YT YouTube2Text

YouTube2Text → Transcripts → Gross Anatomy of the Middle Ear - Boundaries ,Contents and Functions ( Animation ) | USMLE Step 1

Gross Anatomy of the Middle Ear - Boundaries ,Contents and Functions ( Animation ) | USMLE Step 1 — Transcript

by Dr.G Bhanu Prakash Animated Medical Videos · 1,969 words · 339 segments · language en · Watch on YouTube

Open in transcriber Summarize with AI Download SRT/VTT

Full transcript

0:00[Music]
0:07anatomy of the middle ear
0:10the air is structurally divided into
0:14three parts
0:15the outer part
0:17the outer part is made up of the pinna
0:20as well as the external auditory canal
0:24the next one is the middle ear
0:26the place where i am standing is called
0:28as the middle ear or the tympanic cavity
0:31and
0:32the final structure of the ear is the
0:35inner ear so like this the ear is
0:37divided into three parts called as outer
0:40middle and the inner ear
0:42so here this video is going to focus
0:45especially on the anatomical aspects of
0:48the middle ear so where we are going to
0:50discuss about their boundaries contents
0:53as well as the blood supply
0:55and the supply of the middle ear
0:58so the middle ear actually extends from
1:02the tympanic membrane because tympanic
1:04membrane is the lateral structure of the
1:06middle ear and it extends towards the
1:09inner ear that is lateral structure of
1:11the or the lateral wall of the inner ear
1:14so what are the extensions of the middle
1:16ear guys
1:17it extends from
1:19tympanic membrane laterally
1:21as well as to the lateral wall of the
1:24inner ear medially right this is where
1:27you can see the middle ear cavity which
1:30is called as the tympanic cavity
1:33now coming towards the divisions of the
1:36middle ear
1:37the middle ear can be divided into two
1:40parts
1:42the first one is called as the tympanic
1:43cavity
1:44and second one is called as
1:46epi tympanic rhesus
1:48so now let us discuss about the tympanic
1:51cavity
1:53the tympanic cavity is also called as
1:56the tympanum
1:58so here
1:59the tympanum is nothing but
2:02is a pneumatized region
2:05so what is the meaning of the
2:06pneumatized region here it is nothing
2:08but the air filled region of the
2:11temporal bone
2:12that lies
2:14just medium to that of the tympanic
2:16membrane
2:17what is the tympanic membrane we will
2:20also call the tympanic membrane as the
2:23eardrum
2:25so remember that the tympanic membrane
2:27is also called as eardrum the middle ear
2:29is located
2:30later to that of the promontory
2:33so what is the promontory the promotory
2:36it is nothing but caused by
2:38the terms of the cochlea of the inner
2:42ear
2:43so now let us talk about the tegmen
2:45tympani
2:47the tegman timpani is nothing but a
2:50laminar projection
2:52of the petrus part of the temporal bone
2:55that forms the roof of the middle ear
2:58cavity is nothing but called as the
3:00tegman timpani it is the laminar
3:03projection of the petrus parts of the
3:06temporal bone which forms the roof
3:10and it contains
3:12especially if you see here the middle
3:13ear contains there are three important
3:16bones
3:17the malleus
3:18incus and stapes which transmits the
3:21sound vibrations from the tympanic
3:24membrane extending towards the inner air
3:27by means of these three important tiny
3:30bones which are present in the middle
3:32ear
3:33now let us talk about epi tympanic
3:35rhesus which is the another division of
3:38the tympanic cavity right one is the
3:42tympanum and second one is called as the
3:44epi tympanic races
3:46so this epi tympanic vases is nothing
3:49but a space
3:51which is located superior to that of the
3:54tympanic cavity
3:56and which lies adjacent to the mastoid
3:59air cells
4:01and here the ear ossicles such as
4:03malleus
4:04incus partially extend upwards into the
4:08epi tympanic races so this is how the
4:12middle ear cavity can be divided into
4:15the tympanum as well as epi tympanic
4:18races
4:20now we shall discuss about the
4:22boundaries of the middle ear
4:25for better understanding the middle ear
4:28can be visualized as a rectangular box
4:32so here you can see
4:33it looks like
4:35a rectangular box
4:37which has a roof
4:38which has a floor
4:40which also has
4:42the medial wall this is the medial wall
4:45and the lateral wall is open which is
4:46formed by the chimpanic membrane and
4:49also it has the anterior wall and also
4:51it has the posterior wall
4:54so like this the middle ear totally has
4:56six walls
4:58so now we have to discuss what are the
5:00structures which are formed
5:02whenever we are talking about these
5:04boundaries of the middle ear
5:06first let us discuss about the roof of
5:09the middle ear cavity
5:11the roof is also called as
5:13the tegmental wall
5:16remember that the pigmental wall forms
5:19the roof of the middle ear cavity also
5:23known as the tympanic cavity
5:25so why we are calling it as a tegmental
5:27wall
5:28because it is formed by the
5:30tegmentimpany
5:32which is nothing but a thin plate of the
5:35petrus part of the temporal bone that
5:38forms the roof of the canal for the
5:40tensor tympani muzzle and the tympanic
5:43antrum
5:44so this is the wall which means the roof
5:46is the one which separates the dura
5:49mater which is lying at the floor of the
5:52middle cranial fossa from the tympanic
5:55cavity and above that what you can see
5:57is the cerebral cortex
6:00so after this after discussing about the
6:03roof now let us discuss about the floor
6:06of the middle ear cavity
6:08so as we said that
6:10the tegmental wall is called as the roof
6:13the jugular wall is called as the floor
6:16the floor is called as jugular wall so
6:20it is formed by
6:22a thin layer of the bone we can see very
6:24clearly here a thin layer of the bone
6:27which separates this particular tympanic
6:30cavity from the superior bulb of the
6:34internal jugular vein which means the
6:37internal jugular vein as well as the
6:39tympanic cavity that is the middle ear
6:41cavity is separated by a thin layer of
6:44the bone called as jugular wall so this
6:48is the roof as well as floor of the
6:51middle ear cavity
6:53and next one is called as the membranous
6:55wall
6:56the membranous wall is the lateral wall
6:59so as you can see me inside the middle
7:01ear cavity
7:02the lateral wall is opened or formed by
7:05the tympanic membrane so why are we
7:07calling it as a membranous fall
7:09because it is entirely formed by a
7:12peaked convexity of the tympanic
7:15membrane and superiorly by the lateral
7:18body wall of the epi tympanic races so
7:22the epi tympanic creases as well as the
7:24tympanic membrane this is what it
7:26actually forms the lateral wall of the
7:29middle ear cavity so after the lateral
7:31wall now we have to see what is the
7:33medial wall right so this medial wall is
7:36called as the labyrinth involved so the
7:38entire structure the entire the wall
7:41what you are seeing here which is called
7:43as the medial wall
7:45this medial wall is called as the
7:47labyrinthine wall
7:49so this is the wall it separates this
7:52particular tympanic cavity from the
7:54inner ear
7:56so the initial part that is the basal
7:58turn of the cochlea
8:00forms the promontory of the labyrinthine
8:03wall here and we can also see some of
8:06the important structures like round
8:08window as well as oval window right
8:11promontory round window oval window all
8:13these are the structures what we can
8:15clearly visualize
8:17on the medial wall of the middle ear
8:20right we can see the oval window as well
8:22as round window over here which
8:24communicates with the inner ear so here
8:27we have to discuss little bit more
8:29detail about the round window as well as
8:31the oval window
8:33so first let's discuss about the round
8:34window here we can see the structure
8:37right
8:38so
8:39round window is one of the two openings
8:41which are seen on the medial wall of the
8:44middle ear
8:46that is it is nothing but a part which
8:48is separating the middle ear to the
8:50inner ear
8:52and this wall and this particular
8:55structure
8:56is sealed by a secondary tympanic
8:59membrane which is also called as round
9:02window membrane
9:04so this is the membrane which actually
9:06vibrates with opposite phase vibrations
9:10entering the inner ear through the oval
9:12window
9:13and this particular structure allows the
9:16fluid into the cochlea to move which in
9:19turn it ensures the hair cells of the
9:21basilar membrane will be stimulated and
9:24the audition will occur that is the
9:27importance of the round window
9:29and next structure is called as the oval
9:32window
9:33oval window is also called as fine straw
9:36vegetable eye
9:37so the oval window is also a membrane
9:40covered opening
9:42that leads the middle ear to the
9:44vestibule of the inner ear over here
9:48so the vibrations that contact the
9:50tympanic membrane travel through the
9:53ossicles and it enters into the inner
9:56ear
9:57and the oval window is nothing but
9:59called as an intersection of the middle
10:02ear with the inner ear and it is
10:04directly contacted by the stapes because
10:07it is covered by the food plate of the
10:10staples so this is what we need to know
10:12about the round window as well as the
10:15oval window so after discussing about
10:17the medial wall
10:19next let us concentrate on the posterior
10:22wall of the tympanic cavity
10:24the mastoid wall is also called as the
10:26posterior wall of the middle ear
10:29so this is the wall which features the
10:31adjectives which is the opening to the
10:34mastoid antrum in its superior part
10:37which connects to the tympanic cavity
10:39especially to the mastoid air cells
10:43and also we can appreciate the canal of
10:45the facial nerve
10:47which descends between the posterior
10:50wall and the antrum medial to the top
10:52adjectives
10:54so above this particular canal what we
10:57can see is the lateral semicircle canal
11:00and below the additives there is a
11:03hollow conical projection called as a
11:05pyramid
11:06which is perforated by the tendon of the
11:09stapedius muscle so these are the
11:11structures what we can identify on the
11:14posterior wall of the middle ear cavity
11:17at last we have to discuss about
11:20the anterior wall of the middle ear
11:22cavity which is also called as the
11:24carotid wall
11:26so this is the wall that separates the
11:28tympanic cavity from the carotid canal
11:31so what is the carotid canal here
11:34the carotid canal is a passageway
11:37in the temporal bone through which the
11:40internal carotid artery enters the
11:42middle cranial fossa from the neck
11:45so this anterior wall is also termed as
11:48a corroded wall because
11:50there is a thin plate of the bone that
11:52separates the carotid canal from the
11:55tympanic cavity and this particular wall
11:58is perforated by the tympanic branch of
12:01the internal carotid artery and also the
12:04d petrosal nerve
12:06so this is what we need to discuss about
12:09the anterior wall of the middle ear
12:12cavity by this we completed all the six
12:15boundaries of the middle ear cavity
12:17which is also known as the tympanic
12:19cavity
12:21after discussing all the boundaries of
12:23the middle ear
12:25let's enumerate the functions of the
12:27middle ear cavity
12:29the primary function of the middle ear
12:32is to offset the decrease in the
12:34acoustic energy
12:36that would occur if the low impedance
12:38ear canal directly contacted the high
12:42impedance cochlear fluid
12:44so when the sound waves are transferred
12:47from low impedance medium that is air
12:51to the high impedance medium example
12:53that is water
12:54a considerable amount of energy
12:57is reflected
12:58and fails to enter the liquid
13:01so if there is no middle ear where
13:03present
13:05only 0.1 percent of the acoustic wave
13:08energy
13:08traveled through the air would enter the
13:11fluid of the cochlea and 99.9 percent
13:14would be reflected so that is the chief
13:17function of the middle ear cavity and
13:20the middle ear also able to dampen the
13:23sound conduction substantially
13:25when faced with a very loud sound by
13:28noise induced reflex contraction of the
13:31middle ear muscles so these are the two
13:34important functions what we need to know
13:36about the middle ear so by this we
13:38completed the anatomy of the middle ear

About this transcript

This page contains the full transcript of Gross Anatomy of the Middle Ear - Boundaries ,Contents and Functions ( Animation ) | USMLE Step 1 by Dr.G Bhanu Prakash Animated Medical Videos, generated from the public captions YouTube serves with the video. The transcript has 1,969 words across 339 segments, with the original timestamps preserved so you can click any line to jump to that moment in the embedded player.

What you can do with it

Use the transcript to take notes, quote the speaker, build a study guide, generate a summary with ChatGPT or Claude via the YouTube Summary tool, or export it as a timed subtitle file with YouTube to SRT. You can also re-open it in the transcriber to translate the transcript into 100+ languages.

Free YouTube transcript tool

YouTube2Text is a free YouTube transcript generator — no signup, no daily limit. Paste any YouTube link and get the full transcript instantly, with timestamps, click-to-jump, translation to 100+ languages, AI prompts for ChatGPT, Claude, and Gemini, and exports to TXT, SRT, VTT, or Markdown.