Okay let's break down the joint structure classification schemes and as we discussed
previously there's going to be two basic types the first is the solid mass of connective tissue so
the solid masses of connective tissue are actually connecting the bone or binding the bone and
these have specific names sometimes they'll have specific sutural names in terms of ligaments so
the sutural ligaments a big one we'll talk a little bit more about the ones that the distal distal
ends of limb bones as well okay it's discussed in a previous module there going to be two basic
types of joint structure classification schemes the first is going to be where the connective
tissue is actually binding the bone the second you're gonna have that connective tissue capsule
that's going to connect the bone but there'll be space within the capsule region now let's turn our
attentions back to the solid mass of connective tissue there are two examples of those are
two types of those the first is fibrous these are going to connect bone by dense regular or
irregular connective tissue the second is going to be cartilaginous and just as the name would
suggest is going to be composed of cartilage generally it's going to be hyaline cartilage
and then the third type is going to be that connective tissue capsule and we associate those
with synovial joints so let's talk about those fibrous joints in a bit more detail there going
to be three types of fibrous joints the first is sutures and we talked a lot about that when we're
talking about the skull they'll be gomphoses and syndesmosis so sutures are only found in the skull
so only between bones of the skull we think of your frontal your sagittal your lambdoidal but
there'll be sutures anywhere that you have two bones connecting in the skull these are going to
be this really should read and movable sorry for the typo there so that should read immovable and
adults in juveniles is slightly movable so if you think about that soft spot or the fontanel that's
an example of where suture will be in adults so slightly movable obviously in juveniles but
once you reach adulthood that movement should stop now eventually particularly with a really
advanced age you'll have the actual replacement of the ligament with bone and that's referred
to as a synostosis so this is a bony joint where you don't have any connective tissue anymore all
you have left is bone so suture is specific to the skull gomphoses are going to be specific
to your alveolar region or your teeth so this is one of those examples where you don't have
a bone to bone connection you have a tooth and bone connection and it's the perfect example of
a peg and socket joint so you have that peg which is the tooth fitting into the alveolar region of
either the maxilla which is going to be your upper jaw or your mandible which is your lower
jaw so your periodontal ligaments which really keeping that tooth within the bone and the last
type of fibrous joint is a syndesmosis very similar to some of the other terms that we're
going to discuss a little bit later so really pay attention to the terminology here now these are
this is a type of fibrous joint so this is going to be that dense regular or dense irregular
connective tissue what's different is that it's just going to be more substantial generally it's
going to be a little bit wider the best example of syndesmosis are interosseous membranes so recall
your radius and your ulna of the forearm you're gonna have this very distinct connective tissue
that's going to connect the shafts of the two bones you have the same thing in terms of your
lower limb so between the tibia and the fibula you'll have a syndesmosis joint there as well so
those are the three examples of fibrous joints in terms of cartilaginous joints there are two
types there are your primary cartilaginous joints and your secondary cartilaginous joints and these
are actually quite different synchondroses are almost always temporary joints meaning
that they're important in terms of bone growth so once that bone completely replaces the cartilage
then it's a synostosis is a bony joint whereas symphyses are secondary they're there for life
and they're going to be composed of slightly different cartilages as well so as we discuss
those synchondroses are those epiphyseal plates you'll have the replacement of bone
on the diaphysis side and eventually you'll have the complete replacement with bone to become a
synostosis so no movement is allowed at these joints the second type of cartilaginous joints are
symphyses or symphysis and these are really cool these are some of my favorite joints
they're only going to be located in the midline okay so think of the midline of your body this
is only place bull you'll have symphyses these are composed of not only hyaline cartilage but
also you'll have a fibrocartilaginous disc typically right in the middle of the joint
for additional strength of that joint so the two main examples of a symphysis you have your pubic
symphysis which is going to be the anterior portion of your pelvic girdle this can have a
slight bit of movement particularly individuals that are pregnant especially as they get closer
to delivering the baby you'll have a bit more moving in these joints the other main type of
symphysis are actually in these intervertebral discs or those cartilaginous portions between
the bodies of your vertebrae okay and if you think about it you can move your vertebral
column it's because of these joints right here in the midline alright so those are the fibrous and
cartilaginous joints let's talk a little bit about will introduce synovial joints and we'll get into
a bit more detail later on but there's going to be three common structures in all synovial joints
the first is the actual capsule and this is the connective tissue portion of the synovial joint
so this is what's actually binding the bones to one another now note what's different about the
synovial joints from the other two types of joints we were just discussing is these are
going to be on the side of the joints they're not binding right in the middle okay so the binding
is going to be on the edges allowing for the synovial cavity which is the space that's left
because of the not direct articulation between the connective tissue between the bones so this plays
a huge role in terms of why synovial joints are movable if there wasn't that space there
you wouldn't have as much movement capable there the third thing that you're going to find in all
synovial joints is the hyaline cartilage remnant which we refer to as articular cartilage now this
is a unique area it's very important in terms of shock absorption in terms of allowing for movement
to occur smoothly it is avascular so if there's any damage to the articular cartilage then you
can actually get that bone on bone contact that you do not want which can be extremely painful