hello everyone this is dr o and in this video we're going to talk
about how the ear is related to the tmj or the temporomandibular joint
and to the nasal pharynx specifically we'll be focusing on the external and the middle ear
so first off with the external ear this is something i talked about a little bit ago
in the temporomandibular joint lecture in that the ear is very closely in relation to
the temporomandibular joint so we'll remember here
here is our mandibular condyle sitting within the mandibular fossa of the temporal bone
and then just posterior to that we find our external acoustic meatus
so someone who is experiencing pain from a temporal
mandibular disorder often will experience pain within the ear
the middle ear is also closely related to the tmj and we'll talk specifically about
the openings that real that connect between the area of the tmj and the middle ear
so the first one we see here is this pinpoint right about there we can see it represented over
here on the left side so there's a tiny red dot on the right image here now the tympanic canaliculus
is related to the glossopharyngeal nerve which you'll remember exits from the jugular foramen so
it'll come out here and give off its branch which will then re-enter into the middle ear and that
branch is the tympanic nerve i also want to note the other kind of closely related structure here
is this opening let me see it on the left image as well and that is the carotid canal opening
the second opening is the petro tympanic fissure so this line running right along
here you'll remember is kind of within the mandibular fossa or just posterior to it
we see the line on the image on the left represented as well
and this will carry chorda tympani from the middle ear out into the infra-temporal fossa
where it will then join with the lingual nerve so remember chorda tympani is a branch of the
facial nerve and then we'll exit the middle ear into the infra-temporal
fossa now along with the tmj the middle ear is also closely related to the nasopharynx and this
is through the pharyngotympanic or you may have also heard the eustachian tube or the auditory
tube now just as a note eustachian is an eponym so it's named after someone pharyngotympanic tells us
a little bit more about what is connected between this tube so the two areas connected by the
pharyngotympanic tube are this space we find just posterior to the nasal cavity and the oral cavity
that would be the pharynx and the tympanic refers to the tympanic cavity or the middle ear space
so the pharyngotymponic tube is responsible for equalizing pressure between this middle ear which
is full of air in the external environment or you can think about trying to equalize the
pressure of the middle ear with the atmospheric pressure so typically you'll find that this is
actually a closed space but there is not air constantly going out and into the middle ear
only when needed is that push to open and think about the last time you flew in a plane
or you walked up a mountain or did anything where the atmospheric pressure changed for you
and what you note is you get that kind of discomfort in your ear and what are some of
the things that you might do to help with that so i personally every single time i fly when we
take off i start chewing gum and then when we're about to land i have to start chewing gum as well
and that chewing will get things moving so chewing and swallowing and yawning all of
those movements move the palette which we'd find kind of in that space the soft palate
and a lot of the soft palate muscles will attach to the pharyngotympanic tube
so the act of swallowing and the act of yawning and opening that
up really can allow for air to exchange between the two cavities
this other view shows us where that opening is in the pharynx
so this opening right here we can remember that here about is the nasal cavity
and then posterior to that line i have here is the nasopharynx so that is the opening
to the franco-tympanic tube right above that opening and around it we see a bit of a bump
there's more on this in a little bit but that is related to the cartilage of the
pharyngotympanic tube and we're seeing is the mucosa covering over that cartilage
all right so i told you i would try to connect a lot of these things back to that
first video what i want you to answer here is the question from which wall of the middle ear
does the pharyngotympanic tube project is it the anterior wall the lateral wall
the medial wall or the posterior wall so pause so you can give yourself a second to think
when you're ready let's label some of the walls we can see first so first off right away
look for that tympanic membrane tympanic membrane what wall are we thinking of there
so that is the lateral wall what about these kind of structures along in here you can kind of
see poking through our parts of the cochlea and the semicircular canals that is our medial wall
so which way are we looking at this well let's point to kind of just so what we can see from
above this right here is the portion of the zygomatic arch coming from the temporal bone
and this back here is the mastoid process and that's the styloid process so what i'm kind
of trying to show you is that this is posterior and this is anterior so the correct answer here
is anterior when we're thinking about that anterior wall we're thinking about this muscle
which one is that so that's the tensor tympani muscle attached to the cartilage
of the pharyngotympanic tube here so the correct answer here is the anterior wall
now it's not represented here but what other structure is just anterior to the middle ear
so the one i'm thinking about is the carotid canal containing the internal carotid artery
all right thank you so much for joining me here
and let me know reach out with any questions you might have have a great rest of your day