Full transcript
0:00Greetings once again my neuroanatomical scholars, today I bring you the second
0:04installment of the ear, we will talk specifically then about the anatomy of the middle ear,
0:09in previous videos we talked about the external ear and in the subsequent video,
0:15which would be the third installment of the ear, we will then address the inner ear and all its structures,
0:21before starting I invite you to subscribe to my channel here in the lower right corner
0:25click where it says subscribe. So the ear is made up of three large
0:31portions, an external ear that we already covered, as I told you in another video, made up of two large
0:37structures that are the pinna and the external auditory canal, then for this
0:44class the middle ear we will talk specifically about the big box. tympanic membrane and then our third
0:49installment, as I already told you, where we will address the inner ear, made up of a set
0:55of structures known as the labyrinth, which in turn is subformed by the cochlea and the
1:02semicircular canals. You already know then that we will talk about the tympanic cavity of the middle ear,
1:08then the tympanic cavity is everything that is found after the tympanic membrane,
1:12in fact this structure that is the tympanic membrane is what separates the external ear
1:17from the middle ear. , then in addition to the tympanic membrane we will talk about the
1:23tympanic cavity itself, which is in itself what we know as the middle ear and we will also talk about
1:30the eustachian tube, auditory tube or also called pharyngotympanic tube, however
1:36this tube was addressed a lot better in the pharynx video, okay? So stay tuned to the video
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2:14then there is a large cavity that is the middle ear that communicates downwards,
2:19it is a cavity that is It communicates downward and anteriorly through this tube
2:24called the pharyngo-tympanic or auditory tube with what is the pharynx, more specifically with the
2:30nasopharynx, and it also communicates posteriorly through this hole that you see here.
2:36What happens is that it shows By cutting the temporal bone, we cannot see that this is a hole,
2:41but this hole is called the mastoid tympanic canal because it is basically communicating
2:46the tympanic cavity, which is this, with the mastoid portion of the temporal bone,
2:52something important is that the middle ear is located clearly in the temporal bone,
2:57then through the mastoid tympanic canal or duct the middle ear will communicate with the
3:05anthromastoid upward and posteriorly as well as with the mastoid cells, then
3:11it communicates downward through the tube here. pharyngotympanic with the pharynx and
3:17posteriorly with the antrum and the mastoid cells through what is the
3:22mastoid tympanic duct, we are then going to give the limits in the tympanic cavity, as it is a box, guys,
3:27you have to imagine a structure of six limits like a die, that is, it will have
3:33a roof, or an anterior limit, a posterior limit, a floor, a medial limit and a lateral limit,
3:40so we are going to describe each of the limits of that tympanic cavity. We are going to start first
3:45with What the tympanic membrane is, what the tympanic membrane is corresponds to what
3:53the external limit is, so we are going to describe the tympanic membrane and then we talk about
3:59the membrane as a limit, so that tympanic membrane is basically a fibrous structure
4:05that is The one that vibrates with the vibrations is worth the sound redundancy that comes through the
4:11external auditory canal, which is this, this membrane I already told you that separates my external ear,
4:16middle ear or tympanic cavity, it is attached to what is the tympanic lamella of the
4:24temporal bone that we are going to see now and it will be made up of an external face that is the one
4:30that faces the external auditory canal, which is covered with the epithelium of the
4:34external auditory canal, which is basically skin, it is epidermis, while it will have a inner surface that
4:41is covered by the mucosa of the middle ear, which I have not told you about but is a simple cubic epithelium,
4:47Between both sides, the external one, which is epidermal, and the internal one, which is the mucosa of the middle ear,
4:53there is a fibrous lamella and that is also the fibrous lamella in which
4:58it is inserted into everything that is the tympanic lamina of the temporal bone as we see here in This cut,
5:05this entire groove that you see there is part of the tympanic lamella, what you are seeing
5:10here is the external auditory canal, its bony portion and here then on these edges where
5:16that tympanic membrane is being inserted in this view, it is an external view In a view of the
5:23external auditory canal, this is what we find when we do an otoscopy with what is
5:29the device with the otoscope, then we are going to see the components of this tympanic membrane,
5:34on its external face it has a diameter of approximately one centimeter , a more or less rounded shape
5:39although some authors say that it is oval in a longitudinal sense,
5:43specifically its external edges we find the tympanic annulus that this tympanic annulus is
5:50like an annulus fibrosus, they are more fibrous than the rest of the membrane, that is, the part that They are
5:55inserted into the tympanic lamella, now in the center we find an area that is the tip of the handle of
6:03this bone that I love right now on the inner face or tympanic face of the membrane that is the hammer,
6:09it is the tip of the handle of the hammer, also We find in that external membrane the
6:15handle of the hammer itself and what is the lateral process of the hammer, which is this structure that we see
6:20here, then we see the tip of the handle, the magician and the lateral process, from that
6:28lateral process of the hammer we find two folds, one thing I didn't mention, this is posterior and this
6:35is anterior, remember that vision is lateral so this is posterior and this is anterior so
6:40this fold that comes out backwards from that external process of the malleus is the
6:48malleolar fold. posteriorly, whenever we see the malleolar prefix we are not referring to the malleus, in
6:53fact we call it malleolus or hammer, while the fold that comes forward would be the
6:58anterior malleolar fold, posterior malleolar fold and anterior malleolar fold; Now there are two large
7:06portions of the tympanic membrane, this entire portion that is inferior to the folds is what
7:11we call the tense portion. This is all because it is the part of the membrane that is,
7:17let's say, at the edges of the temporal bone and is tense, it is smooth, It is very well inserted,
7:23while the next portion is the flaccid or even flaccid portion, the flaccid portion is the one
7:29found between the posterior folds and the bad fold, the anterior fold is called that
7:34because it is an area that is inserted in my mind. in the temporal bone so that the membrane
7:38is not as tense as it is in the lower portion which is the name right now what we see
7:43here which is in the anterior-inferior quadrant remember that this is anterior and well this
7:49lower front the famous as the use with the new luminous anatomical structure as
7:54such you will not find it anatomically in the membrane only that when the light of the others
7:59copied reflects the membrane when they also stop it is healthy we see that a cone of light is reflected
8:04in that quadrant before The lower part, in fact, it is said that if the cone is not seen it is because the membrane
8:08is inflamed and that patient probably has otitis media, just guiding us with that
8:14luminous cone, this is a vision cutting what is the tympanic membrane, all of this in the annulus fibrosus.
8:20so this would be the tip of the hammer, the navel formed the handle, the hammer
8:27of the lateral apophis and that structure that you see here is a little poorly drawn, but it is an image
8:32of the net itself and this is what you see here in the chorda tympani nerve that I will address later
8:37that it is a branch of the facial nerve. Sometimes the chorda tympani stage is seen from the outside,
8:41that is, from the external portion of the membrane, but sometimes it is not possible to see this
8:48view, now in reverse, we are seeing in the tympanic cavity. outwards here we are looking from
8:52the external auditory canal towards medial removing the tympanic membrane and here now we are seeing
8:58as if we were going inside there and now we saw the other way around that is to say outwards also
9:03the handle of the hammer and here we see it we see the tip there that forms the navel and what is seen towards
9:09that the lateral apophis this nerve that we see here passing between the malleus and the incus that we will see
9:15that it is this bone that is here the chorda tympani nerve now well it turns out guys remember
9:22that we are talking about the external limit the lateral limit of the tympanic cavity so
9:29This external limit in the tympanic cavity will also be made up of a portion that is not the
9:35tympanic membrane itself, but it is above the tympanic membrane. We call that portion the
9:40recess and pitin panic. This recession and pitin panic is part of the temporal bone and there we basically
9:47find what is the head of the malleus, the lateral popis of the malleus as well as the
9:54incus, the head of the incus and the horizontal branch of the incus, many authors divide this
10:00tympanic surface into what you see here red as epi tympanum, whatever comes blue as months- eardrum what
10:06you see here in green like and odd pod then the epp and eardrum yp eardrum or recess e pitin
10:13panic is also considered the anterior limit of the tympanic cavity the anterior no
10:19forgiveness external limit in the tympanic cavity together with the tympanic membrane kilograms better everything
10:26that is recess speaking panic and its content as I told you what is the head of the incus with
10:30its horizontal branch each time hammer with lateral process berman of the malleus towards more inferior
10:37the lateral limit then composed of everything that is the tympanic membrane This is then what
10:43we call external pairs or membrane wall, let's now move on to the roof, remember that the clinic had six
10:51limits, which we also call the mental tec wall, that roof is made up of
10:56a bone lamella called chin tech, and the name is still the measurement or Whether it is the roof,
11:03then what the tympanic cavity is, it separates the middle ear from what the middle cranial fossa is,
11:12the tec mind now, as the lower limit or floor, we are also going to have a portion of the
11:18temporal bone in which it is located. It is a fossa that we call the jugular fossa that jugular fossa houses what
11:27is the gulf, the superior bulb of the internal jugular vein, that is why it receives that name, you know that
11:34then the floor is the jugular wall, formed by the jugular fossa, so far we have
11:39the wall Externally, the ceiling and the floor, we are missing three limits. We will talk first about
11:47the anterior limit so that you understand this image. This is a medial vision, that is, we are seeing
11:53a half lateral grace because we see what the tympanic membrane is, so notice what
11:58anterior anxiety we find. First, all of this that is here would be all of this would be posterior and all of
12:04this that we are seeing there would be lateral. We are looking from medial to lateral. So we are going
12:09to find three structures in that anterior wall that we also call the carotid wall. We
12:15first find a duct or semi-duct through Where this muscle passes, which we will see later, which is the
12:20muscle of the inferior hammer to the semiconductor, the muscle to the hammer, we find what is the
12:27entrance hole to the farin tube with the tympanic, another auditory tube, and in the lower part
12:32we find the groove that kisses the duct. Iraqi carotid wall, which is called the
12:38carotid wall, this anterior wall we see much better in this image. All this would be the
12:44anterior wall. We see here what the semiconductor is. The malleus muscle. We see here the orifice
12:50. The tube made the tympanic membrane and a little more before lower which is more or less at this level
12:55is that we find the carotid duct which we also see much better the semi conductive
13:00the muscle we see the tube made tympanic is more antero-inferior what is the duct
13:07the duct for what is the internal carotid We are going to talk then about this wall, which is
13:13the posterior wall, which we are also going to call the mastoid wall. This posterior wall is going to be
13:20made up of a series of structures. First, this bone structure that we see there, which I am
13:26pointing out is the temporal pyramid, where this originates. muscle that we will see later, which
13:32is the stapes muscle, in addition to this pyramidal eminence towards the back, remember that at the beginning
13:38of the video I told you that there was what was the antrum plus your video and the mastoid cells,
13:44which are these aerated cells that you see here To see it better this would be the pyramidal eminence this
13:51It would be the master antrum and video and these would be the mastoid cells. Remember that the communication
13:56of the tympanic cavity with this antrum and these the day will be through a hole that was
14:01here which was the most toybe tympanic canal or also called alytus ar and your Addicts
14:07without panic are also called by some authors. So these are the structures that we basically
14:12find in what is the posterior face. Let's talk about the last limit that we are missing,
14:19which is the medial wall. It is the labyrinthine wall. This medial wall is important because the ear.
14:26The middle is so small that between the wall, which would be the membranous tympanic membrane, and the medial wall, which is
14:33labyrinthine, which is what connects the middle ear with the inner ear, what there is is 2
14:38to 6 millimeters, that is extremely small, it is a very small cavity. small now this view is a
14:46lateral view that is to say they are moving laterally towards medial we cut the tympanic membrane and this
14:51is what we find then what structures do we find in that middle wall the labyrinthine
14:55first we find the duct of the semi of the eminence sorry of the
15:02external semicircular canal or lateral semicircular canal, which is a canal that we will address when we talk about the
15:08inner ear, then we find the eminence left by the facial nerve duct and how
15:13the facial vein is entering below it, we find the oval window, which is the one that is covered by this
15:19bone What is the stapes bone? That oval window is also known as the vestibular window. Then
15:26we find a bony lamella called the cochlear process. The bony minilla separates the window
15:34from the round window that we find below that cochlear process. In addition to that,
15:41we are going to find a great eminence, which is the so-called tympanic promontory, is not the same
15:47promontory of the sacrum as that of the sacral bone, which is something else to have a tympanic promontory,
15:51and above the tympanic promontory we find this plexus, which is the tympanic plexus, formed
15:57largely by the glossopharyngeal nerve, so the structures that we find here remember
16:02then the lateral semicircular canal the facial nerve canal the foramen or
16:08oval window the cochlear process in the round window and what is the promontory along with what is suplex
16:16or team panic all this in the medial wall like this We find the medial wall, that is, what comes
16:22here prominently would be the promontory, what you see here is the duct in the facial lip, the prominence,
16:28ok, here the facial begins to enter, and what you see here, the lateral semicircular duct, the
16:34prominence, the prominence left by that duct of this window, see that they have an oval shape, this
16:40would be the cochlear process, which is the minilla, that is, Vélez Díaz, which separated the oval window from
16:45this hole that is here, which is the round window, so what we find
16:50in the medial wall a way of summary guys here in this image as I told you the eardrum is
16:55a box that's why we call it tympanic box here we remove what was the tympanic membrane
17:01and we find this structure basically you can see the roof which is the segment imposed
17:07in the anterior part we find the orifice of the tube made the tympanic membrane and what
17:13was the carotid duct, the prominence left by the carotid duct as well as
17:19the memories that we found the semi-duct of the malleus muscle on the floor we found the
17:24jugular fossa, which would be the internal wall well the lateral semicircular canal that comes
17:31here ok what is a little lower would be the facial nerve canal then the foramen ovale
17:39the foramen or round window and this would be the promontory together with the sympathetic plexus
17:46on the posterior wall remember that we find the pyramid and the mastoid tympanic duct, which
17:52was what first communicated with the antrum and with the mastoid cells better than nuanced
17:58that you will not find this on the internet, then we are going to address the ossicles of the middle ear
18:03in the middle ear we are going to find a chain of ossicles, which are the three smallest bones
18:08in the entire body, namely, we find the malleus, which we also call the malleolus, we find the
18:13incus, which we also call in q2, and we find the muscle muscle, not sorry, the stapes bone, which
18:20We also call this request, let's see each one of them, this is a view from medial
18:26towards the tendency, we are seeing the medial face of these bones, this would be anterior, this would be
18:31posterior, this whole face, we see the medial one, and this is great that we see, so We do not see that
18:37it is towards there, it would be the side. We are going to start with the hammer, which is one of the ones that
18:43has the most anatomical objections. We are going to have the handle, which we already studied. The head. Remember that any narrow area
18:48after the head is called the neck, so this would be the head this would be the neck the
18:53handle then we would have the lateral process remember that what the membrane was inserted was
18:59the lateral process and the handle and this tip wants what the navel reported and it is policy that
19:04tele does not know what the process is previous of the hammer now we are going to move on to the anvil or even
19:11sejun that incubated basically what it has is a body that is this entire area that you come
19:16here that articulates with the head of the hammer and from that body comes a horizontal branch also
19:22called branch upper lower branch also called vertical branch now this entire
19:29articular facet is called cilic articular area for what is the malleus this tip which is the one that
19:37articulates with the stapes is what we call the lenticular process of the incus now the stapes
19:45is the bone that is going to be in charge of, let's say, join the rest of the bones to what is the duct, to the
19:55duct, sorry, it tells me what the inner ear is, the stirrup, in fact, it covers what
20:01the window is or what I explained to you. Orito it is going to be made up of a head that created
20:06three bones and they have one head it is going to have two branches this branch let's stay here remember that this
20:10is anterior so this would be the anterior branch and this one that we see here is the posterior branch both
20:15branches support me In what is the base of the stirrup, the base being then what covers me
20:22from what is the oval window. Let's see right now how it is for the oval window, but first I
20:28will explain the articulations between these judges and then we will finish the first articulation.
20:34What is going to occur are two synovial joints, one that occurs between the malleus and the young, which
20:42we are going to call the joint, including the malleolar, it is a reciprocal socket type joint, that is,
20:49it is an axial joint. I can also do four movements. We call
20:54the saddle joint the second joint, which is also a
20:58synovial joint. It is the one that is going to be given between the police and lenticular of the incus and the head of the stapes
21:04. The raw joint is also a synovial joint, but one
21:10joint type in osteoarthritis can make me complete movement, it moves in all three and it
21:16can theoretically make me six movements, that is, this is a very mobile joint, it is more mobile in
21:22fact and on the slightest side lastly, but as you see here We have the joint that will
21:29occur between the stapes and the oval window and that is not a synovial joint like the other
21:35two that we saw, this is a fibrous type joint within the fibrous one, it is a syndesmosis
21:40that is why we call it tympanic syndesmosis It's pedic ok we see well here this would be the inner ear
21:47this would be the vestibule and this would be the vestibular window we see then how the stapes
21:53in each perfectly in the vestibular window do not get confused cover the vestibular window until
21:59the round window comes down it is not covered by what the stapes is the vestibular which
22:05is covered by it now the muscles management gone middle we will first find the tensor
22:11tympani muscle which we also often call the malleus muscle this muscle originates in
22:16the cartilaginous portion of the pharyngo-tympanic tube benach and the tube manufactured tympanic
22:21is in close relationship with the memory that is on the anterior surface of the tympanic cavity and is inserted
22:27into the handle of the malleus here as it is being inserted into what is the handle of the malleus is
22:34enervated by a branch of the lower maxillary nerve, which you already know is a branch of the trigeminal nerve
22:39and its function, then in the same name it tells you to tighten the tympanic membrane, they are muscles
22:46important for hearing then we are going to see the stapes muscle this muscle the stapes
22:51this tiny muscle that is here we also call it muscle is pei of this muscle
22:56originates in everything that is the pyramidal eminence of the temporal bone that is named when they are
23:01talk about for the posterior of the tympanic membrane of the tympanic cavity, sorry, it
23:06originates there in this pyramidal eminence to be inserted into what is the head and neck of the
23:12stapes here the pyramidal eminence that shows me what is the origin then of this muscle of the
23:20stapes, see here how it is being inserted into the neck and into the head of what that stapes bone is,
23:27it will then be enervated by a branch of the facial nerve, unlike that of the
23:32malleus, which I told you was enervated by what was the maxillary nerve. Inferiorly, its function
23:39is then said to be to rotate the stapes and take it outwards, that is, towards the side.
23:45Now, as this tympanic membrane is enervated, it is a restrictive innovation. It is said that the
23:52external face is firstly by the trigeminal and by the vagus while that the internal face is first, it goes
23:58through the glossopharyngeus, which innervates the entire mucosa of the pharyngo-tympanic tube and what the
24:05middle ear is, how is that middle ear going to be sensitively inervated, but dear, we are talking about the
24:13innervation of the tympanic membrane, let's To talk about the middle ear, this nerve is going to be in the steam,
24:18which is a branch of the lower maxillary nerve, which is the temporal auriculotherapy nerve, as you see
24:23here. In addition, I take this opportunity to teach this tool, which is the motor branch that goes to
24:27the tensor muscle of the eardrum then through the temporal atrial nerve that makes up a
24:32large part of what is the middle ear. In addition, it will have a branch of the ninth for walking,
24:38which is the sympathetic nerve, and an auricular branch of the tenth pair so that it is denied. both
24:43by the trigeminal and the glossopharyngeal, as well as by the vagus nerve, supplied basically
24:51by the external carotid artery, once by the posterior auricular artery, which is responsible
24:56for giving me a branch that tells me the mastoid style, which helps me then add what It is the
25:01middle ear so see what posterior auricular supplies both the middle ear and the external ear
25:07another branch that helps me to enervate to pardon to irrigate the space equipped and an
25:14auricular above by an error I was really referring to irrigation of the middle ear is the
25:20internal maxillary artery that internal maxillary artery gives to this branch that you are seeing here it is that would be the
25:29anterior tympanic artery which is then also responsible for reaching the middle ear this is
25:35not there it is the deep auricular it has nothing to do with it with middle ear so friend this has
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25:46the links so you can see the rest of today's videos I even give you so you can see the
25:50pharynx video and also understand the anatomy from this middle ear thank you very much for your attention