So now we'll just take a look at some of the ligaments of the knee.
What you need to remember about the ligaments is that you have collateral ligaments, cruciate
ligament and a patella ligament.
We'll start off by looking at the collateral ligaments.
So we've got two collateral ligaments which reinforce the joint on either side.
We've got a medial collateral ligament, which is also referred to as the tibial collateral
and we've got a lateral collateral ligament or a fibular collateral ligament.
We'll take a look at the medial collateral ligament here.
You can see its proximal attachment on the medial epicondyle of the femur and you can
see its distal attachment on the tibia.
It attaches medially on the tibia just a little bit above the insertion points of the sartorius,
gracilis and semitendinosus.
If I just rotate the model around, you can see the tibial collateral ligament and the
three tendons of the sartorius, gracilis and the semitendinosus muscle.
So these three tendons, the tendinous insertion of these three muscles is collectively referred
to as the pes anserinus.
These three insertions could be remembered with the mnemonic sergeant, SGT -- sartorius,
gracilis and semitendinosus.
So laterally, we've got the fibular collateral ligament or lateral collateral ligament.
This attaches on the lateral epicondyle proximally and distally, it attaches onto the lateral
part of the head of the fibula.
So next we've got the cruciate ligaments.
I've just rotated the model around so we're looking posteriorly at the knee.
You can see these two ligaments which cross over each other.
So this is why they're called cruciate ligaments.
The word 'cruciate' comes from the Latin 'crux', which means cross.
You get other words like 'crucify', 'crucifix', which just comes from the Latin cross.
So you can see how these ligaments form this cross.
So this is the posterior cruciate and the anterior cruciate.
It crosses over like this.
You can see their attachment in the intercondylar fossa.
So this ligament here is the posterior cruciate ligament and its proximal attachment is on
the medial wall of this fossa.
So you can see this wall of the fossa.
It's medially on the intercondylar fossa.
And the anterior cruciate ligament has its proximal attachment on the lateral wall of
this intercondylar fossa.
This attaches medially on the lateral condyle and the posterior cruciate ligament attaches
laterally on the medial condyle.
So the posterior cruciate ligament is called 'posterior' because it attaches posteriorly
on the intercondylar region of the tibial plateau.
And if I rotate the model anteriorly, the anterior ligament attaches anteriorly in the
intercondylar region of the tibial plateau.
So I've just isolated the ligament so you can see them a bit more clearly now.
You can see how they cross over at the back here.
The function of the ligaments is to prevent anterior and posterior displacement of the
tibia and the femur.
So you can see because the anterior cruciate ligament attaches anteriorly on the tibia,
it prevents the tibia from sliding forward in this direction.
And because of the attachment of the posterior cruciate ligament, it prevents the tibia from
sliding backwards.
So then we've got this ligament here, the patella ligament.
So this is continuous with this tendon above the quadriceps femoris tendon.
This attaches around the sides of the patella and at the apex of the patella and it attaches
distally to the tibial tuberosity.
So you can see the tuberosity of the tibia.
So we've got a medial collateral, lateral collateral, anterior cruciate, posterior cruciate
and a patella ligament that you need to know about.
So lastly, I'll just talk a little bit about the joint capsule of the knee.
The joint capsule of the knee has a fibrous membrane and a synovial membrane.
So the fibrous membrane is reinforced by various ligaments.
So medially, it's reinforced by the medial collateral ligament.
It blends with fibers of this ligament.
And it also attaches to the medial meniscus, which is why the medial meniscus isn't very
mobile.
Anteriorly, it blends with the patella ligament and attaches to the margins of the patella.
Either side, you've got extensions from these two muscles, the vastus medialis and vastus
lateralis, which contribute fibers to this fibrous joint capsule which are called retinacula.
So that strengthens the capsule anteriorly.
And laterally, we've got the lateral collateral ligament, so the fibular collateral ligament,
but there's a space between this in the joint capsule.
There's a bursa underneath the fibular collateral ligament called the fibular bursa, which separates
it from the joint capsule.
But it is reinforced by this tract of fibers.
The iliotibial tract reinforces the capsule laterally.
And if we rotate around to the back, you can see this ligament, which arches over the back
of the joint capsule.
This is called the oblique popliteal ligament.
This is actually an extension from this tendon, the semimembranosus tendon, which attaches
onto the tibia.
It gives off this ligament called the oblique popliteal ligament, which reinforces the posterior
aspect of the joint capsule.
So lining the fibrous membrane, you've got the synovial membrane.
This attaches to the margins of the articular surfaces and the outer aspects of the menisci.
It's important to note that the cruciate ligaments aren't actually kept contained within the
articular cavity, so the synovial membrane kind of reflects back and it doesn't enclose
the cruciate ligaments.
So the synovial membrane folds in various places to form bursi.
We've got the suprapatella bursa, which as the name suggests is a reflection of the synovial
membrane, which forms a bursa above the patella.
It's supra- meaning 'above'.
So we're looking laterally at the knee here.
You can see the patella bone here.
This is the quadriceps femoris tendon here.
The suprapatella bursa lies in this region just above the patella.
This is a fold of the synovial membrane.
It also folds to form the subpopliteal recess.
This fold lies between the popliteus tendon and the lateral meniscus.
If I just fade away the muscles, we might be able to -- so you can see this muscle here,
this is the popliteus muscle.
And if I rotate it around, you can see the lateral meniscus here.
So this bursa sits under the popliteus tendon between the lateral meniscus.
So another thing to point out is that just underneath the patella ligament, we have a
pad of fat, which is called the infrapatellar fat pad.
This separates the patella from the synovial membrane.
So it sits underneath the patellar ligament and separates the ligament from the synovial
membrane.
So a few other bursi worth mentioning.
You've got this bursa here which sits over the knee cap.
It's called the prepatellar bursa, the subcutaneous prepatellar bursa.
And then you've got this bursa down here, which sits underneath the patellar ligament.
This is called the deep infrapatella bursa.
You've also got one that sits on top of the patellar ligament and that's more superficial.
This is called the superficial infrapatella bursa.
And then you've got loads of other little bursa which sit over the tendons and ligaments,
but I won't go into details with all of those.
So that's the knee joint.