now we study the muscles of the hip joint and knee joint but before we start let me make sure I've made something clear right now am i flexing and extending my wrist or my hand well both really the joint is the wrist but what moves is my hand so you could say either flexing my wrist or I'm flexing my hand same with the elbow am i flexing and extending my elbow oh or am i flexing and extending my forearm typically we talk about the joint so I would most likely say I'm flexing and extending my elbow joint but you could say forearm same thing here with the hip joint I can't show you that but if you were to flex and extend your hip joint what you would be moving would be your entire lower limb now it's kind of better to say hip joint because you would say well I'm flexing and extending my lower limb but I'm making sure my knee stays locked because hip joint is different from the knee joint I can get kind of confusing but it is the same thing so let's move this hip joint meaning let's move the thigh or the entire lower limb and we'll look at these three muscles first gluteus maximus the world famous luteus bootie is muscle which here has been cut because otherwise we would be hiding a lot of the deeper muscles you can see it intact on this other image very large broad muscle in your butt now let's point out there's also a gluteus medius which has also been cut in one of these images but you can see intact on the other image so there's the maximus gluteus the biggest one and then there's gluteus medius the middle one and those are the only two you're responsible for here's a red arrow indicating that I thought you might want to know if there's the big one in the medium one that there's also the little one yeah even though you don't have to learn it I just pointed it out there gluteus minimus is the third and final gluteus muscle so let's look at the OIA s for the gluteus maximus and medius the origin of the Maximus is the sacrum and a portion of the iliac crest it will insert on the gluteal tuberosity sometimes it's that easy remember the deltoid inserting on the deltoid tuberosity here gluteus maximus inserts on the gluteal tuberosity but don't forget the femurs have these big structures that are unique to them called trochanter so we want to make sure we use those two so the other two muscles here gluteus medius and piriformis will insert on the greater trochanter their origins are the iliac crest which we can verify here and the sacrum here's our piriformis meaning high shaped pizza slice shaped and insert somewhere on the sacrum now we can see a few other muscles here like the gracilis and adductor Magnus and so on but those are better seen in the next slide but we should point out here that we have a muscle called quadratus femoris quad is like a quadrangle like a rectangle so this is the rectangular muscle of the femur quadratus femoris you don't need to know anything about it just be able to identify it we can also see here on the very lateral edge of the leg a muscle called the tensor fasciae latae and inferior to that the iliotibial band or the IT band or IT track so what the tensor fasciae latae does is it puts a lot of tension on some fashio and fashio is one way of saying some deep connective tissue which is what the IT band is a bunch of connective tissue and so that that IT band can be tense or relaxed to support certain movements of the lower leg and the muscle responsible for that tension and relaxation of the IT band is the tensor fasciae latae you see it with a couple different spellings here so I of the e in parentheses okay let's look at some of the other muscles that move the hip joint we can see them better with this image where many of the superficial muscles are taken away the iliacus has its origin on the iliac fossa remember a fossa is a dish like shape on a bone so the iliacus fills up much of the iliac fossa and where's it going to insert well what's the big unique structures on the femur the trochanter we already used the greater trochanter but we still have that lesser trochanter so we'll slap several muscles on there to insert on their fault this iliacus muscle and the psoas major will insert on the lesser trochanter the psoas major has a very different origin than the iliacus you can see it way up here attaching to the transverse processes of the lumbar vertebrae now these two muscles iliacus and so s major as they head inferior they will fuse and so they're sometimes referred to as the iliopsoas just kind of mashing together those two names to make one name called the iliopsoas the function of these is to flex the hip and hopefully for some of these muscles maybe not all but for some of these muscles it will be relatively intuitive what they do meaning these muscles are kind of starting out at the side and the back of your body and then they attach towards the front of your femur so if you were to take your fingers right now and go down and pinch the front of your femur and pull them towards the back inside of your body your femur should flex your hip joint should flex so flex hip is the function of these muscles they're just pulling from the back pulling that femur up gracilis and adductor magnus are both responsible for hip adduction and if we find those muscles you'll see gracilis is here and adductor Magnus is a very broad muscle it's hidden partially behind some other muscles it is a very large muscle in the inner thigh so those two muscles hopefully their action also makes sense if you imagine these muscle fibers shortening and contracting it will pull your leg towards the midline that's adduction Crystalis and adductor Magnus have their origin on the inferior ramus of the pubic bone and the gracilis inserts on the medial condyle of the tibia adductor Magnus inserts on Linea aspera remember that's this aspiring line or what really translates to the rough line down the back of the femur I put a couple other muscles here because you just learned about adductor Magnus the big adductor muscle we should also make sure we mentioned adductor longus the long adductor that's on your list but what's not on your list is adductor brevis again you don't need to know this for the course but if you have the big adductor and the long inductor maybe it's useful to know there's another one the short adductor adductor brevis okay now we can finish off by moving the knee joint let's start with the Sartorius it's not exactly s-shaped but there's a definite curve to the Sartorius it really starts up on the anterior superior iliac spine right up here and it curves over the front of the leg and inserts down on the tibial tuberosity you know that bump on the very top of your shin region and just like any muscle that has kind of some curvature to it or is very wide these muscles tend to be able to cause a lot of different action so the Sartorius can flex the hip because it starts way up here on the hip bone so it can act on the hip joint but it can also flex the knee because the Sartorius crosses that joint too I mean it's the longest muscle in your body so it can affect more than one joint in this case so it can flex the hip it can flex the knee and it can laterally rotate the hip meaning since this is a right leg it can spin right leg laterally the last four muscles here are called the quads or more specifically they're called the quadriceps or quadriceps femoris the four headed muscle of the femur so first is rectus femoris to find actually any muscles of the quads here's what I humbly suggest you you find the patella because I know you can do that run your finger up from the patella straight up and that will make sure you found the rectus femoris successfully now when you're all fancy you might be able to do this without the patella you just see a cadaver weightlifter patient whatever you can find rectus femoris but for now find that patella go superiorly find the rectus femoris that way now if you go medially you'll find a big muscle called vastus medialis the vast you know the large wide muscle in the medial region and then go back direct is for Morris and then this time look laterally and you'll find the fastest lateralis the vast you know the big wide muscle on the lateral side of the thigh and then finally if you cut through the quadriceps tendon and you lift up rectus femoris or what we tend to call reflect if you reflect that muscle by pivoting it out of the way you'll find the final muscle of the quads vastus intermedius hidden below rectus femoris so these muscles have different origins rectus femoris on the anterior inferior iliac spine the vastus muscles we simplify to just say they're on the femur with vastus medialis specifically having its origin on the Linea aspera they all insert on the same place the tibial tuberosity that bump on the proximal anterior surface of the tibia same place that Sartorius is coming down to attach to and they can both flex the hip and extend the knee because the rectus femoris muscle at least starts way up on the hip bone so it can cross multiple joints so it can act both on the hip and the knee just like the Sartorius can looking on the back of the leg to move that knee joint back here you may know are your hamstrings so let's look at specifically where and what those are there are four muscles that make up the hamstrings biceps femoris has both the short head and a long head and then there's the semitendinosus and semimembranosus so looking at the back of the thigh one thing you want to do is find these four muscles we're talking about so there's one here there's one here one here and one here here's how I approach these first I look at the back of the thigh and I kind of draw myself a line down the back of the thigh because usually you can find pretty easily this like indentation that separates the medial and lateral back of the thigh now I know that on one side of my hamstrings are these biceps femoris muscles and on the other side are the semi member noses semi tendonosis muscles but I can't remember which is which so here's mama my way of remembering I say that the muscles with a lot of MS meaning the semi mama member enosis and the semi mum of my tendonosis those are on the mum um um medial side in this image reveals here and the other ones are on the lateral side so once you do that you say okay on the medial side or the semi tendonosis and semimembranosus well semi tendinosis should be roughly half tendon right that's what semi tendon means it's not really but this is all semi tendinosis is that half tendon no but it does have a pretty long tendon down at the bottom here semi membra gnosis is partially hidden it's deep to semi tendinosis so you can see I put the arrow in two different places trying to make sure you realize semi remember gnosis is wide and tendinosis and a bisects it then the biceps muscles are on the other side the long head is very long when compared to the short head which you just see a little bit of so that's how I locate these muscles the origin of the short head of biceps femoris is on the Linea aspera a very popular origin site for muscles of both the anterior and posterior thigh inserts on the lateral condyle of the tibia because of course it is found very lateral and like the rest of the hamstrings it will extend the hip and flex the knee what did the quads do again flex the hip extend the knee so we're doing the opposite not flex hip extend knee now we're extend hip flex knee in other words the quadriceps and the hamstrings have the opposite actions on the hip and the knee joints finishing off here all these other muscles of the hamstrings have their origin on the ischial tuberosity and have a couple of possible insertion sites either on the lateral condyle or medial condyle now before we jump into our last video of appendicular muscles take a look at something like this can you name any of these muscles I'll wait I won't wait I'm gonna give you a suggestion here's mama my way of remembering these which will include the mama mo trick but the first thing I suggest you do anytime you're looking at muscles of the lower leg and you can see the patella find the patella first always find the patella first and then walk your finger up from the patella and find rectus femoris I can't see a lot of it here just a little bit of rectus femoris and then from there let's find some other quads well if you move your finger medially which is this direction you'll find vastus medialis this muscle here as fast as medialis so I've got this muscle I've got this muscle then you know what other muscles are have some characteristics that make them easier to identify I think the S shape of the Sartorius is very useful so here's a muscle kind of curving across the medial thigh that's Sartorius things get a little bit messy here in the middle I might just skip that for a second but the other trick I know is that when I look at the back of the thigh they are the hamstrings are found there and they're kind of can be bisected and there's some muscles on the medial side and some on the lateral side so if you can find the line where those muscles are bisecting bisected now I can say Oh on this side of the muscle of the hamstrings are some muscles and on this side are some others or specifically since I'm looking at the mama-mama medial side of the thigh I know I should be looking for semimembranosus and semitendinosus so so my tendinosis is a little bit longer skinnier and it is superficial to semi member gnosis which is this wider muscle here well remember I bisected the hamstrings and I can still see some muscle just a little bit of it well that must be the other muscles of the hamstring I don't know is it biceps femoris long head or short head but I know that's biceps femoris probably long head because it's so long then also I've got left is a little bit of a peekaboo muscle here and here and I know that the other muscles I should find on the inner thigh are the muscles that pull my inner thigh towards the midline of my body the adductors this is adductor longus this is adductor Magnus here's my butt muscle gluteus maximus and in the next video we'll learn about gastrocnemius that big muscle of your calf so that's not easy but if you remember some of my tricks and know how and when to properly apply them you can figure out some of these muscles and to prove it to yourself why don't you do it with this model is this a model this diagram don't know where to start sure you do find the patella and then