00:01
Cranial nerve VII
or the facial nerve
is also going to
have multiple nuclei
reflecting the fact
that facial nerve
carries out a lot of
different types of innovation.
00:13
Here we see the infratemporal
course of the facial nerve.
00:18
This is where it's going to go
through the internal acoustic meatus
along with cranial nerve VIII,
as we'll see in a second.
00:26
And it's going to travel
through this portion of bone
to reach something called
the geniculate ganglion.
00:32
At this point, it will go through
the facial canal for the most part,
to eventually emerge
through an opening
between the styloid process
and the mastoid process
called the stylomastoid foramen.
00:45
At the level that
geniculate ganglion,
it will go off a
little tiny branch
that's going to form
a little anastomosis
at the pterygopalatine ganglion
with the trigeminal nerve.
00:57
There's also going to
be a little tiny branch
going off to a very tiny
muscle called the stapedius.
01:03
So it's going to be
the stapedial nerve.
01:07
There's also a tiny branch
that's going to branch off very
early called the chorda tympani.
01:12
So called because it's going to
pass behind the tympanic membrane
to join up with the lingual nerve
on its way towards the tongue,
where cranial nerve VII can
provide some taste sensation
to the anterior tongue,
as well as parasympathetic
innervation
of some of the salivary glands.
01:32
The majority of the facial
nerve, as we mentioned,
will come out the style
of mastoid foramen,
and it's going to do so right at
the level of the parotid gland.
01:43
And it's going to enter in branch
essentially within this gland.
01:48
And it's going to give
rise to several branches
such as the posterior auricular,
temporal, zygomatic, buccal,
mandibular, and
cervical branches.
01:59
It's also going to
give rise to branches
going off to the gastric muscle,
the posterior belly of
the digastric muscle
and the stylohyoid muscle
for which it provides
motor innervation.
02:13
In addition to
motor innervation,
of what's called the muscles
of facial expression,
there are a lot of visceral efferents
and afferents of the facial nerve.
02:24
For example, there's going to
be parasympathetic innervation
of the lacrimal gland,
innervation of the nasal glands,
parasympathetic innervation
to the sublingual and
submandibular glands,
as well as special
or taste sensation
from the anterior
two-thirds of the tongue.