hi let's talk about the muscles of the pharynx so the best way to conceptualize the muscles of
the pharynx or the muscular walls of the pharynx is in two separate groups of muscles there's one
group the pharyngeal constrictor muscles which are largely semicircularly arranged as a set
of nesting cups where the superior pharynx will constrict your muscle nests within the middle
which nests within the inferior pharyngeal constrictor muscle these muscles serially
constrict so as to move materials distally through the lumen of the pharynx the other group are the
longitudinal muscles of the pharynx these muscles serve to both widen and foreshortened the pharynx
so as to help propel materials through it now looking at this view this is a posterior view of
the posterior pharyngeal wall we can see here's the foramen magnum of the skull the occipital
condyles we've got one set of carotid sheath contents there the other set of carotid sheath
contents there and we can see the pharyngeal constrictor muscles quite clearly so I'm going
to outline them now so this is the superior pharyngeal constrictor muscle the superior
pharyngeal constrictor muscle takes its origin from various portions of the skull and each muscle
meets its counterpart along a mid line pharyngeal we also have a middle pharyngeal constrictor
which we can see here the middle pharyngeal constrictor takes its origin from the hyoid
bone there we can see the greater cornu of the hyoid and each muscle meets its counterpart
along the single midline raphe and then we have an inferior pharyngeal constrictor muscle here
the inferior pharyngeal constrictor muscle takes its origins from the larynx and there
are two distinct parts to these muscles but they each meet their counterpart along a midline raphe
the thyropharyngeal part takes its origin from the thyroid cartilage so that would
we can see the superior horns of the thyroid cartilage here so approximately here and I'm
sorry about that bad bad selection so let's see I think it's going to extend up to here
approximately this portion of it is the thyropharyngeal part the inferior
portion is the cricopharyngeal part now before we
continue on let's erase a lot of this so I can point out some details to us
coming down laterally here we can see one of the three sets of longitudinal muscles
so this particular set of longitudinal muscles are the stylopharyngeus muscles
the style of Phrygia smuzzle x' take their origin from the styloid processes of the
temporal bone and they have their distal attachment to the thyroid cartilage of the
larynx so one of the important things to note an important relationship is that of the bulk
of the glossopharyngeal nerve so that's also from original nerve there rides down along
the posterior aspect of the stylopharyngeus muscle now the muscles of the pharynx are
innervated by the pharyngeal plexus this is a neuro plexus consisting of cranial nerve nine
which is glossopharyngeal and cranial nerve 10 or branches from cranial nerve nine and
ten which is the vagus nerve now the bulk of glossopharyngeal is a third or sensory the bulk
of Vagus is efferent or motor one of the the great exceptions here is this style of richest
muscle because stylopharyngeus is efferently innervated by the glossopharyngeal nerve
so glossopharyngeal nerve is the afferent to the pharyngeal plexus and it's the efferent to Stylopharyngeus all of the other pharyngeal constrictor and longitudinal muscles are served by the vagus
nerve in an efferent capacity from the pharyngeal plexus another thing to note within the pharyngeal
plexus is that it really doesn't apparently serve the nasopharynx the nasopharynx is going to be a
parent li served by sensory branches of the v-2 or the maxillary division of the trigeminal nerve
now these other two longitudinal muscles the palatopharyngeus and salpingpharyngeus muscles
aren't going to be visible from this particular view so i'd like to take a closer look of an
internal view of the pharynx and because it hasn't been dissected away but we can have a
better idea of of what we're dealing with here so here is the epiglottis there and we can see
there's the thyroid cartilage kind of going down along the sides there here's the uvula and then
this is an extension from the uvula of the soft palate and that's going to contain the palatopharyngeus
muscle so that palatopharyngeus muscle is going to come down like so and insert on the
superior margin of the thyroid cartilage we also have the salpingopharyngeus muscle so salingo
means horn there's an area called the salpinx which is the distal end of the eustachian tube or
the pharyngotympanic tube we really can't see it here but it would be located deep to probably
about that area and the that's up go for juice comes down and it blends with palatopharyngeus
muscle fibers on its way down the other muscular contribution that we would have laterally and this
wall has been in size would be the style of reduce muscle coming down so when these three muscles
contract they are going to elevate the out lyrics and in the process of doing so we also have a for
shortening and a widening of the pharynx so again all of these are controlled by the pharyngeal plexus
so largely going to be motor from the vagus the exception is the stylopharyngeus which is
apparently innervated by the glossopharyngeal nerve so there are two sets of pharyngeal muscles
the constrictors and the longitudinal muscles the constrictors are under the control of the
pharyngeal plexus and there is one exception to that if we go back to this sorry for that that
I should mention to you and that is that the cricopharyngeal part of the inferior pharyngeal
muscle also has innervation from the recurrent laryngeal nerve so this is an exception to the
pharyngeal plexus innervating the totality of the pharyngeal constrictor muscles but aside from
the cricopharyngeal part of the inferior pharyngeal constrictor and the stylopharyngeus muscle
the remainder of the muscles of the pharynx are innervated by the fringe
of plexus branches of vagus I guess we can consider that correct if pharyngeal part
is also a branch of Vagus I'll be a recurrent laryngeal nerve and the large exception here
to efferent innervation would be the stylopharyngeus thank you very much for your time