all right all this is dr alsup and our next type of joint that we're going to discuss
are the cartilaginous joints so similar to the fibrous joint video here we will discuss what
cartilaginous joints are made of and then we're going to discuss where we can actually locate them
on the body so cartilaginous joints are joints in which the connective tissue that connects the
bones is cartilage as its name would suggest and these are solid masses or solid blocks of
cartilage which are located right in between the bones and what is actually connecting them
we will see with synovial joints that there is articular or hyaline cartilage associated with the
synovial joints but that is not what is actually connecting the bone so that's the big difference
between that part of cartilage on a synovial joint and the cartilaginous joints which have the solid
mass in between and instead of the three types like we had with the fibrous joints there are
only two categories of cartilaginous joints so let's talk about each one the first one we're
going to discuss is the synchondrosis which has bones that are being connected by a solid sheet
of hyaline cartilage now don't confuse this with a syndesmosis even though they sound pretty similar
but this particular joint has the chondra in the name and we know that that means cartilage is
involved synchondrosis are immovable and many of these are actually what we refer to as temporary
so in the cases of epiphyseal plates these are going to be temporary cartilaginous joints
so remember with epiphyseal plate you're going to have the epiphysis you'll have part of the
diaphysis being connected by this hyaline cartilage referred to as the epiphyseal plate
eventually this cartilage will actually grow and then be replaced by bone and eventually
be completely replaced with bone and then these become those bony joints referred to as synastoses
but not all synchondrosis are temporary uh like in the case of the joint between the top part
of the sternum or the manibrium and the first rib these this is an example this is also an example
of a synchondrosis but it's not temporary it will stay as synchondrosis throughout life
okay so that's the synchondrosis and moving right along let's talk symphyses if you're talking about
multiple and synthesis if you're talking about the singular a synthesis is a little more complex
so the ends of the bones are going to have a layer of hyaline cartilage um but the bones are
actually connected by a broad sometimes flat disc of fibrocartilage so usually the part of
the cartilage that you can see is going to be the fibrocartilage there are some exceptions to
this rule but since most fall within this let's let's go with that definition there
something neat about syntheses is that they are all found along the midline so
like write down that longitudinal axis so you can see here the pubic symphysis which has synthesis
right in its name this is right in the midline the midline would be right in this region here and
we know that because the sacrum is part of that vertebral column which is going down the midline
so it's going to be part of that anterior portion of the pelvic region but in the midline as well as
intervertebral discs which we're looking at a lateral view here so you can't quite tell
that's in the midline but all those bodies of the vertebrae are going to be running down the
midline and the inner vertebral disc is going to be in between those bodies and this is an
example of a synthesis all right so those are the cartilaginous joints let's assess your knowledge
on one of these concepts so question the epiphyseal plate is an example of which
type of cartilaginous joint is it a synthesis b synchondrosis or c synostosis so what do you think
an epiphyseal plate remember is only present in a growing bone between an epiphysis and a diaphysis
and key here it has not been completely replaced with bone like you would have in a synostosis
so synostosis or c is incorrect synthesis isn't correct either because they tend to be
slightly movable they're only located in the midline and epiphyseal plates are not
going to be that so that leaves a synchondrosis as the correct answer and it is i hope
that question felt comfortable to you but if not don't fret you now know this is an
area you need to review a bit more and that is valuable information if you got it correct
then no sweat then you likely don't need to spend quite as much time of your valuable studying
time on something that you're already pretty comfortable with so even when you miss questions
it gives you an idea that that's an area you want to spend a little bit more time studying on
whereas if you get it right without thinking too hard then it's likely something you have down and
you can kind of move on alright so great work keep it up and i will see you in the next video