This video was sponsored by Kenhub. More on them at the end of the video. Hello and welcome! My name is Patrick, and in this video I'll teach you some of my tips and tricks for remembering all of the skeletal muscles of the lower limbs that you would see in an anatomy class. And to make this lesson more manageable for beginners, I'll present the list in smaller chunks of 4-8 muscles. You can find a list of those sections and timestamps in the description below. And with that out of the way, let's get into the muscles. This video is packed. Today we're going to cover the biggest muscle, the longest muscle, some of the tiniest muscles, and some muscles that not everyone has. We'll start with the chunk I'm calling big hip, since it's got some of those big superficial, visible muscles. The muscle you probably know as the hip flexor, the iliopsoas muscle, is made of two muscles, the iliacus and the psoas major, which work together as your main hip flexors. The iliacus gets its name from its wide origin on the inside of the ilium, that big portion of the pelvis. Meanwhile, the psoas major originates up on these vertebral bodies and joins the iliacus at a common insertion on the femur. The other psoas, the psoas minor, is much smaller, weaker, and connects the lumbar vertebrae to the pubis. Because of that, it might help flex the spine, but unlike the psoas major, it's not a hip flexor. So it gets its name because it's physically near the psoas major. Not because it does the same action. Moving to the backside, you already know that this muscle is the gluteus maximus, but there are two other gluteal muscles, the gluteus medius and the gluteus minimus. The glute max is easy to remember. It's the most massive muscle in the human body, and probably your favorite muscle. The other two, though, are jumbled up with all these other smaller hip muscles. But I can always tell the glute muscles apart because they all originate on the backside of the ilium and insert on the femur. So once you've identified the muscle's origin, it's just a matter of size. The maximus is the biggest, the medius is under that, and the minimus is the smallest. The glute medius and minimus attach pretty high up on the femur, but the glute max inserts all the way down here via the IT or iliotibial band. But it actually shares the tendon with another hip muscle, the tensor fasciae latae, or TFL. I remember this one by imagining that I was balancing a latte on my hip right on top of the tensor fasciae latte. But if you're more scientific, you can remember that this muscle pulls on this big band of connective tissue, or fascia, and it's a lateral, or latte, muscle. If you were to cut away the gluteus maximus, you'd find a bunch of smaller hip muscles that help with everything from stability to rotation. We'll look at all of these from top to bottom. Get it? Directly inferior to the glute minimus is the piriformis. It supposedly gets its name from being pear-shaped, but I don't know about you, I don't really see it. I personally remember this one because it's the muscle that you stretch in pigeon pose, so you've got the word overlap between piriformis and pigeon. Now the hip has a few paired muscles, and the muscle inferior to the piriformis is literally one of two twins. It's called the gemellus superior, which is very helpful, it has superior in the name so we know it's going to be above its twin, gemellus inferior. But between them is the obturator internus, a muscle that originates at this big opening here, what's called the obturator foramen. Super clever naming, I know. But on the other side of the obturator foramen is the obturator externus muscle. And I know that seems counterintuitive based on this diagram. Why not just call them the obturator superior and inferior? Well check out the positioning on all these hip muscles. They all pack into this little bundle between the coccyx and the femur. Meanwhile, the obturator externus starts on the pubis and tucks under the rest of the hip joint. So while the other muscles are cuddling like teenagers away at summer camp, the externus is watching jealously outside the fence. Hence externus. Finally, the quadratus femoris is this square-shaped muscle that's inferior to all of them. We've seen this root before in this series, quadratus. It always points to a square-shaped muscle. Then femoris gives us our last clue. It's a square shaped muscle that attaches to the femur. As far as how to remember this chunk, some students like the mnemonic, patched goods often go on quilts, which corresponds with the muscles from superior to inferior. Piriformis, gemellus superior, obturator internus, gemellus inferior, obturator externus, and quadratus femoris. Moving on to the thigh muscles, I'm going to chunk them into the following groups. The quadriceps, hamstrings, and adductor group. But I'm going to start with kind of a misfit, the sartorius, the longest muscle in the body. It goes all the way from the front of your pelvis down to the top of your tibia, and because it takes such a long, winding road, it does everything from hip flexion, external rotation, and abduction. Yes, abduction. Even though it overlaps with the other hip adductors. When the sartorius alone contracts, it causes the leg to abduct. I never had any mnemonics for this one, I always treated this one like it was a special piece of trivia. Like, after repeating, the sartorius is the longest muscle in the body over and over again, Again, it just kinda stuck. But if you like the etymology tips, sartor is the Latin root for tailor, and tailors used to sit cross-legged, which is how you test the sartorius. I don't know if that'll help the name stick, but at least now you have two fun facts about this muscle. More familiar though are the big strong quadriceps. As the name implies, there are four quadricep muscles, and they all insert on a common patellar tendon, and they all work together to extend the knee. Three of them originate on the femur itself. The vastus lateralis, vastus intermedius, and vastus medialis. Meanwhile, the big rectus femoris starts all the way up here past the hip, so it's both a knee extensor and a hip flexor. The biggest confusion students have with the quads is telling the difference between the vastus intermedius and the rectus femoris since they overlap. But remember, rectus means a long and straight muscle, and the rectus femoris is longer and straighter than the other quads. On the back side of the thigh, you'll find the three hamstring muscles. The most lateral is the biceps femoris, which implies two heads, like the biceps brachii, but it's not super obvious where they are at first. The long head of the biceps femoris originates on the ischial tuberosity, which is part of the pelvis, and the short head originates on the backside of the femur, which you're not going to see on the traditional anatomic position diagram. Your other hamstrings, the semitendinosus and semimembranosus, are more medial. I remember these because the semitendinosus is thinner and more tendon-y looking, while the semimembranosus is wider and looks more like a sprawling membrane to me. Then as far as memorizing the location of all the hamstrings, I remember that the membranosus is medial, while the biceps femoris was further away. Finally in the thigh, there are five medial muscles that make that one awkward machine at the gym possible. This motion is called adduction, and all five of these muscles work together as the adductor group. Three of them have adductor in the name. From distal to proximal, they're the adductor magnus, adductor longus, and adductor brevis, or MLB. Yes, just like Major League Baseball. If you want to remember these muscles because Major League Baseball players tend to have nice thighs, I won't stop you. Personally, I find that identifying the muscle based on shape, name, and position is still the most reliable way to label them. The biggest hint here is that the adductor brevis is the shortest one, while the longest is long and strong. Then the magnus has that wide sprawling shape, so I personally think of the magnus as like the king of the crotch, sprawling from the pelvis all over the kingdom of the femur. But on the medial border of the crotch kingdom is one last muscle. The gracilis is a long thin muscle that goes all the way from the pubis down to the tibia. So it not only adducts the thigh, it does a little knee flexion as well. Because this one is the longest, thinnest, and most delicate of the adductors, you need to remember to be graceful when handling the gracilis. The final adductor is the pectineus, which is the most superior of the adductor muscles. And this is the spiciest of my memory devices, but I remember pectineus because it's the closest to the peaches of the butt. Last little side note, some lists include a muscle called the articularis genus, a small muscle that's sometimes considered part of the vastus intermedius, but sometimes gets identified as its own muscle. If your professor isn't quizzing on it, don't worry about it. Now that we're done with the thigh, we'll divide the lower leg into four big chunks. Anterior, medial, posterior, and lateral. Truth be told, the anterior muscles we can almost glance over. Like the tibialis anterior is a dead giveaway. It's on the anterior, or front, of your tibia. And just like all the other predictable anatomy names, the extensor digitorum longus extends the digits of the foot or toes. And the extensor hallicus longus extends the halix, or big toe. As a little pro tip, while all of these have different, refined actions, they all cross the front of the ankle, so they'll all contribute to dorsiflexing the foot. If you ever get lost, you can feel these by taking off your shoe, doing these motions, and the muscles will pop up. But you'll notice that there's another tiny muscle that helps dorsiflex the foot. This tiny guy, called the fibularis tertius. It connects this last distal part of the fibula to the metatarsal on the pinky toe side, and is usually confused with parts of the extensor digitorum longus. It's one of the three fibularis muscles, named of course because they originate on the fibula, so they're easy to remember. The fibularis longus is easy to spot if you evert your ankle, it'll pop out on the sides of your legs. Then a little further down is your fibularis brevis, another muscle that everts the ankle. They're a straightforward group to remember. They're on the fibular side and are labeled according to size. Side note, some anatomists call the fibularis group the peroneals, but they still follow the same naming conventions. The biggest one is longus, the shortest one is tertius, and the middlest is brevis. The posterior side of the lower leg has some familiar muscles, too. The gastrocnemius I remember because its big muscle belly reminds me of a big stomach, with the root gastro in it. There's also the soleus, which is deep to the gastroc, but puts some soul in your step. They both insert on the heel with their shared Achilles. tendon, the thickest tendon in the body. Coincidentally, the longest tendon in the body also inserts on the heel. It comes from the plantaris, a small muscle that's tucked behind the lateral head of the calf. Of course, it gets its name because it helps you plantar flex your foot. Right next to the plantaris muscle belly behind the knee is the popliteus muscle. And this thing is unique because without it, you wouldn't be able to unlock your knee. I've always remembered this one because you could hold one pop-tart in your popliteal region and you could only bend your knee thanks to your popliteus muscle. It may be my dumbest memory device, but it is the most fun. As you work your way more medially, you'll find the muscles of the tarsal tunnel with one of the classic mnemonics of anatomy education. Meet Tom, Dick, and Harry. Tom is the tibialis posterior, the muscle that pivots under your medial malleolus and is the muscular support for your arch. Dick is the flexor digitorum longus, which lets you curl your toes, and Harry is the flexor hallicus longus, which lets you curl your big toe. As a group, these tiny muscles start near your knee and send tendons all the way down your leg and under your foot to exert their action. Before we go on, a quick note on the foot. You'll often see these muscles presented in four distinct layers, which can be useful for dissection, but I'm going to take a slightly different order for memorization. Also, it's important to know that there are two big arches in the foot. There's the longitudinal arch, which runs long ways from heel to toes, and the transverse arch, which cuts across the metatarsals. I mention that now because some of these muscles run directly along those arches, and when they contract, they support the shape of that arch. If you remember the sides of the hand, then you remember that the anterior side was the side with all the flexor muscles, while the posterior was the extensor side. We see something similar in the foot. On the dorsal side, or top side, you have muscles that extend the toes, and extend the big toe, or the helix specifically. We've already seen the extensor digitorum and extensor hallicus that originate in the lower leg, but the extensor digitorum brevis and extensor hallicus brevis originate on the foot and insert on their respective toes, thus their brevis. The giveaway with these muscles is their insertion. Does it insert on the toes? Then it's the extensor digitorum. Does it insert on the big toe? It's the hallicus brevis. Also on the top of the foot, we'd find dorsal interossei, just like we found in the hand. And again like the hand, the dorsal interossei abduct the metatarsals. Meanwhile, the plantar interossei adducts the metatarsals. They help with a bunch of other actions too, but this helps us remember them by associating them with their matching muscle of the hand. If you haven't watched the hand unit yet, we use the mnemonic pad-dab. Palmer adducts dorsal abducts, or in this case, The plantar adducts, but the mnemonic still holds. As we cross over to the plantar side, we see a ton of different muscles and connective tissue. On the medial side of the foot, you find the abductor hallicus, which abducts the big toe. Nice and straightforward. Given the position of this muscle, it clearly pulls the hallux out to the side. But there's also a separate adductor hallicus. As the name implies, it pulls the big toe into the rest of the foot. It's this wider, triangle-shaped muscle that spans across the metatarsals. But here's what I find so cool. When you adduct the helix, you end up tensing both arches of the foot. So the adductor helicus helps maintain the shape of the arch. On the opposite side of the foot is another single phalange mover, the abductor digiti minimi. You already know that digiti minimi means pinky or pinky toe, so this muscle inserts on that toe and abducts it. But look at how it runs from heel to toe. That means it also supports the longitudinal arch. The final muscle in this chunk is the flexor digitorum brevis, another straightforward name. It's a short muscle that bends all of the toes except the big toe, since that one already has two flexor muscles of its own. And of course, it supports the longitudinal arch. Our last chunk of foot muscles includes everything else. The first one, quadratus plantae, is another giveaway. It's a quadratus, which means square shaped. And plantae, so it's on the plantar aspect of the foot. Next up is the flexor hallicus brevis. Again, dead giveaway, it's a small muscle that bends the joint of the big toe. Remember, the flexor hallicus longus was super long, originating all the way up in the lower leg. So as long as you can see a muscle that runs under the first metatarsal and the first helix, it should be pretty clear which one is longus and which one is brevis. On the opposite side we'll find its counterpart, the flexor digiti minimi brevis, a short muscle that bends the pinky toe. And finally, we have a set of lumbricals just like in the hand musculature, muscles with these long tendons that run all the way to the tips of the toes. If you remember the hand lumbricals memory device, it turned the hand into an upside down capital L. The foot lumbricals flex and adduct the toes. So if you look for it, you can kind of see a lowercase L. Now, these are just the tricks I personally use to remember these muscles, but if you want another great resource for learning anatomy, then you need to check out Kenhub. I use them all the time when researching and writing these videos, and for this series in particular, their written articles and Atlas of Muscles have been extremely helpful in refreshing my knowledge of some of those deeper, smaller muscles. They've also got an enormous library of in-depth videos about muscles, histology, vasculature, nerves, and everything else you'd need to know in anatomy class. All those beautiful illustrations that you saw in this video came from them. And in addition to their library of content, I also love Kenhub's quiz feature. They allow you to build custom quizzes with different difficulties, and they give you feedback so you can figure out where your weaknesses are. You can use most of Kenhub's features for free, but if you want full access to all of their learning content and quizzes, then go to khub.me slash corporis to get 10% off your subscription. They've also got a no questions asked 7 day money back guarantee, so you can try out the premium version for 7 days, and if you don't like it, get your money back. If you want to see the next video in the muscle memorization series, then check out this playlist here. Don't forget to subscribe! Leave a like on the video, have fun, be good. Thanks for watching.