Alright Ninja Nerds. In this video,
we're going to talk about the
cross-section of the spinal cord. So
we're actually looking at c3 through c6.
This is actually the body. So this is the
anterior side of the cervical vertebrae.
These are the superior articulating
processes with facets and this is the
actual bi-fid spinous process. So this is
going to be on the posterior side here.
Alright, so here we're looking at a
cross-section of the spine, occurs we're
just taking a little transverse cut and
we're looking at it now. So if you look
here, since this is the anterior side up
here, this is actually the anterior grey
horn of the spinal cord. Now the reason
why they called this the grey horn, it
actually kind of looks like a horn here
but on top of that you have unmyelinated
cell bodies. Here in this anterior or
ventral ray horn. And this is actually
the cell bodies of the somatic nervous
system, so they control your skeletal
muscles. If you look here you have like
your little central commissure and then
a little black hole right there is the
central canal of the spinal cord. That's
where some of the cerebrospinal fluid
runs through. This right here is the
posterior gray horn of the spinal cord.
Okay and it's actually consisting of
cell bodies that pick up peripheral
sensations, we'll talk about that in the
without a sending tracts. Other things we
could talk about the white columns
real quickk this is all the anterior
white column over here and here white
column right there. So they actually
carry specifically for touch and
pressure. All over here is actually going
to be the lateral, all white column over
there's lateral white column they
actually carry pain and temperature
pathways. And then back here is the
dorsal light column and that actually
picks up proprioception and find the
discriminative touch, okay. So now we
talked about the cross section of the
spinal cord, let's actually look at some
of the layers surrounding. This is the
main thing we're going to talk about. So
if you look here, we can see this blue
connective tissue you're clinging right
to the spinal cord. That blue connective
tissue is directly clinging to the
spinal cord is called the Pia mater. Okay
at the Pia mater, then if you look
there's a space right here, sitting right
in here this whole little space, that
space is called the subarachnoid space.
That's where your cerebral spinal fluid
runs through, okay. Then if you look here,
we got to be really, really meticulous
here. If you see this little brown
line going all the way around guys, that
brown line is actually called the
subdural space.
Now on this side, closer to the spinal
cord, there's a blue line this blue layer
here. There's a blue layer on this side
closer to the spinal cord on this side
of that brown line, that blue tissue on
this side is called the arachnoid mater.
So on this side of the brown line, closer
to the spinal cord, lining this part is
the arachnoid mater. And this over here
would be arachnoid mater again. On this
side of the blue, I'm sorry the brown
line again, that brown line right there
is going to be the subdural space. Okay
that's where some certain amounts of
blood vessels and I'm sorry bridging
veins can actually be found. Okay, so
again you have subdural space on this
side of the subdural space, is the
arachnoid mater on this side closer to
the actual bone, this side this is the
actual meningeal layer of the dura mater.
Okay, so inside of the arachnoid mater,
outside is going to be the menigeal
layer of the dura mater. Then you have
this space right here, this space right
here, which contains fat and some blood
vessels is actually going to be called
the epidural space. Okay and then this is
actually going to be the outer
periosteal of the dura mater. So this
is the periosteal layer of the dura mater.
This blue structure here, it's what
clings to the bone okay. So recap, real
quick: Pia mater, subarachnoid space is
the space with the CSF, this blue
connective tissue that's actually going
to be coming in contact with the super
spinal fluid, in the space of this blue
connected tissue on this side of that
Brown Line is the arachnoid mater. That
little brown beige line is the subdural
space. This blue tissue right here, is the
meningeal layer of the dura mater and so,
on the outside of that brown line closer
to the bone, this one right here this is
the epidural space, which is containing
some fat write-ins gonna have some blood
vessels in there and this is the peri
osteo layer of the dura mater. Okay, now
that we covered that, I just want to show
you basically two other structures. I'm
going to turn this actual cross-section
around. Alright Ninja Nerds, so what we're
going to do is, we're going to get a
couple other extra structures on this
cross-section in the anterior side. If
you look here, you see
these arteries. Alright, this is actually
going to be the vertebral arteries and
they're actually running up through this
little space here. Remember that hole,
it's called the transverse foramen. Well
these are the vertebral arteries and they
run right up through that. And they actually
contribute to the posterior part of the
Circle of Willis. They fuse
together and they become the bacilar
artery and they feed into the posterior
part of the Circle of Willis. Over here, you can
actually see the ventral ramus. Over here
is the dorsal ramus. This is actually
going to be the dorsal root ganglion,
which consists of a lot of your unipolar
neurons, right? And over here here you can
actually see some of the fibers that are
coming in to thee specifically, this is
actually going to be the ventral ramus.
So these are the fibers that are coming
out of the anterior gray of the
spinal cord. So these are the somatic
nerves that are coming out of the
specifically the ventral grey horn
they'll go out to supply skeletal
muscles. These are going to be the fibers
back here, these yellow fibers are going
to be the fibers that are taking
sensations from again the periphery,
bringing it through this dorsal root
ganglion, right here which is where a lot
of unipolar neurons are or first order
neurons and stuff. It's going to take it
in through this and into these fibers
here and into the posterior gray horn.
So again,
dorsal root ganglion, this is actually
going to be some of the fibers coming
off, it'll go into what's called the
ventral ramus and some of it can go out
the dorsal ramus. And again, this is the
dorsal root ganglion with unipolar
neurons. And this is going to be the
fibers that are feeding into the dorsal
gray horn of the spinal cord. And again
these are fibers coming from the
ventral gray horn of the spinal cord.
Alright Ninja Nerds, I hope all of this made
sense! I really hope it helped and until
next time.