00:01
Let's begin our
discussion of neck anatomy
by looking at the
bony anatomy of the neck,
which is mostly the
cervical vertebrae,
as well as one special bone
called the hyoid.
00:13
Here we see the cervical vertebrae,
which we number 1 to 7
from superior to inferior.
00:19
We also give the first
two cervical vertebrae,
unique names because of their
unique shape and function.
00:26
C1 is also called atlas
and C2 is also called axis.
00:30
We then have C3, 4, 5, 6.
00:33
And finally C7, which also gets a
special name vertebra prominens
because it projects very
prominently posterior
more than any
of the other vertebra,
and makes it a useful landmark
during physical examination.
00:48
Here's a typical
cervical vertebrae.
00:50
We'll look at the
typical ones first,
and then examine the differences
between these and C1 and C2.
00:58
We see that the body is
somewhat square shaped here.
01:02
The superior surface of
the body is a bit concave
while the inferior
surface is a bit convex.
01:10
Here we have a superior view
where we can see the body
and we see the spinous process
tends to be bifid or split.
01:18
And that's usually in C3 to C6.
01:22
We have the lamina that connects it
to the rest of the vertebral arch
and the pedicle that
connects it to the body.
01:29
Here the vertebral foramen
where the spinal cord travels
is a bit triangular.
01:36
On this lateral view,
we see the inferior and superior
articular process or facet.
01:43
We also see in the
transverse process, an opening,
something we don't see in
the rest of the vertebrae.
01:49
And this is the transverse foramen.
01:53
And this is an important landmark
that is unique
to the cervical vertebrae.
01:57
because these transverse
foramina collectively
are where the
vertebral artery passes through.
02:04
The vertebral artery
is real important artery
because it's going to form
anastomosis in the brain
called the circle of Willis.
02:11
Usually it does skip the C7,
although on some occasions it will
go through that foramen as well.
02:21
Now here are the atypical vertebrae
that look pretty different
from the others.
02:24
Starting with C1 or the atlas.
02:28
We don't really see
much of a body here
instead we have this bump
called the anterior tubercle
on the anterior arch,
which connects to
these lateral masses.
02:38
They do have a transverse
process and a transverse foramen.
02:42
But instead of a
superior articular facet,
we have a facet for
the occipital condyle,
which is a bump on
the occipital bone.
02:51
And then posteriorly we
have a posterior arch
with a posterior tubercle.
02:58
C2 is also pretty atypical.
03:01
Here we see the articular
surface for atlas or C1
upon which it's going to rest.
03:06
And the unique feature here
is this projection called the
dens or sometimes odontoid process.
03:15
And when we put these
two vertebrae together,
we have the atlantoaxial joint.
03:20
And now we can see that C1 or atlas
rotates around this dens
and it allows us
to have this rotating action
as if we were shaking our head no.
03:33
The atlanto-occipital joint,
on the other hand is going to
connect the vertebrae to the skull.
03:40
That's why C1 gets the name atlas.
03:43
It's sort of like the Greek figure
that's holding the globe
on the shoulders.
03:47
Here we see C1. And here are some
condyles on the occipital bone.
03:52
They're going to articulate with it.
03:55
As they come together,
this allows for a flexion, extension
motion between C1 and the skull.
04:03
Much like nodding your head yes.
04:08
Finally,
let's look at the hyoid bone.
04:11
The hyoid is this U shaped bone
that's composed of a body
as well as a greater horn
and a smaller more
anteriorly placed lesser horn
and many important
ligaments and muscles
are going to attach to this bone
and are going to be very important
for the act of swallowing.