 Hi everybody, Dr. O here. This we're going to cover all the key muscles in the thigh region here, so there's quite a few muscles. I'll go into more detail with the quads and the hamstrings in separate videos, separate short videos, but I want to cover them all here. The psoas major, and you can see the psoas minor up there as well, and the quadratus lumborum have already all been covered, so let's just dive into the actual muscles here in the thigh. So the first group we have is the quadriceps muscles, remember the quadriceps is not the name of a muscle, it's a group of four muscles, and that's going to be the rectus femoris, vastus medialis, vastus lateralis, and vastus intermedius. All four of them are involved in knee extension, and that's kind of odd because using muscles on the front of your body are flexors, but you can see knee extension there in the image. So the rectus femoris is unique, it's, rectus means straight, so run straight up and down the femoral region. Knee extension, but also because it does cross the hip, only when it does, it assists in hip flexion. So the rectus femoris is a knee extender and a hip flexor. The other three quadriceps just extend the knee. So vastus medialis, that's going to be on the inside, very important to keep that strong because it helps keep the patella in the right place when you're running and walking. Very common problem, especially in women because of the larger q-angle due to the wider pelvis, the patella can start to track to the outside and rub on the femur, and it can cause a lot of pain and snapping and popping in the knee, again get that evaluated if you have those issues, but perhaps strengthening the inside of your thigh will help pull that back in place, saw that with countless patients. So that's the vastus medialis and specifically what's called the VMO or vastus medialis oblique fibers right down there at the bottom, I'll circle it for you. So that's the vastus medialis, vastus lateralis on the outside also extends the knee, then you cannot see the vastus intermedius here, I would have to pop the rectus femoris off. So right in the middle, between the vastus medialis and lateralis, you have the vastus intermedius. Okay, sartorius means tailor's knee, longest muscle in your body, imagine you know taking your right ankle and sitting on your left knee, flexion and external rotation of the right hip would allow you to do that, so that's where the name comes from. So flexion and lateral or external rotation, tensor fascialata, its name comes from the fact that it has a really long, really big tendon, it fuses with the tendon of the gluteus maximus to make the IT band or iliotibial band. If that's real tight, especially in runners, it'll cause lateral knee pain. So the function of the tensor fascialata though is flexion and medial or internal rotation of the hip. Then you have your two major adductors, I'll show you all of them in the next slide. Adductor longus and adductor magnus are both involved in hip adduction. I'll come back to that. Grisilis is the most medial muscle there in the thigh and it's involved in a little bit of knee flexion, but also hip adduction. Then you have a little tiny pectinus there is also one of your groin muscles, one of your adductors, hip adduction. Here we've removed all the other muscles and now you can see the three key adductors. Adductor longus is the longest one. Adductor brevis, brief brevity is the shortest one and adductor magnus means huge, so it's the largest one. So the adductor longus and brevis, they're both involved in hip adduction and some hip flexion, bringing your knee up towards your chest. Adductor magnus, though, has so many insertion points. It's involved in hip adduction, but also flexion and extension of the hip. So that's kind of cool. It's a really big muscle down there. All right. Now we're looking at the back of the leg and we have the three gluteus muscles. So remember, if you see a major, expect another muscle called a minor, but in this situation, there's three. So we have a gluteus maximus, which is the biggest one, minimus, which is the smallest one, and medius, which is right in the middle. All right. So the gluteus maximus, it's cut away here, but that your large gluteal buttock muscle, it's a hip extender. So it extends the hip. Gluteus medius and gluteus minimus, they're both hip abductors. So the gluteus medius being the most important one there. If you want to test the strength of the gluteus medius, you have someone stand on one leg. If I lift my, one of my knees up, my right knee up, for example, my pelvis should stay stable. If it tips to one side, it means you have a strong gluteus, or a weak, sorry, gluteus medius. So that's the gluteus maximus, medius and minimus. Then you have the hamstrings, that's not a muscle, it's a group of three muscles, the biceps femoris, semi-membranosis, and the semi-tendinosis. So you can see here, the biceps femoris is called that because it has two heads, a long and a short head. Semi-membranosis and semi-tendinosis, you can see both of them as well. Semi-tendinosis has the longest tendon running down to the knee. That's how I identify it. And then semi-membranosis does have a big, more membranous tendon near the ischial tuberosity, which you can't see it unless you pull the other muscles away. So it's probably easiest just to remember them from lateral to medial or medial lateral. But that's the biceps femoris, semi-membranosis and semi-tendinosis, all involved in flexion of the knee. Okay, that's all the key muscles of the femoral thigh region you need to know. I hope this helps. Have a wonderful day. Be blessed.