MARIAN DIAMOND: Good morning.
Another lovely
morning, isn't it?
It's lovely down at UCLA, too.
Just to know that they
also have nice weather.
Can everybody hear
me back there?
No?
I can tell by the looks
on their faces they can't.
Can you please adjust the mic?
Somehow?
I'll keep talking
until it goes up.
Is that right?
Is it coming through?
Can you hear me in back?
No, there's still no response.
Can you hear me now?
STUDENT: Yes!
MARIAN DIAMOND: Yes, thank you.
That's my friend back there.
He usually sits up
here, so he talks to me.
Now he's way back there.
Thank you.
Let's see.
We have Jacqueline DeSolier.
Is Jacqueline here?
No Jacqueline.
Sometimes they come in
late and come up afterward,
so we have to take
three instead of two.
Let's see then.
Is Carolyn Wynn here?
There's Carolyn.
All right, perfect.
We'll see you after
class, Carolyn.
Then we have Kenneth Ruth.
Is Kenneth here?
There's Ken, fine.
Well, you'll meet Carolyn who's
just right behind you there.
So come up after class please.
Let's continue now with
our cranial nerves.
First, we'll do a little
review, because we've given them
to you several times from
different directions, but just
to bring them together now.
So cranial nerves.
You recall, we had
a forebrain, we had
a midbrain, and a hindbrain.
Which cranial nerves were
dealing with the forebrain?
What's the very first one?
One and two.
How about the midbrain?
What cranial nerves are
functioning with the midbrain?
You can guess at least one.
Three and four.
Three and four
are both midbrain.
So look at, then.
Hindbrain will have 5, 6,
7, 8, 9, 10, 11, and 12.
So you can see when you
get an injury in one
of these special divisions what
happens when you injue here
and how many of your cranial
nerves can be affected.
Clinically, this is one of
the most important things
I can tell you, to know where
your cranial nerves are coming
from.
So if you see a peripheral
expression of a cranial nerve,
you know what part of the
brain is having problems.
It's the quickest way.
So this gives you just the
idea of how these are divided.
Now what we want to do
is just go through them
and give their names and
brief functions for each.
So these are specific
cranial nerves.
We said one was olfaction,
the olfactory nerve.
Obviously, it helps us smell.
But I was just thinking
about its derivative.
If we are adding on our
spinal cord with evolution,
and one is coming from the
most recent part of the brain,
and yet you'd think
that olfaction
is so important for
survival and for sex.
Yet, it's way up there,
the last to develop.
So the optic nerve is two.
Optic obviously for vision.
Three, what's three?
Ocular motor, oculomotor,
what does it do?
Oculo, eye mover.
So it will go to four of the six
extraocular eye muscles, four
of six extraocular eye muscles.
So to give you those briefly
here's our eye, pupil.
We'll have a superior
rectus up here.
Rectus was straight,
you remember
from your rectus abdominus.
This is superior rectus.
We have an inferior rectus.
Just to make this easy for
you, we have a medial rectus
and we have an inferior oblique.
So it's going to be
going in this direction.
Inferior oblique.
So this gives us our four, one,
two, three, four, extraocular
muscles that are all
supplied by three.
So let's go on to four.
Four is trochlear.
What does trochlear mean?
Pardon?
No, good guess, but wrong.
Pulley.
Pulley, because when
you see the trochlear,
it works like a little pulley
to rotate the superior oblique.
So until you see it, it
doesn't make much difference.
But once you see it,
you'll never forget it.
So this is to one
extraocular eye muscle.
It will be the superior
oblique, so it's up here.
Superior oblique.
So we'll put it here.
[INAUDIBLE] repeat,
repeat, repeat.
All right, so we've got five
of our extraocular eye muscles.
Let's go to our
fifth cranial nerve.
What's it called?
Trigeminal.
It's got three parts.
Trigeminal.
So we're going to have a
motive component, motor five.
Does anybody know where
motor five goes to?
Muscles of mastication.
Get lock jaw if
you disturb this.
Muscles of mastication.
What are your muscles
of mastication?
Pardon?
Chewing, that's what it means.
But what are the muscles
that are helping you chew?
That's OK.
Masseter and temporalis.
Sure, you've had them.
So now sensory, this will be
sensory to the face and sensory
to the nasal.
What other cavity?
Oral cavity.
So sensory to the face,
we'll just do it quickly.
Whoops.
Not that quickly.
[CHUCKLING]
I got carried away there.
So if we take this part,
this part, it's trigeminal.
This will be the
opthalmic division.
This will be the
maxillary division.
That's easy, just upper jaw.
Face over upper jaw.
The mandibular division,
just to give you
the origin of the term, with
its three sensory components
for the face.
Let's look at six.
Six is abducins.
What does ab mean?
Away.
So what muscle is
missing on our eyeball?
The lateral rectus, right.
So abducins will be the
lateral rectus eye muscle.
We can put it in our drawing.
It's going to be over here.
This is lateral rectus.
It's easy.
I can't spell it.
Rectus.
So what happens if we cut
the sixth cranial nerve?
How can you tell when the
person comes into your office
if they have a
sixth nerve defect?
No, just the opposite.
You don't have lateral
to pull it sideways.
Therefore, medial is
pulling, so you have what's
called medial strabismus.
Can anyone just have
one eye do strabismus?
Strabismus, you
know, is cross-eyed.
I can do both together,
but I can't do--
I frequently get a student.
Everybody comes and
looks, because they
can bring that one over.
But nobody in this class?
No?
Maybe you haven't tried.
But anyhow, so injury
here, just to give you
the dynamics of
knowing cranial nerves,
will be medial strabismus,
medial cross-eyed.
Medial strabismus.
So you have an eye
looking over here.
This eye's like that.
Is that OK?
Anyhow, you're wise enough
to know what it means.
But cross-eyed, strabismus.
Let's see.
We want medial deviation of eye.
All right, this
brings us to seven.
What is seven?
Facial.
We've learned about facial
when we had which muscle?
How'd I tell you to tell if
somebody immediately when
they come in the office,
whether their facial nerve is
functioning?
Nobody remembers?
I'm sorry?
Yes, [INAUDIBLE].
Sure, tell them to wrinkle the
forehead, raise the eyebrows.
When you see somebody in the
morning and you can't speak,
you just do that, and they know
you're saying hello, right?
All right, so that's facial.
So we have a motor component,
muscles of facial expression.
Review, review, review.
We have a sensory component.
How many enjoyed
that being in contact
this morning for breakfast?
Tastebuds to the anterior
2/3 of your tongue.
So the sensory
component of facial
is our tastebuds and
anterior 2/3 of tongue.
When you get your
neurology exam,
they'll put some different
flavors on your tongue
and see if you can
taste them, and you
know whether your sensory
is fine for the seventh.
Let's see then, we
have salivary glands.
The submandibular
and submaxillary.
You know exactly where they
are because of their names.
Salivary glands.
Then we have eight.
What is eight?
Pardon?
I hope yours is working now.
That's only half of it.
What's the other half?
Vestibulocochloar nerve.
Vestibular part for balance.
Cochlear part for hearing.
Pure sensory nerve,
like the visual system.
But this is so complex.
We think vision's complex.
Then it gets us up to nine.
What's nine?
Glossopharyngeal, so it
tells you where it is.
What's glosso?
Tongue.
Pharyngeal, you know now,
now you know your pharynx.
So this will be going to muscles
of the pharynx and larynx.
Other muscles are
going there, too.
But we're just doing
a brief introduction.
So how are you going
to test this one?
Tell someone to swallow.
You feel your tongue going back,
right over your oral pharynx,
right?
You should be able to now.
Test, swallow.
What's fun is you
get your friends,
and you go through all of these
and test everybody's cranial
nerves.
10, everybody knows
the vagus by now.
We've mentioned
it so many times.
The vagus, the wanderer.
So it will go to viscera and
thoracic and abdominal cavity.
We took it to the heart.
What was it doing for the heart?
Parasympathetic, what
does parasympathetic
do to the heart?
Slows it down.
So now we're past it.
We're up to 11.
11 is the spinal accessory.
Spinal accessory.
What [INAUDIBLE] does that mean?
For anybody who's
interested in evolution,
it would be fun to
try to figure out
why it has a spinal
component to a cranial nerve.
It's got to come from
the cervical cord,
come up in through
the foramen magnum,
and join the cranial component.
So the spinal
component is coming
from upper cervical
segment of cord.
It joins then with
medulla component.
Will go to muscles in the neck.
What's a major muscle
in the anterior
neck that you've learned?
Sternocleidomastoid.
What's a major muscle at the
posterior aspect of the neck?
Trapezius.
So here's a cranial nerve.
It's a funny nerve.
Coming back down, why
didn't it just go out
to the neck to begin with?
Why did these just
go to the neck?
Who knows?
12.
What's 12?
hypoglossal.
Everybody knows that.
I hope so.
And the hypoglossal
is going where?
Tongue.
Tell someone to
stick out the tongue.
And if they stick
it out and it goes,
you know that they have
disturbed the hypoglossal nerve
on the left side.
There's no muscle there
innervated to get it straight.
So you tell them to
stick out the tongue
and it deviates, it deviates
to the injured side.
So this goes to tongue muscles.
Injury, deviates
to injured side.
Did I ever tell you the
story about the little girl
in Australia who was 12 years
of age and was autistic.
Never communicated
with anybody, did I
tell you that little story?
No, very quickly then.
Because somebody knew her
cranial nerves, a nurse did.
They were at a meeting and
this little girl was there.
Nobody had talked to her.
She hadn't talked
to her back again,
and the nurse said, if you
hear me, stick out your tongue.
She knew her cranial nerves.
She went down the spinal
cord, down the brain
stem as far as she could
with a cranial nerve.
The little girl
stuck out her tongue.
That just opened
the whole thing.
About 10 years later, they
wrote a book together.
So know your cranial nerves.
Very simple, simple
and important.
OK, with that, let's
go to our spinal cord.
Don't sell your spinal cord.
[LAUGHING]
It's so important.
Many people want to
be neurosurgeons,
because they think they're
going to be brain surgeons.
But very little brain
surgery actually takes place,
in case of tumors or accidents.
Spinal cord injuries are common.
That will be the bread
and butter of it.
This is what the neurosurgeons
tell me of tomorrow.
It's operating on
the spinal cord.
So the spinal cord is found
in the vertebral canal
with its meninges,
its coverings.
Those are the CT coverings.
In the embryo, the cord fills
the entire length of the canal.
Entire length of canal.
At birth, how much
does your cord fill?
I always ask that, because
I've seen it on medical boards.
How far does the
cord go at birth?
You think these are trivial.
Almost every statement has
meaning somewhere, right?
So at birth, cord to L3.
In your bodies, adults,
where does the cord go?
Between L1 and L2.
There's a differential
growth between the vertebra
and the cord, and
this is why you
keep getting this cord going
up as the vertebra are growing
rapidly.
So in the adult,
it goes to L1, L2.
So now let's introduce that
term cauda equina, horse's tail.
Did you know you
had a horse's tail?
But it's made up of nerve roots.
Cauda, that's tail.
Equina, horse.
It's made up of nerve roots.
Why does it exist?
If I have my cord and I have my
segments, cervical, thoracic,
lumbar, sacral, and coxagial.
How many cervical nerves?
8.
How many thoracic?
12.
How many lumbar?
5.
How many sacral?
5.
OK, how many cranial
nerves total?
How many?
31 what?
Pairs.
So how many coxagial?
Just checking you.
1 coxagial gives us 31 pairs.
Now we have a
vertebral column, I'm
just giving representative
samples here
to get the idea across of
what causes our cauda equina.
These represent vertebra,
these little boxes.
Because I've got to get my
spinal nerves to go out.
So forth.
So when I'm at the cervical
and thoracic level,
my nerves can come out and just
go out like this through these.
But as I get down further,
these will go down.
Then to get to these,
these will go down
and these will go
down and so forth.
By the time you do
this bilaterally,
you can see where
this horse's tail
has come into this area,
where this is at L1, L2
where the cord has stopped.
But the nerves in
order to go out
through the
intervertebral foramen,
these are nerves in
intervertebral foramen.
they form what's called
the cauda equina.
Does that look
like a tail to you?
I'll show a picture and
you'll agree that it does.
Cauda equina.
So that gives some
basics about the cord.
Let's look at the protective
coverings of the cord,
because they play a
very important role.
We saw some of them and
what they do in the brain.
When you've got your dura
mater forming sinuses,
you saw how it became
modified in the skull.
Let's look at meninges.
Let's do on the cord.
Very simple again, because we
won't be following them out
on the nerves.
We'll just be
getting the basics.
So here is our conus medullaris,
which is the end of the cord.
Conus medullaris.
What level is it?
An L1, L2, right?
That's where it's ending.
L1, L2.
You'll see why that's
very important to know.
You can count up from your
sacral lumbar joint for five.
Then you get where L1 is so
you know where your cord ends.
But now we want to put
on our three layers.
We're going to have pia mater,
arachnoid for spider, and dura
mater.
What did we say pia mater meant?
Gentle mother.
What did we say
dura mater meant?
Harsh mother.
So let's put pia in yellow.
Pia is adherent to the
exterior of the CNS,
whether it's brain
or it's spinal cord.
It is protecting.
We said it formed a
pial glial membrane
if you remember to protect
when you get something sharp
entering your nervous system.
So the pia mater is
adherent to spinal cord.
Then we have the arachnoid.
Leave space between the
pia and the arachnoid.
In pink we've put in
the arachnoid membrane.
It has tribeculae.
You remember tribeculae.
You've seen those in your
lymphatic organs networks
of fibers connecting the
arachnoid to the pia.
These tribeculae, that's what
gives it the name spider,
for spider web.
For arachnoid, spider.
What flows in the
subarachnoid space
that we've created between
the arachnoid and the pia?
Cerebral spinal fluid.
So CSF flows in
subarachnoid space.
That's cerebral spinal fluid.
Do you know how much CSF
you produce each day?
700 cc's.
Think of that.
It's all got to be
reabsorbed every day.
Isn't that phenomenal,
how active it is?
All right, so our
outer membrane now
is going to be the dura mater.
The dura mater is,
you've seen it,
it's heavy, thick, connective
tissue, protective membrane.
So in green we've put
it in our dura mater.
It's thick, bathing cap like.
Thick CT membrane.
What's important here is
that the dura mater continues
on down to sacral two, S2.
What it's formed here,
the cord ended up at L1.
We're down at S2.
We have a sac.
It's called the dural sac.
What's it filled with?
Look at it.
CSF.
Has anybody had a spinal tap?
Oh, heaven forbid, one person.
Two of us.
Spinal taps.
So they have to count down
to be sure they are lower
than L1, L2 to put the needle
in to draw that spinal fluid,
right?
But you see the importance
of knowing that you
won't hit the cord there.
You'll hit the cauda equina,
but they usually move aside
when you go in with the needle.
So this is a level for a spinal
tap Or spinal anesthesia.
They can put the anesthesia
there for delivery for birth
so that you just get the lower
part, not the upper part.
All right, all of
these play a role.
So that's our meninges.
Now let's look at a cross
section of a spinal cord.
I told you I had a
student whose thoracic
area gets tumors more frequently
than the rest of the cord.
Nobody seems to know why.
She had a tumor in
her thoracic cord.
We followed her.
She kept having it removed,
it kept coming back, she
eventually died.
But she sure was a
good example to let
you know that some
parts of the cord
form tumors more
frequently than others.
Why?
Lots to learn.
So we want cross
section of cord.
Oh, let's take our old
familiar part first
so you can see where the
cord segments are derived.
Let's take an embryonic section.
I'm sure you
remember this, right?
We'll do it like this.
What do we call the
center of our cord here?
What is it?
Gracious.
What's the first
part going to be?
Pardon?
Central canal, sure.
Thank you.
Does anybody remember what the
central canal is lined with?
You're gonna get all
of this because you
can get tumors of these cells.
So in green we have our
ependyma lining central canal.
Can you see your
spinal cord back there?
Have you ever tried
to imagine it?
Ever thought of your dural sac?
We call what I've put in
red here the mantle layer.
The mantle layer consists
primarily of nerve cell bodies.
So we call it what?
Gray or white matter?
Gray matter, sure.
It's surrounded then by
the marginal layer, which
is fibers then, nerve fibers.
They're myelinated.
So what do we call this?
White matter.
Fat is white, right?
So these are myelinated fibers.
We'll show pictures of the
myelinated diseases taking away
your white matter.
So now that's how we
see it in the embryo.
But you've been told that you
lose about 50% of your neurons
before you're ever born.
During embryogenesis,
many more neurons
are formed than
you'll ever need.
They're precious,
they're overproduced.
So if we look at a cross
section of the adult cord,
you think you'd
like to find out how
to hang on to all of those
neurons so you don't lose them.
You want all those,
you want choice ones.
So let's put in
now our adult cord,
which we're going to change
our configuration completely.
Now what do we have?
Our central canal is reduced
to a very minor structure,
but it's still present.
There are some
diseases that affect
only the tissue around
the central canal,
so you need to know it.
Central canal.
Then we have our
mantle layer that's
been changed into
what we call horns,
as we see them in a
single cross-section.
So you see how many
nerve cells have
been lost in the spinal cord.
Because originally,
this was all a circle.
But that area which
becomes functional stays.
So this is going to
be our posterior horn
and this will be
our anterior horn.
Sound familiar?
Anterior horn, so what did we
say about anterior horn cells?
They're the largest, right?
135 [INAUDIBLE].
We said we'd see
them eventually.
These are your big
motor cells that
are firing for me to
write on the blackboard.
But now we look at
our marginal layer
out here, all our white matter.
That will be our white matter.
So we see the gray matter
has a specific form.
So does the white matter.
But now, how are we going
to make this functional?
Is our posterior horn going
to be sensory or motor?
Sensory, good for you.
Right.
Because we showed it very
early that if we took this
across here, this was
sensory and this was motor,
your alar and basal plates.
So this will be sensory now.
Our anterior horn will be motor.
We told you the polio virus
attacks these anterior horn
cells.
You get paralyzed with polio.
All right, now
what we want to do
is see how the input comes
and makes use of this sensory.
We'll make a simple sketch then.
Cross section of our cord
again with our horns.
This time, we're going to
introduce our dorsal root
ganglia.
Familiar friend,
dorsal root ganglia.
Group of nerve cell
bodies outside the CNS
over there, a chain of
ganglia alongside the cord.
So now we want to bring
an impulse into the cord.
Let's just pick a reflex.
It's not gonna go to the brain,
it's just gonna go in and out.
So let's have a
pin out here that's
going to prick your finger.
It hurts, pain.
[CHUCKLING]
You are silly sometimes,
but oh, there goes our time.
I do want to take this in.
So the pain is going to go.
Pain usually travels
much slower than this,
but we'll take it in just
because we've got it set up.
Here, what kind of
nerve cell do we
have in a dorsal root ganglia?
What kind of nerve cell is that?
Pseudounipolar, good.
I told you I heard a PhD exam
and a kid didn't know it.
Boy, he got in trouble.
It seems trivial to you, but
when you work in the field,
different viruses
will affect this cell
that won't affect this one.
So you learn them.
You're just getting
your introduction.
So here, my pain
is coming in and it
will go over what's called
the dorsal root here
between the ganglion.
So you can go in and
cut the dorsal root
so that you don't get pain
when you get terminal cancer
and it hurts too much.
So you need to
know these things.
Then we have an interneuron.
What did we say
about interneurons?
What are our three
types of neurons?
Motor, sensory,
and interneurons.
Interneurons, they
connect the two.
Most of the nerve cells in
your central nervous system
are interneurons, connecting
what's coming in and out.
Now we have our
anterior horn cell,
and it's going to come
out and it's motor,
so it's going to come out to
some skeletal muscle fiber.
You'll have an action.
This is your ventral root.
You certainly don't
want to cut that ever.
Let's show slides.
But that gives us a
simple pain in, motor out.
All right, this is
our familiar one.
Here's our forebrain, our
midbrain, and our hindbrain,
right?
Familiar, are you with me
or are you too busy packing?
OK, we had one and two
up here, for forebrain.
Three and four
[INAUDIBLE] and all the
rest from the hindbrain.
Here it shows two coming
out from the forebrain
to form the optic cup,
which will be your retina.
So it's neural origin.
In the next one, and this
shows it within the brain,
these are what we
call optic tracks.
But the optic nerves
will be coming
in from the top of your nose.
Olfactory impulses, these
are your optic nerves.
These are your third nerves.
Your fourth nerve comes
up on the opposite side,
here's the fifth.
Six is here.
Seven and eight
are here, this is
called a pontin cerebello angle,
a frequent place for tumors.
Then you have 9, 10, 11,
and 12 coming out here.
In the next one,
and this just shows
the continuity of the brain, you
can't have a brain transplant.
What's going to happen when
you cut off all this input
from your total body?
You could transplant
pieces, but even those
haven't been too successful.
But you could see the
nerve roots coming out
here and the couda equina here.
In the next one, this is
showing the dorsal root ganglia
in the intervertebral foramen.
Your sensory ganglia.
In the next one, this
shows the coverings.
This is your heavy dura
mater, the arachnoid,
and the pia will
be clear down here.
This is a pia
attachment laterally.
In the next one, this
is the real thing,
but again to show
the cauda equina.
In the next one, this shows
the cord that in the cord,
all of these are ascending
fibers, white fibers, that
have come in, going up
to the brain in red.
The descending on
the opposite side.
So next time,
we're going to fill
in a little bit of the cord
so you can see what transpires
and what can be
cut and what can't
be cut in case of
too much pain or too
much of other sensory
mechanisms are firing.
In the next one, this
shows multiple sclerosis,
a small area of demyelination
in the posterolateral portion
of the cervical [INAUDIBLE].
So here is our gray matter,
here is our white matter.
In this lateral area,
it's demyelinating.
There'll be specific functions.
Look at this, this
is multiple sclerosis
with extensive lesions occupying
practically the entire cross
section of the spinal cord.
Isn't that something?
In the next one, and this is
just to show tumor formation.
We'll put in things
occasionally,
so we'll ask you symptoms
if you have a tumor here.
This is pons underneath,
this is cerebellum.
Got this big tumor growing
here, what might you see?
In the next one,
I think that's it.
