Okay, that’s about lymph nodes.
Moving up into the face. To understand the
anatomy of the face at your level, you need
to have a bit of understanding about the cranial
fossa, as well as the foramen. That leads to
your cranial nerves. So, your cranial fossa
has got an anterior cranial fossa at the front,
middle cranial fossa and posterior cranial
fossa. What is the first cranial nerve?
Olfactory. What’s the function, action of
Smell. Where does it, how does it come in
to the nose for the function? Starts from the skull
base through the cribriform.
Yeah, it sends fibers through the cribriform
plate. It doesn’t have
a foramen, it comes through the cribriform
plate. So that’s why when you have base
of skull fracture, you have CSF leak coming
through the nose because of fracture of
cribriform plate. So the olfactory, it
just got those sensory fibers into the nose
coming through the cribriform plate. Okay,
that’s all you need to know. Second is optic.
Optic comes out through? Optic.
Optic canal. Does it accompany
Ophthalmic artery. Ophthalmic artery, very
good. Where does ophthalmic
artery come from?
First branch of internal carotid.
Very good. Tell me, branch of the? It’s
a branch of internal carotid. So there’s
your ophthalmic, coming out through optic
canal, accompanied with ophthalmic artery.
What’s next? Oculomotor. So tell me
how oculomotor comes out?
Superior orbital fissure. Very good.
Okay, tell me what are the other
structures in the superior orbital fissure.
Cranial nerves III, IV, VI, V1, emissary veins,
I don’t know.
You’re right, pretty much, you got all the
important ones. And then you have the superior
and inferior ophthalmic veins which for the
purpose of your part you don’t need to worry
too much but you need know three, that’s
your occulomotor, abducens and trochlear.
So III, IV, and VI cranial nerves
as well as the first division of the trigeminal
comes out through the superior orbital fissure
So III, IV, first part of V and VI.
Trigeminal nerve has got three components,
ophthalmic, maxillary, mandibular. So ophthalmic
is the one that you said comes out of the
superior orbital fissure. So when you are
anesthetizing somebody’s forehead to excise
a lipoma here, what nerve are you anesthetizing?
It has to be from the ophthalmic division of trigeminal.
So it is normally your supraorbital
and the supratrochlear nerves, because they
are the ones you are anesthetizing when you
are doing anything in the forehead, okay?
You also have lacrimal gland branches, ethmoidal,
but you don’t have to go into detail. All
you need to remember for this exam is
superior orbital fissure, what are the
nerves that come out. We have covered I, II,
III, IV, V, VI. Okay what’s next? Seventh
cranial nerve, the facial nerve. How does it
come out? It comes, I think through the
internal acoustic meatus?
Internal acoustic meatus.
And there’s a facial canal?
It’s the facial canal.
Well then, it gives off a tympanic branch
and then it sends through the stylomastoid
foramen branch off into five branches.
Okay, that’s very good. I think we will
come to the facial nerve branches when we
do the face, but at this point you need to
remember how does it come out. So facial nerve
comes out the internal acoustic meatus along
with the 8th cranial nerve, with the vestibulocochlear.
So VII and VIII comes out of the internal
acoustic meatus. The VIII cranial nerve stops
at the middle ear, it doesn’t come out
further than that. VII cranial nerve, which
is the facial, come enters the facial canal,
then comes out the stylomastoid foramen and
then it comes to the face.
It gives a few branches inside. One is your
nerve to stapedius, anything else? This is
quite important. Facial nerve is quite an
important nerve. So you need to know a bit
more about the facial nerve. Now I’m sure
all of you know this, the branches, that’s
after it comes out from stylomastoid foramen
but before that, think about it. Nerve to
stapedius, one, second is the chorda tympani.
Chorda tympani. So what does this chorda
tympani do, apart from taste to the --
Taste and something else.
Soft palate sensation? Soft palate and tonsils.
Yes, you can get sensation to the palate as
well, but anything to do with submandibular gland?
That’s right. It sends parasympathetic fibers
to the submandibular gland as well, so
that’s part of the facial nerve coming through
the chorda tympani. Any other branch? So nerve
to stapedius, chorda tympani and one more
important branch, greater petrosal nerve,
okay? Greater petrosal nerve. What does that
do? Greater petrosal nerve predominantly carries
preganglionic parasympathetic fibers.
Yes, to the lacrimal gland, to the lateral
side of the nose, to the ethmoidal region here.
So, that’s actually when you get hay
fever, your tears, runny nose, it’s all
due to the greater petrosal nerve, which is
a branch of the facial, okay? Right, VIII
cranial nerve we discussed vestibulocochlear.
What’s IX? Glossopharyngeal. How does it
From the --
Is it the jugular canal?
Okay, what other nerves coming out of jugular
IX, X, XI, okay? IX, X, XI cranial nerves
come out through the jugular foramen.
Then of course you have the internal jugular vein
going in, and is also accompanied by the ascending
pharyngeal artery, okay? So, jugular foramen
is quite big, quite important. So three cranial
nerves coming out, the jugular vein going
in, along with the ascending pharyngeal artery.
So that’s IX, X, XI. XII, hypoglossal
nerve comes out through the hypoglossal canal.
Question, should we also learn the cavernous
sinus as well, what is that?
3rd, 4th and yeah. So these are the main nerves.