hi let's talk about the larynx and the laryngoskeleton
in this video we'll discuss the larynx where it's located and its functions we'll also discuss the
laryngoskeleton and its constituent cartilages and their features so the larynx colloquially known
as the voice box sits inferior to the hyoid bone it's actually suspended from the hyoid bone by the
thyrohyoid membrane which attaches to the thyroid cartilage of the larynx
it's superior to the trachea and it helps to suspend the trachea by the cricotracheal ligament
and it's sitting anterior to the laryngopharynx which would be approximately here
this is in line with the cervical vertebral levels of approximately c4
through c6 but in some individuals the larynx may be elevated and in others it may be depressed
so the larynx consists of a laryngoskeleton as well as
intrinsic membranes and connective tissues as well as various intrinsic muscles and so let's outline
some of those elements of the laryngoskeleton or the cartilaginous framework of the larynx so there
are going to be three major unpaired cartilaginous elements these include the thyroid cartilage the
epiglottic cartilage and the cricoid cartilage the remaining cartilages are
all bilaterally paired so sitting atop the posterior aspect of the cricoid cartilage is
or are the arytenoid cartilages these are sort of funnel shaped and atop the arytenoid
cartilages are the corniculate cartilages and then between the arytenoid cartilages and the
epiglottis are these airy epiglottic folds and within those folds are the cuneiform cartilages
and there may be other smaller cartilages that that more typically or less typically
appear throughout the larynx but these are the the major elements of the laryngoskeleton
these cartilaginous elements are hyaline cartilage and as in individual ages starting
at about 18 years of age they begin the process of calcification so let's take a look at some
of the features of the laryngoskeleton let me just outline for you here this is the thyroid cartilage
the thyroid cartilage consists of two laminae that come together along the midline that midline
can sometimes be very robust especially in individuals with a lot of testosterone
because testosterone builds muscle mass and muscle pulls on various features of the of the skeletal
system and cartilage to exacerbate them and so that's the laryngeal prominence aka adam's apple
looking posteriorly they're going to be two sets of horns a superior horn the superior
horn is in line with the greater horn of the hyoid bone so these two are going to articulate
with an intermediate thyrohyoid membrane so there's the thyrohyoid membrane
and then that inferior horn is going to form a joint with the cricoid cartilage there
so that's the cricothyroid joint upon which the cricothyroid muscles which are intrinsic
muscles of the larynx can work and so when these muscles fire the thyroid cartilage
tips anteriorly and inferiorly and that's going to put tension on vocal folds to increase pitch
the cricoid cartilage um cricoid comes from cracios which means a ring is the
only cartilage to completely surround the airway uh within the larynx so it is 360 degrees complete
posteriorly upon the cricoid cartilage are where the arytenoid cartilages are going to sit
and then we can't see this very well here but let me just kind of
the epiglottic cartilage has a stem and a leaf and it's going to articulate anteriorly with
the thyroid cartilage and it is going to form a good part of the laryngeal inlet here along with
the ary-epiglottic folds and the corniculate cartilages that are atop the arena cartilage
so here is the laryngeal inlet that's for gas exchange between the larynx and the laryngopharynx
so let's take a little closer look at some of these elements so here from the post here we
can still see the corniculate cartilages that help to support these airy epiglottic folds
we have cuneiform cartilages embedded in those area epiglottic folds to maintain
a little bit of patency we can see the posterior aspect of the thyroid cartilages
there and where they articulate via their inferior horns with a cricoid cartilage over here is i
i think a really excellent view of things so here is the thyroid cartilage here is the
cricoid cartilage and sitting atop the cricoid cartilage we can see the arytenoid cartilages the
arytenoid cartilages are sort of the stars of the show with respect to sound production or phonation
from the larynx these are very kinetic they can glide they can pivot and it's probably important
that uh you realize that there are two processes associated with the arithmetic cartilages
anteriorly there are vocal processes and laterally you probably see this better here laterally there
are muscular processes so there's the muscular process there's the vocal process the vocal
process actually attaches the vocal ligament to the arytenoid cartilage and that goes out to the
thyroid cartilage it's my dog just shaking your head and we can see those vocal ligaments there
when those vocal ligaments are invested by mucosa they become vocal folds you probably know them
best as vocal cords those are the structures which are going to vibrate during phonation and
so depending on what those arytenoid cartilages are doing those vocal folds can either a deduct
so as to produce a maximally patent airway or they can a deduct adduct so that we can bring the folds
into close association with one another for phonation and that leads us to our
assessment question and that is most intrinsic laryngeal muscles are able to affect phonation
due to their attachment to which laryngeal cartilage is it a well that sounds pretty
good to me b cricoid well we'll see how a lot of intrinsic laryngeal muscles also attach to the
cricoid cartilage that's a pretty good answer can a form no epiglottic no thyroid cartilage
some of them been not too many so really we're limited to a retinoid in cricoid and if this were
a discussion of the intrinsic laryngeal muscles uh we would probably have a more thorough background
on which to make this decision but suffice it to say the arena cartilages are the ones that are the
most dynamic they have the most intrinsic laryngeal muscles attached to them so
i would say a aretenoid cartilage best answer thank you very much for your time