hi let's talk about laryngeal neurovascular in this video we'll talk about the arteries
and nerves which serve the larynx so let's start with the vasculature there are two vessels two
arteries which are serving the larynx there is the superior laryngeal artery and the inferior
laryngeal artery that's superior laryngeal artery actually is going to be served by the superior
thyroid artery and we can see that superior laryngeal artery branching from the superior
thyroid before accompanying the internal branch of superior laryngeal nerve through this hiatus
in the thyrohyoid membrane so here's the thyra hyoid membrane that superior thyroid artery is
a branch of the external carotid artery the inferior laryngeal artery is a branch of the
inferior thyroid artery that inferior thyroid artery comes from the thyra cervical trunk so
thyroid cervical trunk comes from the first part of the subclavian artery so first part
of subclavian artery to thyroid cervical trunk to inferior thyroid artery to inferior laryngeal
artery that inferior laryngeal artery ascends in the trachea esophageal groove along with the
recurrent laryngeal nerve so let's take a look at the nerves which are serving the larynx and just
to point out the the lay of the land here some of these muscles that are associated with the larynx
post early here we have the middle pharyngeal constrictor middle pharyngeal constrictor is
associated with the hyoid bone and then below that we have the inferior pharyngeal constrictor and
as you recall the inferior pharyngeal constrictor muscle has two parts there's the thyropharyngeal
part and then the cricopharyngeal part the thyropharyngeal part is associated with the thyroid
cartilage cricopharyngeal part is associated with the cricoid cartilage and these are going
up some relevance to to these nerve so let's start up here so the superior laryngeal nerve
is a branch of the vagus nerve cranial nerve 10 and it ramifies into the internal branch which
goes through this hiatus to innervate the mucosa superior to the vocal folds and that's going to
have two functions one it will be afferent from those you co see and two it will be secretomotor
to the glands of those you co see everything above the vocal folds so the vocal folds would
be approximately there the other branch of superior laryngeal nerve is the external
branch which we can see descending down here and the external branch is the oddball in terms of
the intrinsic laryngeal muscles because that is going to innervate the cricothyroid muscle
to elevate pitch that external branch of the superior laryngeal nerve also has a branch to
impart efferently served that cricopharyngeal part of the inferior pharyngeal constrictor
muscle the other source of innovation for the larynx comes from the recurrent laryngeal nerves
those recurrent laryngeal nerves are also branches of the vagus on the right side it
wraps around the subclavian artery on the left side it wraps around the concavity of
the aorta on both sides they head towards that trick you esophageal groove to a send towards
the larynx now some sources once we move or ascend beyond that inferior margin of the
cricoid cartilage will refer to the recurrent laryngeal nerve as the inferior laryngeal nerve
oops
whether it's recurrent or inferior it's the same nerve but regardless in these videos we call it
the recurrent laryngeal nerve that recurrent laryngeal nerve is going to efferntly serve
all of the intrinsic laryngeal muscles except for the cricothyroid muscle which is served by
the external branch of the superior laryngeal nerve it's also going to be afferent from the
mucosa of the lyrics below the vocal folds and it will be secrete a motor to those folds as
well or to the mucosa below those folds as well in addition recurrent laryngeal
nerve has a branch that also apparently serves that cricopharyngeal part of inferior fringing
constrictor so the external branch is superior laryngeal nerve the recurrent laryngeal nerve as
well as the pharyngeal plexus all will serve that cricopharyngeal part which is pretty impressive
in terms of overall innervation and that leads us to our assessment question for the video and
that is the inferior laryngeal artery is a branch of the inferior thyroid artery which
is sourced from which artery brachiocephalic trunk that seems a little too general external
carotid well that's the superior thyroid so that's wrong thorough cervical trunk
you inferior thyroid artery is a branch of the thyroid cervical trunk so that's that sounded
good to me and transverse cervical artery but only 30 percent of the time - that's that's a
distractor as well so the correct answer is that the inferior laryngeal artery and inferior thyroid
arteries ultimately sourced from the thyroid cervical trunk thank you very much for your time