hello all it is dr. Alsup here and we are going to discuss the muscles we need to identify for
the parotid gland and submandibular triangle session these are mostly suprahyoid muscles so
those muscles above or superior to the hyoid with an inner extrinsic tongue muscle thrown in there
for good measure so let's get started so we're looking at a lateral view kind of inferior lateral
and you will see the base of the mandible right here and portions of the hyoid bone right here
with a lot of connective tissue associated with it and we're going to focus on this suprahyoid
region here and one of the most dominant muscles in this area is the digastric and in this view
you can really see both the anterior as well as the posterior portions of or posterior bellies
excuse me of the digastric muscle connected by this intermediate tendon right here so you can
see that it's a fairly long muscle the anterior belly is going to attach to the mandible which
you can see it heading in that direction with the posterior belly being attached all the way
to the mastoid notch of the temporal bone the intermediate tendon is anchored to the hyoid
bone via a fibrous loop which you can't really see very well here and recall that the formation
of these bellies are unique in that they are going to be developed through two different
foreign geol arches so each belly has a separate innervation which is quite unique the anterior
belly is innervated by the nerve to mylohyoid which is a branch of v3 whereas the posterior
belly is going to be innervated by an official nerve so that's something that we love to talk
about anytime that you have something unique like that or two separate innovations or an innovation
that's different from the rest of the surrounding muscles that's something that you'll hear us often
talk about returning to the intermediate tendon region you will get to really see the stylohyoid
muscle which is going to be right about here ish extending into this region so this is stylohyoid
the stylohyoid is actually going to divide around the intermediate tendon and for the majority of
its course it will run medial and parallel to the posterior belly of the digastric and with them
being so close in location it makes sense that this muscle is going to have a similar innervation
to the posterior belly as in the cranial cranial nerve seven okay looking at an anterior view
here and a more lateral view here let's focus on identifying the mylohyoid muscle but before doing
that it is hard to avoid the anterior belly of the digastric so let's get that one kind of out of the
way so there's an anterior belly anterior belly here deep or really its superior to the anterior
belly is the mylohyoid muscle so you can see the mylohyoid muscle here and it will extend into this
region in this region and the mylohyoid right here it is forming as you can see here the bulk of the
floor of the oral cavity so if you went superior to this muscle you are getting into portions of
the oral cavity it like the anterior belly of the digastric muscle will be innervated by the nerve
to the mylohyoid which is a branch of v3 lastly let's get a sneak peek at an extrinsic tongue
muscle which we will see in a bit more detail in the oral cavity session and this is going
to be the hyoglosses muscle you can see a little bit of it there and a little there you can
see the lingual artery which is right here diving deep to the muscle so that's going to be the
hyoglosses it is going to extend from the greater Horn and body of the hyoid bone to the side of the
tongue so it makes sense that we'll see a little bit better in the oral cavity session but you can
see it here and we did want to bring it up since it does have that relationship with the lingual
artery you can also see the mylohyoid muscle in this view right here with the hypoglossal
nerve diving deep to that muscle and here is that anterior belly of the digastric which has
which you can still see the the full extent of that but that intermediate tendon has been cut
in this particular dissection so those are the muscles you need to identify in this session most
we will review and see in different views in the upcoming oral cavity session but since you have
these in the submandibular triangle or submental triangle regions we want you to begin getting
familiar with these thank you all for your time and please reach out if you have any questions