hello anatomy friends this is dr alsup and you cannot have a back and spinal cord session
without talking about the vertebrae and so we're going to talk through some structures
that are going to be common to almost all of the vertebrae and we're looking at a superior
view of the three movable types of vertebrae or examples of each one this will be the cervical
this will be the thoracic and this will be the lumbar
we talked a little bit in the learning objective videos as to
how to determine which one is which right now we're going to focus on just
some of those structures that you have in all of them so the large anterior bodies are going to be
just as you would think one of the largest structures associated with the vertebrae
you can see how very large they are in the lumbar vertebrae they look almost heart-shaped
in the thoracic vertebrae or in many of the thoracic vertebrae and they're they're going
to be relatively large for the cervical as well even though overall these are smaller vertebrae
and then extending from the the body you'll have these short extensions little feet as we call the
pedicles you can see a bit of it right in this region here so the pedicles are going to be part
of that vertebral arch it is going to meet with the laminae and you can see the laminae are these
flat plates of bone a little bit more com complex when you're looking at the lumbar region but these
are going to be more so if the body is anterior the laminae are going to be more posteriorly
facing the transverse processes are going to extend laterally as part of that vertebral arch
you can see that they vary very quite a bit in terms of what they look like depending on
region so you can see how short they are when you're talking about the cervical vertebrae and
in some of the cervical vertebrae they could be bifid meaning that they're kind of separated into
two processes here is a thoracic vertebrae transverse process and you can see they are
they extend quite a bit laterally in the lumbar region but are a little bit thinner the spinous
processes are going to be our most posteriorly projecting processes and these are the ones that
if you kind of run your hand down the midline of your back you are feeling those spinous processes
because that's about as posterior as you can get right and you can see that there's going to be
differences between the types of vertebrae but you can see in terms of the cervical again you could
have an example of a bifid process also associated with the spinous process and then of course all of
these vertebrae are going to have a vertebral foramen and if you join all these vertebral
foramina together throughout the vertebral column you get the vertebral canal where you have
the spinal cord the roots of the spinal nerves meninges and epidural fats sitting in that region
now looking at a lateral view you can get a better view of the definitely the
vertebral notches really you can only see these vertebral notches from these lateral views
and we can also see some of these other structures that we're going to get to so articular processes
are going to have projections for which you're going to have those facet joints and so you'll
have a superior articular process articulating with an inferior articular process of another
vertebrae so you can see a superior one right here in terms of the articular process and
an inferior one and you can kind of see them extending throughout these regions
the notches like i said you're only going to see on a lateral view and you can see
very nicely on the lumbar vertebrae and i meant to say that we're looking at a cervical
a thoracic in a lumbar again so kind of from the superior down to inferior
so if we're looking at this lumbar vertebrae you have a really nice example of a superior
vertebral notch and an inferior vertebral notch and so in this lateral view you have and
typically these transverse processes particular excuse me the spinous processes particularly in
the thoracic vertebrae are going to be sloping downwards they all have a little bit of a slope
and so that that's how you can kind of get an idea of which one's going to be inferior and
which one's going to be superior and then if you put the vertebral notches together
for neighboring vertebrae you will have these intervertebral foramina and you can see them
throughout the entirety of the vertebral column and these are going to allow for the spinal nerves
or the trunks of the spinal nerves and those primary rami to leave the vertebral column
all right moving to the immovable vertebrae we will reach the sacrum the sacrum is going to
articulate with obviously l5 at about this region here and then you will have it articulating with
the hip bones for your sacroiliac joints we're looking at an anterior view here and a posterior
view so right off the bat you can see this posterior view looks a bit more complex you have
very small remnants of the spinous processes in some of these regions and if you get
down to about the level of s4 or s5 particularly s5 you will see that you do not even have a lamina
or a spinous process so you have a complete absence of those two structures and that region
right here is referred to as the sacral hiatus and that sacral hiatus will lead into the sacral canal
and here's the beginning of the sacral canal where you have that nervous tissue kind of
passing through similar to the the vertebral canal so it's just an extension of that vertebral canal
the sacral hiatus is not a pathology this is something that you will see in most individuals
you'll have these very prominent sacral foramina so if you're looking at the anterior side these
would be anterior sacral foramina and then if you're looking at the posterior side
with those little remnants of the spinous processes then you know you're looking at
the posterior cycle foramina obviously they are going to be continuous with one another
there are typically four pairs of these sacral foramina and this will allow the
exit of the ventral and dorsal primary rami of those sacral from the sacral levels
the coccyx is going to be also an immovable portion of the vertebral column it is typically
this is not going to be a weight-bearing portion of the vertebral column and this portion right
here is going to be the coccyx oops sorry i cut it off a little bit there and then you can see a bit
of it down in this region here so that inferior most portion of the vertebral column it's going
to be the fusion of four or approximately four rudimentary coccygeal vertebrae that number can
be variable and coccyg the coccygeal vertebrae number one may remain separate from the rest of
the coccyx as you can see that is the case here with this individual these last three
or the most inferior three coccygeal vertebrae typically fuse during around the middle ages
of your life and these are definitely the most rudimentary of the vertebrae in terms of size
all right let's talk about a few of the special vertebrae the ones that are very unique in terms
of presentation and or may have some specific clinical significance we are looking at the c1 or
atlas here this is c2 or the axis and then this is the articulation between the two bones here
c1 is the bone that is going to articulate with the skull or with the cranium
with these large processes that will articulate with the occipital condyles
of the cranium and this bone also is very distinctly ring shaped as you can see here
and it will have no spinous process and no body so that is pretty unique in terms of the vertebrae
and i said this is c1 but also called atlas think of atlas of greek mythology holding the world or
bearing the weight of the world on his shoulders well c1 is bearing the weight of the skull
see one um carrying that skull or the cranium is going to rotate on c2 to allow that shaking
you get when you shake your head no and you can see here that dens is going to
superiorly project so this dens right here is that projection you can see right here on c2
it's going to project superiorly from the body of c2 and it will serve as that
pivot about which the head rotation occurs or that c1 rotation occurs that carries the head
c7 often referred to as the vertebra prominence and you can kind of get here i can count from
bodies one two three four five six seven look at what's going on here you have this very prominent
spinous process associated with c7 it's typically the most prominent spinous process even though
t1 and sometimes c6 can have very close in terms of prominence of the spinous process
it typically is usually that most superior process that is visible through the skin
even visible sometimes without flexing the vertebral column and so you can use
that you can see it first of all and get an idea of about which vertebral level
you're at just by looking at an individual and oftentimes by if you need to palpate as well
and that can help in terms of if you're having to enter a needle into that region or do some type
of surgery you have an idea of about where you're at there and last but not least i can't not talk
about transverse foramina because i think they are so cool um cervical vertebrae have this very
unique foramen so not that vertebral foramen which is right in the middle here
but these two foramen that are associated with the transverse process of the cervical vertebrae
and you only have transverse foramina in cervical vertebrae and that's very unique
if you're ever trying to identify one even if you're looking if i go back to c1 and c2 you
can't see it all that well in c2 but they're there so you know you're looking at a cervical vertebra
and this allows for the vertebral artery which is a branch of the subclavian artery which is all
the way in the root of the neck it allows for that vertebral artery to ascend up through the neck all
the way up to within the skull and it's going to be one of the two dominant suppliers of our blood
to the brain so a very important route by which that artery is protected in its way up to be able
to supply that all-important brain all right excellent so that was a lot of vertebrae fun
there is a lot to kind of look at in terms of this and as you're reviewing
you know take time really looking at these vertebrae and trying to id on your own and if
you work through this and you find areas that you need a bit more clarification please please always
feel free to reach out thank you for your time and attention here and have a great rest of your day