Body Anatomy Liver

hello everyone! this is joao from kenhub,and welcome to another tutorial. this time, i'm going to be talking about the membranes,the ligaments, and also the muscles of the larynx.you probably, by now, are thinking that what am i doing. i'm combining three huge topicsinto one tutorial, but i wanted to give you a general overview of all of the structurescombined into one tutorial so you can have a good overview of the structure of your bodythat you see now on the screen—your larynx. now, what i'm going to be doing here on thistutorial are these topics. i'm going to go through them. and the first one is a logicalone. i want to define the larynx, clarify what is the larynx. now, followed by that,i'm going to cover the cartilages, which are

structures that you find within the larynx,then followed by the membranes and ligaments, and then i'm going to finalize this tutorialwith the muscles of the larynx. so let's start here with the very first topicon our list, the larynx. what is the larynx? let's define this structure. this structureis usually a subject of confusion, and we need to clarify it right now on this tutorialbefore we go and talk about every structure that you find within the larynx.now, this is an intricate anatomical complex that you find, as you can see here on thisimage, within your neck. and we're looking at the anterior view of the neck, and youcan clearly see here the larynx. and it is comprised of different soft and hard tissues.as you've seen on the list that we talked

about in the beginning, it's comprised ofmuscles all the way to cartilages. we're going to be covering them here on this tutorial.now, it's important to mention that this structure allows us, human beings, to articulate sound.without it, i couldn't be doing this tutorial right now. and also, this is going to be theinlet that's going to have air coming through and go all the way to your lungs and alsoout of your lungs. so this is an inlet where air passes through, and we're going to see,more or less, a bit more details of where it's going to go through.now, also important to mention is that, if you want to give exact coordinates of whereto find the larynx in your body, you can say that it's found in the midline of the humanbody at the level of the third to the sixth

cervical vertebrae. and also another importantthing for your notes is that the larynx connects the pharynx to the trachea.before we move any further, i want to make a clarification between two structures thatwe already talked about briefly: the larynx, which is the subject of this tutorial, andalso the pharynx, which has a very similar name and sometimes can be subject of confusion.believe it or not, it has been for me. it was a subject of confusion, and i definitelyhave to clarify this for myself, and now, for you guys.now, what you're looking at right now is an image of the dorsal view or the posteriorview of your neck, of the pharynx. if we were to cut it open, we cut the muscles of thepharynx, as you can see here, and open them

or open the pharynx as a book, like a bookas you can see here, exposing the structures, clearly seeing the connection between them,and this is how we're going to make the distinction between these two structures.now, as you can see here, there is, here, the nasal cavity or part of the nasal cavityand also the oral cavity. you'll notice here the root of the tongue. now, keep in mindthat the pharynx is going to be an entrance hallway. imagine that we're talking abouta house. the nasal and oral cavities will serve as a door where food and air is goingto come through, and then there is an entrance hallway called the pharynx where they're goingto, then, be or split in two different places in your body, into two different corridorslet's say.

one is going to be this one right here, thestructure that we're going to talk about on this tutorial, the larynx, where air is goingto go through. and then the other one is going to be this one right here, the esophagus,where food is going to go to. and as you know, the esophagus is then connected to your stomach.if we were to remove the esophagus and the thyroid gland, you can clearly see that thelarynx, this inlet that we're going to talk about, is connected to the trachea, and asyou know, the trachea is, then, connected to the lungs, so you can clearly see thatthis, or the larynx serves as the inlet for air to come through. so now, the distinctionis done between pharynx and larynx, we are definitely ready to move on and talk aboutthe larynx in a lot more detail.

now, let's move on to the second topic onour list, the cartilages of the larynx. now, what you need to know is that there are ninetotal, nine individual cartilages. so three of them are paired, and three are not. andif we count them all, then there're nine in total. and the first group of them that we'regoing to talk about are known as the hyaline cartilages.now, the first one on the list of the hyaline cartilages is this one here that is the largestof all laryngeal cartilages and is known as the thyroid cartilage. now, the thyroid cartilageis comprised of two laminae. we can see here on the image on the right side—two laminaeand one lamina here that will, then, fuse on the lower third as you can see here. sothey will fuse these two laminae. and keep

in mind, yes, lamina is singular; laminaeis plural. now, on the superior portion of these two laminae, you see that they're notfusing which allows the formation of what is known to be the laryngeal notch.now, the thyroid cartilage is somewhat famous because it defines one of your, the landmarksin your body. if you look at your neck, especially the neck of men, you'll notice the adam'sapple. now, the thyroid cartilage is what defines this landmark, specifically this prominencehere that is known as the laryngeal prominence, and this is what defines the adam's apple.so if you want to be a little bit more technical next time you talk to your friends, just say,"look at my laryngeal prominence." i would say this wouldn't be a common practice, butokay, you can use a more technical term from

now on.now, what i'm going to do now is to move on to also the posterior view of the thyroidcartilage using that image that i talked about to distinguish larynx versus pharynx, andyou can still see here the thyroid cartilage in green because i want to show you this membranehere. this is known as the thyrohyoid membrane, which we will briefly mention later on aswell. but you can also see here in this image. ifi were to close one of the portions of the muscular layer of the pharynx and strip theother one completely, you can see more structures exposed, including the thyroid cartilage,which you see that the thyrohyoid membrane is connecting the superior part of the thyroidcartilage with the hyoid bone. you see a portion

of the hyoid bone right here. so this thyrohyoidmembrane is connecting these two structures. so let's move on to the next one, the secondcartilage on our list, hyaline cartilage, also known as the cricoid cartilage. now,the cricoid cartilage is shaped as a cygnet ring, and you can notice here that the cygnet-shapedlamina faces posteriorly. another important thing to know about the cricoid cartilage,and you can notice here on this image, is that it's a complete ring of cartilage—sono interruptions like we've seen on the thyroid cartilage.now, another important thing to also notice here on the cricoid cartilage is on the inferiorportion. it has here a ligament that we need to remember. this is the cricotracheal ligament,which connects the cricoid cartilage to this

structure here, the trachea. now, what youneed to also remember is that the strength of this structure is very important, and alsothe thickness, because it's necessary for holding the upper and lower respiratory tractstogether. it's time for us to move on to the third hyalinecartilage on our list, the arytenoid cartilage. notice that this is a paired cartilage. sothere are two arytenoid cartilages. now, one important thing is that, in terms of articulation,you'll notice that the arytenoid cartilage is articulating inferiorly with cricoid cartilageright about here. now, on its apex right here, it's articulating with these small cartilagesthat we're also going to talk about later on. they are known as the corniculate cartilages.an important thing to also see here is that

it interacts a lot. there are a lot of importantpoints where the muscles will use as attachment points on the arytenoid cartilages. we'regoing to look at that in more detail later on in different tutorials, but you can havehere an illustration showing that. and also, an important note that i need tohighlight here on this tutorial is the fact that the arytenoid cartilages are, from thosethree hyaline cartilages that we looked at, are the only cartilages or only hyaline cartilagesthat are actually paired. the cricoid cartilage and the thyroid cartilage are clearly notpaired. yes, you've seen that the thyroid cartilage has two laminae, but in terms ofthe full thyroid cartilage, it's only one. so the only paired are definitely the arytenoidcartilages.

we are definitely done talking about the hyalinecartilages. it is time for us to move on and talk about the elastic ones, the elastic cartilages,starting off with this one here seen highlighted in green on a lateral view of the cartilagethat defines as the cartilaginous framework, let's say, of the epiglottis. for that reason,we call it the epiglottic cartilage. this is a very important structure that youfind within your neck because, once you swallow food, what's going to happen is food is inthat hallway that we talked about, the pharynx, and this epiglottic cartilage will functionto close the laryngeal inlet. that way, preventing food from going into your lungs, and instead,going into where it's supposed to be, which is the esophagus followed by the stomach.next on our list is also a paired cartilage

known as the corniculate cartilage, and asyou can see here, we talked about it before when we talked about these ones here thathave a pyramidal shape, the arytenoid cartilages, and they're articulating. so the corniculatecartilage is articulating inferiorly with the apex of the arytenoid cartilages—veryimportant. i also have here an image that shows you animportant feature of the corniculate cartilages, also the posterior view of all those structuresthat we talked about in the beginning. we're going to zoom in to show you here the posteriorview of the corniculate cartilages and also the arytenoid cartilages, because it is herethat, on the apex of the arytenoid cartilages where the aryepiglottic fold inserts, andthat is how the nodule shape of the fold is

formed as you can see here. it's thanks tothese structures. this is the aryepiglottic fold.now, moving on to the next cartilage on our list, also a pair, known as the cuneiformcartilages. now, keep in mind that, here, you can see the actual cartilage. it's coveredin this layer here of, let's say, the mucus layer that you cannot see, that it's not allowedus to see, these very small cartilages that are elongated pieces placed on either sideof the aryepiglottic fold. and the cuneiform cartilages do not attach themselves to anyother cartilages, just the muscles and ligaments. i have mentioned it before, but i wanted todo a quick reminder, a quick note, so you can add to your own notes, is that, of thosethree elastic cartilages, only two are paired:

the corniculate as you see here on the leftside, and on the right side, the cuneiform cartilages. only these two cartilages arepaired. at this stage, we have covered all the cartilages,all the laryngeal cartilages, but i still want to mention a few points, clarify a fewpoints here about the thyroid cartilage. notice, now, that we're looking at it on the interview,and you can clearly now see the thyrohyoid membrane right about here. it is connectingthe superior portion of the thyroid cartilage with this bone right here, the hyoid bone.now, what i also want to mention about the thyroid cartilage is that it contains a fewstructures, a few projections that are paired, and they are important to mention also andto highlight on this tutorial. now, these

are known as horns. we couldn't find a bettername. horns, they're superior and inferior horns of the thyroid cartilage. and theiractual projections from the inferior border—sorry—the posterior border of the thyroid cartilageas you can see here. and they have these projections that we call horns.and of course, if we're talking about a superior projection or a projection that goes superiorly,we're talking then about a superior horn or two superior horns. and then also, you have,alternatively, the inferior projection that is known as the inferior horns of the thyroidcartilage. moving past all the cartilages, we're goingto go to the third topic on our main list, the membranes and ligaments of the larynx.now, what we're going to do, i want to cover

nine of the major ligaments and membranesthat we need to—i think they are the most important ones to remember. and an importantdistinction here is that there are extrinsic and also intrinsic membranes and ligamentsthat you find within the larynx. we're going to start off with the extrinsic,and first on our list is the one that we've been talking about throughout this tutorial,especially when we talk about the thyroid cartilage, the thyrohyoid membrane, whichis the membrane that is definitely stretching between the superior border of the thyroidcartilage all the way to the hyoid bone. and you can also see here a new view, a completeview of our posterior view of the thyrohyoid membrane.now, moving onto the next one. this is a small

one. let's say a small ligament or two ligamentsthat you find on the posterior side of the thyrohyoid membrane. they are known as thelateral thyrohyoid ligaments. and these are thickened portions of the thyrohyoid membrane,like i mentioned, that which pass through the superior horn of the thyroid cartilage,as you can see here, and then connects all the way to the posterior end of the greaterhorn of the hyoid bone as you can see. moving on to the next ligament on our list,this one seen here anteriorly now known as the median thyrohyoid ligament. now, thisis a thickened band of fibers of the thyrohyoid membrane which, if i zoom in a bit, you cansee that it's connecting here to the superior thyroid notch or the laryngeal notch all theway with the body of the hyoid bone right

about here.the next one, next ligament, is this one seen here a bit more inferiorly. this is knownas the median cricothyroid ligament, and this is a band that is a part of the conus elasticus,as you can see here, and connects anteriorly with the inferior border of the thyroid cartilage,as you can see here, all the way with this arch of the cricoid cartilage, right abouthere. you can also see another image laterally where we can show the inferior portion ofthe thyroid cartilage which this ligament's connecting all the way with the arch of thecricoid cartilage. the next one on our list is the cricotrachealligament, which i also talked about previously, which connects caudally the cricoid cartilage,as you can see here. so inferiorly, it's connecting

the cricoid cartilage with this ring here,the first cartilage from the trachea—so the first tracheal cartilage. you can alsosee it here laterally, the cricotracheal ligament. we have covered all the extrinsic membranesand ligaments of the larynx. it is time for us to talk about those we find on the inside,the intrinsic membranes and ligaments of this structure. and the first one that we're goingto talk about is this one seen here, highlighted in green, known as the elastic cone. also,we can call it conus elasticus. so you can use these two terms interchangeably.now, this is a thicker inferior portion of fibroelastic membrane of the larynx, and itarises from the inner surface of this cartilage that we talked about. if you remember well,yes, this is the cricoid cartilage, and this

elastic cone is continuous with the vocalfolds, as you can see here. now, moving on to the next one, this is avery important ligament, especially if i want to be talking with you right now. this isthe vocal ligament, which is enclosed within the vocal folds. they are enclosed becausethis is a pair of two ligaments. and each ligament consists of a band of elastic tissueor yellow elastic tissue attached in front of the angle of the thyroid cartilage, asyou can see right about here all the way to these pyramid-shaped cartilages. if you rememberwell, yes, these are the arytenoid cartilages, and you'll notice here that the vocal ligamentis just attaching behind the vocal process of the arytenoid cartilage.the next one on our list is actually a membrane

known as the quadrangular membrane, and asthe name indicates, this is a square-shaped membrane—relatively large when comparedto the other structures that we talked about. this is a layer of submucosa. it containsthe cuneiform cartilages, as you can see here, and it extend from here, the lateral aspectof the epiglottis, all the way to the arytenoid cartilages, as you can see here.now, the superior border is in the aryepiglottic folds. so as you can see here, this is clearlya definition of what actually defines that aryepiglottic folds. and the free inferiorborder of the quadrangular membrane, as you can see here, is this ligament—the nextligament, the final ligament that we're going to look at—and this is known as the vestibularligament, which is the vestibular fold when

covered by mucosa.it is time for us to move on to the last topic on our list, the muscles of the larynx. withoutfurther ado, let's list the seven muscles that we're going to be talking about. thefirst one, the cricothyroid, followed by the thyroarytenoid, then the posterior, and thelateral cricoarytenoids. the transverse and oblique arytenoids, and then finally, thevocalis. let's start off with the very first one onour list seen here, highlighted in green, this is the cricothyroid muscle. now, lookthat... notice here that the origin point is going to be the arch of this structurehere that we talked about, the arch of the cricoid cartilage, and then it's going toinsert on the lamina of the inferior horn

of the thyroid cartilage. now, this structureis important because it increases the tension on the vocal ligaments.another important thing that i need to add, other than just these muscles, for more context,i need to add that this is the only laryngeal muscle that is supplied by the external laryngealnerve. whereas, all the others are supplied by the recurrent laryngeal nerve.now, let's move on to the next one on our list, this muscle also seen here, highlightedin green. it is known as the thyroarytenoid muscle. this muscle actually decreases thetension of the vocal ligaments because it originates right on the angle of the thyroid,as you can see here. then, it stretches all the way to the arytenoid cartilage.now, another muscle that i want to talk about

before i include all the muscles, so you cansee the thyroarytenoid muscle in context, we're going to, now, move on to the next one.and this one is an eighth muscle. it's not included in the list that i talked about ofthe seven muscles, but i wanted to include, because sometimes, this is considered as aseparate muscle. and it is known as the thyroepiglottic muscle.and it is a considerable number of fibers of the thyroarytenoid muscle that are prolongedinto the aryepiglottic fold. so as you can see here, now, i'm adding the thyroarytenoidmuscle so you can see the prolonged fibers that, then, are then considered as a separatemuscle, the thyroepiglottic muscle. the next muscle on our list is going to bethis one seen here, also highlighted in green.

this is known as the posterior cricoarytenoidmuscle. now, as you notice, this is muscle is originating from the posterior lamina ofor the posterior portion of the lamina of the cricoid cartilage, and it goes to inserton the muscular process of the arytenoid cartilage. now, an important point that i need to addhere about the posterior cricoarytenoid muscle is that this muscle is responsible for openingan important structure within the larynx known as rima glottidis. now, this is a space thatyou... a space actually or an opening that you find between the vocal chords and alsothe arytenoid cartilages. now, there are other muscles that are goingto contribute for the closing of this structure, the rima glottidis, and these are going tobe the lateral cricoarytenoid, the transverse

arytenoid, and also the oblique arytenoidmuscle. so write it down that these muscles, this list will actually do the opposite functionof the posterior cricoarytenoid muscle. next muscle on our list is this one that yousee on the screen right now. this is known as the lateral cricoarytenoid muscle. now,as you notice, it's originating from the lateral portion of the arch of the cricoid cartilage,and that inserts right next to the posterior cricoarytenoid muscle on the arytenoid cartilage,as you can also see here on this image. now, moving on, we can talk about the nextmuscle on our list. this is known as the transverse arytenoid muscle. now, this muscle is originatingfrom the muscular process of the arytenoid cartilage and fastens itself to the muscularprocess of the opposing arytenoid cartilage.

the next muscle is going to be this one seenhere in a very similar location to the previous one, and this is known as the oblique arytenoidmuscle. now, the oblique arytenoid muscle has an interesting origin insertion, and asyou can see, it's originating from the muscular process of this arytenoid cartilage, and thenit's supposed to go and insert on the opposite side on a different arytenoid cartilage, specificallyon the apex, as you see the other portion that should be coming from the other side,and it's now inserting here on the apex of this arytenoid cartilage. also, notice hereon this image that the oblique arytenoid muscle lies on the surface of the transverse arytenoidmuscle. now, we're going to be talking about the lastmuscle on our list—this one that you see

on your screen. this is known as the vocalis,and this muscle is originating from the posterior surface of the thyroid cartilage as you cansee here and goes all the way to insert on the vocal process of the arytenoid cartilage.now that you'd just completed this video tutorial, then it's time for you to continue your learningexperience by testing and also applying your knowledge. there are three ways you can doso here at kenhub. the first one is by clicking on our "start training" button, the secondone is by browsing through our related articles library, and the third one is by checkingout our atlas. now, good luck everyone, and i will see younext time. https://www.kenhub.com