This is a tutorial on the knee joint.
The knee joint is the largest synovial joint in the body and it's these articulations between
the femur and the tibia and also between the patella and the femur.
So it's a hinge joint and the main movements you get at this joint are flexion and extension.
So in this position here, which we're looking at the model, this is in the fully extended
position, so you get flexion and extension.
Flexion is back this way and extension is up this way.
You also get a little bit of rotation at this joint.
So when the joint is flexed, so when the femur is pulled up this way, you get a little bit
of medial and lateral rotation.
In full extension, which is what we're looking at here (so in a standing position), the femur
medially rotates on the tibia and the joint is locked into position and you've got ligaments
on either side, the collateral ligaments, which tighten to lock this joint into position
so it's stable in this position.
And then to unlock the joint, the femur is laterally rotated on the tibia.
So first, we'll just take a look at the articular surfaces of this joint.
So the articular surfaces are covered by hyaline cartilage and you've got the femoral condyles
-- I'll just rotate it back.
You've got these two femoral condyles articulating with the tibial condyles of the tibia, so
the superior aspect of the tibial condyles.
So we've got a medial and a lateral femoral condyle here.
We've got the same for the tibia.
So we've got medial and lateral tibial condyles.
The articular surface of the tibial condyle is the superior surface, which I'll show you
in a moment.
So the two femoral condyles here are separated by this region, which sits between them.
This is the intercondylar fossa.
So this fossa, this intercondylar fossa is the area where the anterior and posterior
cruciate ligaments have that proximal attachment.
So I'll come on to talk about that in a moment.
And just above the condyles, you've got epicondyles.
So this is the site of proximal attachment for the collateral ligaments, the medial and
lateral collateral ligaments or the tibial and fibular collateral ligaments.
So the epicondyles are actually not articular.
You've got these epicondyles here where the collateral ligaments attach.
And then anteriorly if I just remove the patella bone, you've got this little sort of groove
in the femur where the patella articulates.
We'll just take a look at the tibia as well.
We'll look at the proximal tibia.
You've got the tibial condyles which articulate with the femoral condyles.
So you've got a medial tibial condyle and a lateral tibial condyle.
I'll just remove the other bones so we can look at the superior aspect of the tibial
condyle.
I'm just going to rotate the model so we're looking at the superior aspect.
You can see the sort of faded fibula, so this side is lateral and this side is medial and
we've got anterior up here and posterior down here.
So I'll just fade out those bones now and we'll look at the superior surface of this
bone.
So this is the articular surface of the tibial condyles.
We're looking at the superior surface of the medial condyle.
Here's the superior surface of the lateral tibial condyle.
In between these two condyles, you've got these regions, the intercondylar region.
This region is important because you get the menisci of the knee joint attaching in this
region and also the anterior and posterior cruciate ligaments attaching in this region.
I'll show you that in this tutorial.
So this whole region, this whole superior surface is referred to as the tibial plateau.
So it consists of the articular surfaces of the tibial condyles and this intercondylar
region.
So that's the tibial plateau.
So if I just rotate the model around a little bit, you can see that there's eminence, this
protuberance of bone.
This is the intercondylar eminence.
Laterally, we've got the lateral intercondylar tubercle and medially, we've got the medial
intercondylar tubercle.
So just while we're looking at this view, I'll just talk a little bit about the menisci.
So these are fibrocartilaginous structures which sit on either side and they're crescent-shaped.
So the menisci are also called semilunar cartilages because of their half moon shape.
They function really to act as shock absorbers and they accommodate changes in the movements
of the bones at this joint.
So I'll just switch over to another diagram.
We're looking at the exact same view.
We're looking superiorly at the tibia, the tibial plateau.
This is anterior up here, posterior down this side.
You can see these crescent-shaped menisci.
You've got a medial meniscus and a lateral meniscus.
You can see how they attach in this central intercondylar region.
You've also got the anterior cruciate and posterior cruciate ligaments attaching in
this intercondylar region.
You can see anteriorly that there's this ligaments which connects the two menisci.
This is called the transverse ligament.
So some other things about the medial meniscus.
It's actually attached medially to the tibial collateral ligament or sort of blended with
the fibers of the tibial collateral ligament and also to the capsule of the joint of the
knee.
So it's actually not very mobile because of these attachments, whereas the lateral meniscus
doesn't have these attachments to the joint capsule, so it's a lot more mobile.