Structure of the Knee Joint (Nursing)

00:01 Now let's finish off the lower limb by talking about the knee, leg and foot.

00:07 Let's start by taking an anterior view of the knee joint.

00:11 Now the knee requires a lot of stability.

00:14 So there's a lot of structures here that just help keep everything in place and in functioning order.

00:21 So we're going to talk about these connective tissue structures.

00:25 The first thing we're going to see is a little pad like structure at the knee joint called the lateral meniscus.

00:33 The meniscus is this sort of halfmoon shaped pad essentially that provides structural support and a little bit of shock absorption as well.

00:42 We have one on the medial side called the medial meniscus.

00:47 And on the edges of the knee joint, we have the lateral collateral ligament and the medial collateral ligament.

00:56 We can't really see it so well in this view, but we can see the anterior cruciate ligament, something you've probably heard of referred to as the ACL.

01:06 There's another one posterior to it, so we see it even less called the posterior cruciate ligament or PCL.

01:14 From a lateral view, we can see some of these other structures a little bit better.

01:19 So from a lateral view, we can see the lateral collateral ligament.

01:24 We also see something we talked about in the hip section called the iliotibial band.

01:30 So we know this is running all the way up towards the pelvis where we had that tensor fascia latae muscle.

01:36 We also have a funny little muscle right here on the posterior surface called the popliteus.

01:42 Popliteal generally refers to this space behind the knee called the popliteal space.

01:47 And it's also why the femoral artery changed it's name to popliteal artery when it passed through the adductor hiatus.

01:54 The popliteus is there to learn it's a little complicated, but it's sort of what we say unlocks the knee during flexion and extension.

02:01 And it provides a little bit of rotation to make sure everything lines up just as it needs to be for flexion and extension.

02:09 We'll swing around to a posterior view.

02:12 And we have the again, lateral meniscus, medial meniscus and lateral collateral ligaments.

02:20 We can also now see, again, the medial collateral ligament and that popliteus muscle.

02:27 We also see, again, the anterior cruciate ligament or ACL and the posterior cruciate ligament or PCL.

02:36 We also see this ligament running off of it from the posterior meniscofemoral ligament providing another series of connections.

02:47 This is a cool one to give you a really good idea of what it looks like from a superior point of view.

02:52 From the superior point of view, you can see how they kind of get the name meniscus, meniscus kind of means like a halfmoon shape.

02:59 And here's the medial meniscus and the lateral meniscus.

03:02 They sort of accentuate the cup like space for the femur to sit at the knee joint.

03:09 We can also really see why the anterior and posterior cruciate ligaments are called this way because they're cruciate like a cross, they're crossing each other like an 'x'.

03:18 We have the anterior cruciate ligament, and the posterior cruciate ligament.

03:23 And again, we have that little bit of additional support by the meniscofemoral ligaments.

03:33 What's happening in the knee joint is very similar to what's happening at the elbow.

03:38 Just like we said, the hip was very analogous to the shoulder while the knees gonna be very analogous to the elbow.

03:44 So generally, we're going to have what we call extension, and flexion, just like we had at the elbow.

03:58 Now, you've probably heard of the ACL, because it's a ligament that can be torn a lot, especially in rapid, forceful twisting motions.

04:07 And especially if one side of the knee joint is fixed while the other is moving.

04:13 So if you have, for example, lateral rotation of the leg, and medial rotation at the thigh, that's going to put a lot of stress and strain on these ligaments that are trying to keep the knee from doing this exact type of motion.

04:28 And so sports like soccer and basketball with a lot of short, abrupt stops and changes of direction will create this stress and strain on the ACL that can result in an ACL tear.