So in our last mini lecture we were talking about classifying joints. We classified them according to their structure
They were either fibrous cartilaginous or synovial and we talked about
Classifying them according to their function. They were either sent our throttle and three automatic or die erotic so today
we're going to narrow in and we're going to talk about the synovial joint in particular and
Really what we want to be able to do with this is identify the anatomical structures that are within the joint
So why do we care about the synovial joint more than we do the other joints well?
One Remember, it's a diuretic joint any of these
Joints over here. These are dire. Throt acquit means. They move a lot and because they move a lot
They're more susceptible to injury. So isn't it then
Reasonable to learn a little bit more about the anatomical features of these joints
So that we can understand injuries better
so first of all let's look at the
Joint capsule so here you have two different bones right, maybe this is the femur and the tibia
maybe this is the humerus and the oma but
We're looking at two bones that are articulating their joining together
So the first thing that we see that protects these bones is their articular cartilage?
And we've talked about articular cartilage before, so this is a type of hyaline cartilage
So you have this thin layer of cartilage on top of the bones that protect the bones from?
Being worn down, so this is going to help reduce friction
so some injuries will happen when
This articular cartilage begins to deteriorate and think about that if there's no
Protection here that means you have two bones on top of [bones]
Rubbing together and they're going to start to break down that hole
piphus asst of the bone and so then you might have arthritis the
synovial
Membrane then so these are synovial joints so here on in the purple you have the synovial membrane
Connecting those two bones together, so this is pretty continuous with the periosteum
You have this lining and then that connective tissue is going to itself produce fluid so inside here
On in this blue area the synovial cavity you're going to have synovial fluid and synovial fluid
Again like any other fluid is going to be a lubricant so that's going to help reduce friction between bumps
Continuing on we have ligaments and tendons, so it's important. We know the difference between the two so ligaments
You know hold bones to bones, so you're going to have
reinforcement ligaments
And the various sides of the joint so if you think about the knee joint we've heard of ACl's
That's the most common. I think injury that we hear in the knee the
Anterior Cruciate ligament where would that be found in front of the joint right so you?
also
have a posterior ligament a PCL you have an MCL and an LCL, so
It's going to surround all four sides of [that] joint so those are
Reinforcement ligaments, they're trying to keep the bones moving as they're moving they're going to try to contain them within that space
Then you have tendons tendons connect muscles to bone
How do we produce movement by muscles pulling on bone so movement wouldn't be produced if the tendon wasn't?
Attaching the muscle to the bone the bones don't move on their own they [have] an outside force
So in this picture here is a muscle and usually you're going to see [that] with these
Striated lines to demonstrate muscles and the muscle, then is attached to the bone in some way
Tendon sometimes it's like a sheet of connective tissue. It's called Faccia, but in this case
we're using a tendon this could be the knee in which case you have the patellar tendon connected to the Tibia and
then
and
then you have your ligament over here, so the this is going bone to Bone whereas the tendon is going muscle, Tuba and
then we have
The synovial cavity that I kind of mentioned already. That's the Joint cavity
It's the space between the two bones
So if things are going to move they have to have space to move right
So that's the purpose of the joint cavity giving them a little mobility so that's where you're going to [find] your synovial fluid
Another fluid you'll find in Joints are contained within Little sacs called VS
So this is [a] fluid-filled Sac again that's going to help with um cushioning
So it's kind of like a liquid Pad
Let's say um you might have heard of water on the knee that's another injury. That would be when that Bursa
fills up with fluids
So maybe it's lymphatic fluid plasma that is leaked from the bloodstream trying to heal an injury and so it accumulates in that versa
So there you have it. That's the basics of the synovial joint anatomy. We talked about ligaments holding bones to bones we talked about
attendance holding muscles to bones we talked about the articular cartilage the
Synovial Membrane which Produces synovial fluid within the Joint cavity, so you should
Feel better that you now understand the joints of your appendages