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Hi, everyone and welcome to doctors talk on air pain. Um, today I am joined by, um, would you like to introduce yourself? Hi. Uh, good afternoon everybody. My name is I'm 1/4 year medical student from Saint George's and today um yeah, no, will be going through a pain um to make the session as engaging as possible just as normal. We have these polls which you can answer throughout the presentation and we'll give you guys a feedback form at the end, uh which if you complete, you'll get your certificate of attendance and exclusive discount codes to teach me surgery and pass the MRC S. I'll talk about this a bit more later, but we've also got an exclusive question bank and other resources available on our learning portal. So be sure to check out our website and follow our social media to access them. And finally, before we begin, we'd like to thank our partners, Royal College of Surgeons, Ki Medics MDU. More than skin deep med will teach me surgery and pass the MRC S and without further ado I'll hand over to Luckman. Ok. Amazing. Er, thank you very much for that Bianca Er, so, yes, so like she said, we'll be talking about ear pain. Uh I'll just go over to the learning objectives. Er, so I've kind of um broken down this presentation into a few broad topics. So firstly, you will look at the anatomy of the ear, the outer middle and inner ear and also the salivary glands. We'll also look at the uh the muscles of mastication and facial expression, looking at the innervation, we'll focus on some of the main nerves that we need to know about, such as the trigeminal nerve and facial nerve. And lastly, we'll be looking at the common air pathologies that we are likely to experience in clinical practice and how you can manage those looking both medically and surgically throughout this talk. I kind of just want you to gain an understanding that many of these structures are interconnected and relate to each other and er through various different parts such as er, yeah, neurological and also physical er connections. And so just kind of tune your brain into the fact that there are many connections that we're unaware about. Um and if you're able to do that, then you, you should do really well. So firstly, we'll just look at the anatomy of the external air. So we divide the external air into two parts. So we have the auricle, also known as the pinea and the external acoustic meatus. So the oracle is a pair structure. Uh that's the bit that we can see on the side of everybody's heads. Um It functions to capture and direct sound towards the external acoustic meatus. It's mostly cartilage in a structure. Uh The only exception to that being the lobule, which is the red part at the bottom. Um That's the only part not supported by cartilage. Um The cartilaginous part of the oracle forms an outer curvature which you can see there. That's the helix. Um And there's an innermost curvature as well, uh which is in parallel with the uh with the helix called the antihelix. Um The, the antihelix then uh divides into two separate portions as well. Uh We call these cura. So we have our inferior anterior crus and also the superior posterior crus um carrying on more medially, we have a hollow depression that we call the concha. Uh This is continuous with the external acu uh acoustic meatus. Um And that just, you know, uh directs sound uh into uh the meatus and then immediately anterior to the beginning of the uh uh the meatus is an elevation of cartilage uh which we call the truss and opposite to that is our antitragus. Amazing. Uh So we'll go to the er external acu acoustic meatus now, uh also known as the external auditory canal uh or the air canal. Um and it's an s shaped tube which is situated within the tympanic portion of the temporal bone. Its entrance lies just in front of the mastoid process of the temporal bone. And in adults, it's usually around 2 to 3 centimeters long. So it's not, it's not too long. Um And the endpoint of this is the tympanic membrane also known as the airdrop. So it's quite a thin uh funnel like uh tube. Um and its primary function is to uh channel sound waves into the tympanic membrane. Uh but it also serves as a protective function as well, but we'll go into that a bit later. Uh So the lateral third of the external acoustic matus consists of cartilage and it's covered with skin which extends from the AIC. While the medial two thirds forms is formed by a bony tunnel um which is covered with a thin layer of skin, continuous with the external surface of the eardrum. Um It has quite a narrow opening uh which prevents large objects uh from entering the canal and damaging uh the tym the tympanic membrane. Um within the canal itself. There's subcutaneous tissue uh within specifically the cartilaginous part. So the lateral third, um and it has modified sweat glands, uh known as ceruminous glands which produce ear wax also called er cerumen. Ok. Uh So cerumen along with the small hair cells, uh lines the canal and that prevents um you know, small objects, small particles, uh things like insects um from entering into the eardrum and causing damage. Ok. Additionally, it also moisturizes the canal uh and the eardrum and it contains a, a, an enzyme called lysozyme. Um and this is capable of breaking down the cell walls uh of bacteria. So, any lyme bacteria that should hopefully be destroyed by that lysozyme uh going more immediately. Now, uh we're now in our middle air. Uh So the middle ear is a air f chamber within the temporal bone known as the tympanic cavity. And it's located between the external and internal parts of the ear. Um and it's usually divided into two parts. Uh So we have our tympanic cavity uh which contains our ossicles. So the maus incus and stapes. So those are just really tiny bones uh that vibrate along with the tympanic membrane and transfer that sound into a cochlear. Uh And then we also have our epi tympanic recess and in terms of its boundaries, uh it's bounded laterally by the tympanic membrane er immediately by the lateral wall of the internal air. The roof is formed by a thin by a thin plate of bone uh called the tegmen tympani. And the floor is also very thin uh that uh or, or what sits underneath that is the internal jugular vein. Um what's important with the tympanic cavity is that it's connected to various neighboring anatomical structuring spaces, right. Er So we have two main things. So we have anterior immediately, we have our eustachian tube, er also known as the auditory tube. Er This facilitates equalization of pressure within the tympanic cavity and also the ambient pressure. So the air pressure around us posteriorly um in the epi epi tympanic uh recess, uh we have what we call mastoid air cells. Uh So these are cells um within uh within the tympanic recess. And they, they are a bony structure that have air filled spaces in between them. Um They act as what we call a buffer system, right? So the main uh way of equalization of pressure is the Eustachian tube. Um But these cells, let's say the Eustachian tube isn't functioning as we'd want it to. Um And the pressure in the middle air becomes really low. Um These cells can release air, equalizing that pressure again. OK. Um The eustachian tube again, like we uh like I mentioned is a means of equalizing the pressure between the ambient pressure and the middle ear. Um So it's a cartilaginous and bony tube and it can uh connects to the nasopharynx. Um it extends from the anterior wall of the middle ear uh in an anterior media, inferior direction. OK. Um Opening onto the lateral wall of the nasopharynx. Um So, because it connects two structures, there's always a risk of uh you know, a pathway to share infection. Um So what we can, what we can see is sometimes we can get an infection of the middle ear, uh otitis media. Um what's usually preceded with this is a AU RT, an upper respiratory tract infection. Um So, yeah, we'll get onto that a bit later, but that's uh some clinical context there for you. Uh The tube is very short. Uh So in it's very short, but particularly short in uh Children and it's quite straight as well. Uh So therefore, if they have uh an upper respiratory tract infection, they are more likely um to get middle ear infections. Um And just a couple of other key bits of anatomy, there are some muscles that I want you to be aware of. The muscles are there to provide a, a protective function in the middle e uh let's say there's a really loud bang, right? That produces a lot of sound waves and that can go through the air, causing a lot of vibration and uh causing a lot of damage. So we have something in both called an acoustic reflex. Essentially. What happens is when we perceive a really loud sound is