How to Read a MRI of the Normal Lumbar Spine | Lower-Back | Vail Spine Specialist

Uploaded by neckandback on 17.02.2010

the MRI essentially shows two separate views of the spine
a side view
or a sagittal view
and a bottom up view
called the axial view
on the side view
we literally take a samurai sword and we slice the spine
like a loaf of bread into different sections
and that is represented
by this side view here on the MRI
the bottom-up view
is essentially
axial slices and you can see here
the disc which would be located right here
the center of the canal here
where you see the nerves
and then the two facets on either side in the back
which she is represented on the MRI here
and here
now we're going to examine a
normal lumbar spine
we have two views of the spine
we have this side view here
and we have the bottom-up view here
on the side view
you can see that this side view corresponds to this line in the cut of
where we are cutting the spine
in half literally
so if this arrow or this line is right in the center of the spine this is the
center cut of the side of the spine
move this line anywhere
and we can see cuts for example to the side of the spine here
we can move these
lines to get to the other side of the spine there
so this line that we're looking at
on the right side indicates where the cut is
on the side of the lumbar spine here
to get to the anatomy
this is the spinal cord
the spinal cord ends about right here
and then the spinal cord exits into the cauda equina which are the peripheral
which sit in the center of the canal
we don't see the nerves coming all the way down because they start to exit
if i move this cut over to the side you can actually see the individual nerve roots
on one side
we go back to the center
and then cut on the other side and again you can see the individual nerve roots
on the opposite side
the white material in the center here
is cerebral spinal fluid which is essentially water
on this particular scan
called a T 2 scan
water is white
you can also see the fat in the back here
the fat is also white
mimicking the water
these are the vertebral bodies
that i'm circling here an in-between the vertebral bodies are the discs
the vertebral bodies are named for the five lumbar segments so this is an
L one
L two L three
L four
and L five
the lumbar spine as we talked about before sits on the sacrum
and this is the sacrum
the sacrum has some of the discs
but they're not relevant and this is really one bone
we name the discs
for the vertebra they are sandwiched in between
so for example this is the L five vertebra
and this is the sacrum we call S one so this is the L five s one disc
as we go up this is the L four five disc
the L three four disc
the L two three disc
the L one two disc
and the T 12 L 1 disc as we are now in the thoraic spine
the vertebra themselves
have a
normal grayish hue
which is a little indeterminate
that's what bone looks like which is
filled with osseous structures
and with fat
the edges of the bone on the side you'll see these little black and white areas
these are where the veins of the bone exit called the basi- vertebral veins
and they're normal
if we follow back here
we can see this spinal processes
of the vertebra in the very back
an in-between we see both muscle
and ligament
that hold these vertebral processes together
we can take the side
and come
to the outside where the nerve holes are
and now we can visualize the boney tunnel
called the foramen where the nerve exits
in this case this is the L two nerve
sitting in its white fat which is nature's packing
in the L two three foramen
here is the three four foramen
and this is the L three nerve right here
in it's fat packing
here is the four five foramen
with the L four sitting in it's fat packing and the l five s one foramen
with the l five nerve there
we can conversely go to the opposite side
and see the exact same thing
with the nerve roots exiting out the foramen
if we then go to the top down view here
we can look at
the angulation and cut of the spine
and visualize the spine is what it would look like if you took a samurai
and looked up at the spine from there
we're going to start at the L five S one disc
at this view
this is the dural sac the sac of nerves
all these black dots within this white sea of water
are the nerve roots
and these are the
nerves that hae already exited
out of this sac
these nerves exit like branches on a tree
so this is the five one level
and as we march up
we can get to the four five level
before five level here you can see the normal disc
which has the jelly on the inside the outer plies of the tire on the outside
the back of the disc being either flat or little concave
all of the nerve roots sitting in the
area here of the
dural sac
and then these are the two facets
and back
some people say that facets
looks somewhat like hamburgers with the buns
where you have the meat a little mustard on the inside
and the two buns on the outside these are normal
we can march up then
and go to the next level
and three four and again see the same thing
the jelly filled donut
the outer plies of the tire
the sack of nerves
we get a little higher we can see the actual
forcet joints
and this is a normal level
we can continue to go up and see more here is the basi
vertebral veins
and some of the veins within the vertebral body itself
so when you look at these images these are normal