 Hello, everybody. Today we are here for our last installment of muscle mania. In the first of this three lecture series, we talked about muscle tissue, and then we dealt with axial musculature. And the next one, the one we just did, we talked about the massive and amazing superior limb muscles. And today we're going to finish off the series with a discussion of inferior limb muscles. Now I've organized the inferior limbs, there's 20 muscles that we are going to hold ourselves accountable for. And I've grouped them, I've sorted them for you. I've sorted them into groups based essentially on function, so on the actions that they carry out. There might be a little bit of mushiness in there because we know that any muscle that spans two joints is going to have two different sets of actions on two different joints. So we're going to use that same website that we used for superior limb musculature. But I want to start off, we're going to do the quadriceps group first. This is a group of four muscles. They all are found in the anterior thigh region. And they're a group because they share a distal attachment. So I'm just going to start us off with our little chart here and we'll fill this thing in and you'll see that there is a tremendous amount of similarity in all of them. And so it'll make it easier to look at them when we sort them into this group. Okay, so the major actions of the quadricep group, now they're in the anterior thigh. The biggest action by far is that they extend the leg. What joint do they have to cross if they are going to extend the leg? It means that they're going to have to cross the knee joint and every single one of these guys does that. Not every single one of these guys does the next one, which is flexing the hip. And think about that for a second. What joint would you have to cross it? If you flex the thigh at the hip joint, what joint are you going to have to cross? The hip joint. Okay, we'll get there. So we flex thigh. And there's only one guy who does this and that's the rectus femoris, nobody else does it. So did you see how I did this? Everybody extends the leg, only rectus femoris also flexes the thigh. So that should give you a hint as to what the attachments, where the attachments are for these guys. First of all, I think I already said that they share a distal attachment and that is on the tibial tuberosity. So all of them share that distal attachment. That's why they're a group. So you have these four muscles that all come together and share one tendon and attach to one location. All of the rest of these guys, vastus medialis, vastus lateralis, and vastus intermedius are vastuses. Are vastuses all attached to somewhere on the femur? And I'm sorry, but we're just, I mean, it's somewhere on the shaft of the femur and there are specific locations, but when I think of them, I think of them kind of smeared to the shaft of the femur and I'm fine with that. So let's just say they attach to the femur and you can see how, if we're attached to the femur, we cross the knee joint and then attach to the tibial tuberosity, the tibial tuberosity, then yeah, we're going to have some total leg extension happening at that with those muscles. So this femoris, if it's able to flex the thigh, what does that tell you? It tells you that we have to attach somewhere on the pelvis and in fact, I'm going to give you the name. This wasn't a bone bump that we had in our list, but it's going to be in the future. So take a deep breath and the attachment is the anterior inferior iliac, oops, iliac spine. There was a bone bump that we did learn on the ilium and that was the anterior superior iliac spine. So hopefully anterior inferior iliac spine isn't crazy. Like that's, it's just, it's on the same line of the iliac spine, it's just inferior to the superior one and the superior anterior superior iliac spine is the one that you can actually palpate. It's the hip bone. If you're all volleyball players out there, when you are going for an awesome save and you smash yourself all over the floor and you hit your hip bones, that you're actually whacking your anterior superior iliac spine. Ouch. Okay, let's take a look at these guys. This is okay. I think, oh no. Yeah, this is, this is all right. Here is rectus femoris. Rectus means straight. So you can see that this is a super straight little muscle here and you can see that it's attached to the anterior inferior iliac spine. This is anterior superior iliac spine right here. So that's rectus femoris and you can see where it comes down. The patella is actually embedded in that ligament that then, or the tendon, that then attaches to the tibial tuberosity. All right, I'm going to make this go a little bit like what's the word? We're going to zoom. Come on now. Really? Oh, geez. Oh, geez. There. No. What's the scoop? There. Whatever. That's fine with me. Okay, so we have to go deep. Rectus femoris is superficial and so we're going to have to get it to come off and we just did. Look, then we have vastus lateralis and vastus medialis and you can actually see them. If you're looking, you have rectus femoris and then to the lateral and medial sides, you can see vastus lateralis and vastus medialis and you can palpate those guys as well. And then if you go even deeper, you're going to find vastus intermedius, which is deep to vastus lateralis. Do you see that? Vastus intermedius truly is like a total smear action on the femur. All right, that's our quadriceps group. The next one we're going to do is we're going to look at a group of three other thigh movers that kind of don't fit into a nice little category rather than that they're not in the quadriceps group. Okay, I can figure out how to turn this off, watch.