Hello anatomy friends this is Dr. Alsup and we spent quite a bit of time talking about
the different structures of the vertebrae and now we're going to talk about the main joints that
you'll find associated with the vertebral column and there are a lot of different types of joints
we're not going to get into some of the smaller ones we're mainly going to focus in on these
intervertebral discs and so we'll talk about where these are located what's going to make up an
intervertebral disc and then we'll talk a little bit about herniations of the disc
all right so intervertebral discs are often referred to as the IV
discs sometimes you could hear them even referred to as joints of the vertebral bodies
because these will be located between bodies of the vertebrae you can see it right here
these are actually examples of symphyses if you recall our conversations of symphyses these were
are a type of cartilaginous joint recall that all symphyses are going to be located
in the midline so those vertebral bodies certainly will fit into that as well
and you will have an intervertebral disc between each vertebral body so each kind of set of
neighboring vertebral bodies except between C1 and C2 which makes sense because you have that dens
that is going to kind of move into that region so there's really not room for a vertebral body there
and you will not have any intervertebral discs between the non-movable or fused
vertebrae of the sacrum and the coccyx but you will have a intervertebral disc between L5
and S1 so between the last lumbar vertebrae and the sacrum and the size of the intervertebral
disc will vary in different regions the discs will get larger the more inferior you get so
we are looking kind of at a lumbar region here so you can see it can actually get quite large
the two components of the intervertebral discs are going to be the outer anulus fibrosis
this is usually the largest component it is going to be composed of fibrocartilage
and an important thing to note so if we look at this is the posterior portion because
there's a spinous process and this is anterior because this is the body this posterior portion
of the anulus fibrosis is going to be a little bit weaker than what you have in the other regions
and that weakness that inherent weakness can have some implications in terms in terms of herniations
in the middle you will have the nucleus pulposus and this is kind of a semi-fluid mucoid kind of
region it will get smaller with age some of it can convert to fibrocartilage with age but you
typically will have some nucleus pulposus even into advanced age and when you've if you've ever
heard of the term slipped disc this is this is kind of the the colloquial term for herniation
of the nucleus pulposus and what will happen is that that inner portion that nucleus pulposus
will herniate or escape where it typically is held and it will do so because there is some type of
damage or weakening associated with the anulus fibrosis and any of those other ligaments that
are going to be in this region and so if you have a slipped disc particular these typically will occur
or be directed posterolaterally so you can see in this one it is this would be posterior
again this would be anterior so you can see it escaping or kind of moving posterolaterally
this as you can see here this is the spinal cord and this is a spinal nerve so
if you have herniation of the nucleus pulposus it could feasibly compress on the spinal cord
but more likely it's going to compress on the spinal nerve right around that intervertebral
foramina region so where it's kind of exiting through the vertebral through the vertebral column
so you could have pinching of the nerve or compression of the nerve due to the herniation
and the most typical pla placement or the most typical place for slip discs are
between the intervertebral disc associated with between L4 and L5 or between L5 and S1
because that lumbar region really bears much of the weight of the body
and you also have a lot of movement actually associated with the lumbar region
so it just most often will occur here because of those those factors
all right so this we just talked about but it's an important concept so herniation
can happen at any intervertebral disc so that's an important thing to note you can have herniations
at any level or at any location of where there's an intervertebral disc but it's most common with
intervertebral joints at which vertebral levels is it the cervical region the lumbar region or
the thoracic region so really the key here is where is it most common and hopefully you
recall our discussion just a moment ago that it is the lumbar region due to the fact that there's
a lot of weight in this region there's a lot of weight of the body occurring here there's also
increased movement of the lumbar region so think try and try to move your lumbar region and you
can actually have quite a bit of movement there so that can lead to kind of a weakening in that area
cervical it certainly can happen there herniations are not they're not all that uncommon in
the cervical region this actually be kind of the second place that they would most likely occur
thoracic is a bit more a bit less typical but lumbar is by far going to be the most common site
okay so that should wrap us up in terms of the intervertebral discs of the vertebral column
remember those are between the bodies and they will increase with in size the more inferior you
get thank you for your time and attention here as always please feel free to reach out to me with
any questions and let's move on to the muscles of the neck and the back thanks for your time bye