covenant here. Here I can see a middle turbinate, and then an inferior turbinate, and a middle turbinate, and an inferior turbinate. So this is the two openings at the posterior part of the nasal cavity of your pharynx. The eustachian tubes are hidden up here, and up here we can't see them. Here's the isthmus of the fosseas, where you look into somebody's mouth to see their throat. Here's the center part of the uvula of the soft palate. Here's the adductus of the larynx. That's the opening of the larynx where air is supposed to go. With this part of it here, the obstruction you can see, called the pharynoplasty. And here we're descending in the pharynx. Descending, descending, descending. And here's the junction between the esophagus here and the pharynx here. So this is where a bonus of two openings are hidden in the pharynx. Descriptively, we call the pharynx, the parts of it, different names depending on which openings are associated with them. So broadly, everything in the pharynx that's above the level of the soft palate is called the nasopharynx. Everything in the pharynx that is between the level of the soft palate and the ectoplasm is referred to as the oral pharynx, and that's where the isthmus of the fosseas forms. And then everything below the level of the ectoplasm is referred to officially as the laryngopharynx. But there's another term that gets used for this region, which is hypopharynx. And that's actually used clinically quite a bit of the time. So the laryngopharynx, strictly, is the part of the pharynx into which the laryngeal abdomen opens. And the hypopharynx, strictly, is that part of the pharynx below the level of the laryngeal abdomen. And the reason to make note of that is that as the pharynx narrows to come down to the esophagus, so as it narrows, the lowest part of the esophagus, of the pharynx, called the hypopharynx, is a point where stuff can become lodged if you have a failure to swallow or something is too big. So it's a place where stuff gets stuck and you might be choking on it. Unfortunately, that's one of the places where if you're hungry or something, it's a All the places where if stuff gets stuck, if you're hungry, you're known for doing the same. There is an alternative, which I'll tell you about in a future lecture. It's one of the medical students' favorite things to know because it gives you an excuse to carry a knife around with you. And then you can live and hope that some people start choking over a mobile and something. So you can do a little bit of surgical emergency thing and impress everybody with your skills assuming that the person lives. And here's a picture, I think this is from one of the specimens up at the lab, just to show you the nasal pharynx. So just very briefly, here's the superior concha, middle concha, inferior concha, or germinate, superior germinate, middle germinate, inferior germinate, inferior meatus, middle meatus, superior meatus, sphenoid, recessed. Here's the posterior colon, marked in green like here. So air passes under and on, under and on, under and on, and then converges at the back of each nostril or each lateralized nasal cavity and passes into this region here. This is the nasal pharynx. And the structures which are present in the nasal pharynx are the openings of the eustachian tube. Here's the eustachian tube or pharyn-go-tympanic tube here. In the wall of the pharyn- go-tympanic tube, there is a mass of tonsillar tissue, immune system tissue, and these are referred to, there's one on the left side, one on the right side, these are referred to as the tubal tonsils. In the posterior and superior wall of the nasal pharynx, so at the back of it, approximately the midline extending to both sides, and arching up to the root of the nasal pharynx, is another mass of tonsillar tissue, here marked with nine. That mass, midline mass of tonsillar tissue, is called the nasopharyngeal tonsil, or NP tonsil, which is commonly called the adenoid. Sometimes people will tell you they have their adenoids thoroughly removed, which is not because you only have one adenoid. The adenoid is the nasopharyngeal tonsil. So we have two tubal tonsils, one nasopharyngeal tonsil. And air passing through the nasopharynx passes over the tubal tonsils and over the nasopharyngeal tonsil, and then we reach this structure here, which is the soft palate. It's the part at the back of your mouth that's soft. It's unpleasant to touch, so don't do it, but you can definitely feel your hard palate. That's the foamy structure you feel in the roof of your mouth. And then that comes back to the soft palate. And the soft palate marks the boundary between the nasopharynx above and the oral pharynx below. And the soft palate is soft because the soft palate can be elevated, or it can be allowed to drop down. Now when the soft palate is elevated, what we've got here, it touches the posterior wall of the pharynx, and it closes the continuity between the nasopharynx and the oral pharynx, preventing air from passing from the nasopharynx into the oral pharynx, which is what happens when you have your mouth swallowed. So the partitioning of air from liquid and solid, in part, involves the movement of the soft palate upwards and backwards against the rest of the pharynx to close the continuity to the opening of the nasopharynx and the oral pharynx below. Some of you may have had COVID tests. And when you have COVID tests, the target in COVID tests is the nasopharyngeal tonsil. That's why it's so important that you have done. Here's a picture of where the swab is supposed to go when you get a swab on your nasopharyngeal tonsil. It's a long distance back there to get to the back of the throat. It's a long distance. And the image doesn't show how far it's gone. But you can see in the picture on this side, the adenoid is just, this is looking, using a fiber optic endoscope, looking up somebody's nose. And you can see the adenoid at the back. And then to both sides, you can see the opening of the adenoid. This file is longer than 30 minutes. Go Unlimited at TurboScribe.ai to transcribe files up to 10 hours long.