Video: Main muscles of the lower limb

Hey everyone! This is Nicole from Kenhub, and in this tutorial, we'll be talking about the main muscles of the lower extremity, otherwise known as the lower limb, as well as some of their functions.

So, in this tutorial, we’re mainly going to be focusing on the functions of the muscles of the lower limb as it’s just the basics introduction, but before we go on to talk about these in more detail, let’s begin by defining, what is a muscle? And a muscle is a bundle of fibrous tissue that contracts to produce movement, and in this image, you can see the quadriceps femoris muscle highlighted in green on our image. But the other question we want to ask ourselves today is, what is the lower extremity? And the lower extremity is the entire human leg from the hip to the toes.

We’re now looking at an image of our anatomical male, and he has, as you can now see, the quadriceps femoris muscle highlighted in green overlaying his lower extremity, and this muscle is most frequently used when running, as we can see in this image.

Okay, now that we’re finished defining what is a muscle and what is the lower extremity, I want to talk about some divisions of the lower extremity.

So, there’s several regions that we’re going to be talking about today and we’re going to start from top to bottom as we always do – so superior to inferior – and we’re going to start by looking at the muscles of the hip region, which is located in this green section on our right just here, followed by the muscles of the thigh, followed by the muscles of the leg, and finally, followed by the muscles of the foot, which is highlighted in green down the bottom.

So as we mentioned, we’re going to start with the muscles of the hip region. And the muscles in this area can be divided into two groups – the first one being the hip flexors and the muscles of the outer hip – and we’re going to go through these now, of course, in that order.

So let’s, of course, begin with the hip flexor muscles, and the first muscle that we want to talk about today is the iliopsoas muscle, which you can see highlighted in green on our image on the right. So, the iliopsoas muscle is a muscle of the inner hip and it actually comprises of two muscles which you can kind of see in this image. So, firstly, there’s the psoas major which you can see highlighted in green, and secondly, the iliacus muscle which you can now see highlighted in green.

Now, I just want to bring this image to the center a little bit more just to demonstrate something to you. So, obviously, you can see that the iliacus muscle and the psoas muscle have different origin points, but they both have the same insertion point which you can see in the lower half of the image, and basically, the two parts of the iliopsoas muscle unites just below the inguinal ligament which I’m demonstrating by my blue line just here, and the circle is just pointing out the common insertion of this muscle.

Now, let’s just come back to our image of the iliopsoas muscle altogether. Let’s talk a little bit about its innervation. So, the iliopsoas muscle is innervated by the femoral nerve as well as direct branches of the lumbar plexus. And in terms of its function, it is the strongest flexor of the hip joint which makes it a really important muscle for walking – just like our woman walking across the bottom of our image just here. This iliopsoas muscle also helps to stabilize the pelvis, and it facilitates the lateral rotation of the thigh. It also supports the straightening of the upper body in the supine position and straightens the body during sit-ups.

Okay, now, let’s move on to talk about the muscles of the outer hip, and the first muscle I want to talk about is the gluteus maximus muscle which you can see in green on our right, and as you can see, it’s a pretty large muscle which takes up the majority of the buttock.

The gluteus maximus muscle is also the largest and most superficial muscle of the three gluteal muscles – and we’ll talk a little bit more about the gluteal muscles a little bit later in this tutorial. And another interesting thing about the gluteus maximus muscle is that it helps form the gluteal sulcus which you can see in this image down here, although it doesn’t actually represent the lower margin of the muscle but instead being formed as a result of an arcuate enhancement of the fascia. In other words, it’s created by the fascia and not by the muscle.

Let’s briefly talk about its function, and as you can see, the upper fibers of the gluteus maximus muscle, when contracted, cause an abduction at the hip whereas the lower fibers of the muscle cause adduction of the hip – and you can see the arrow pointing out the direction of adduction. When they’re working together, the two muscles form a really powerful extensor and they help to rotate the hip outwardly. And in addition to these, the gluteus maximus muscle also stabilizes the hip in the sagittal and coronal planes – and you can see both of those planes in our little blue boxes down the bottom.

The next muscle we want to talk about in this region is the gluteus medius muscle which you can see in green on our right, and this is the second of the three gluteal muscles that we talked about a little bit earlier, and this muscle forms the middle layer of those three muscles. It’s also one of the major internal rotators of the hip. So talking about its function, its anterior fibers, as you can see highlighted in blue on our right, facilitates flexion and internal rotation, and that dotted line is just to indicate the movement of the hip going into the screen – so it’s turning inwards, not outwards – and the posterior fibers of this muscle help facilitate extension and external rotation of the hip.

The entire muscle when it works together helps with the abduction of the hip – so, movement outwards away from the midline of the body – and, of course, it helps with the stabilization of the pelvis in the coronal plane.

The most deeply located and the smallest of the three gluteal muscles is the gluteus minimus muscle – and you can see that highlighted in green on our right. And the function of this muscle is similar to that of the gluteus medius muscle in that contraction of the anterior fibers results in flexion and internal rotation whereas the contraction of the posterior fibers of this muscle results in extension and external rotation. The entire muscle when it works together abducts the hip and it also stabilizes the pelvis in the coronal plane.

Let’s move on now to talk about the piriformis muscle, which is another muscle of the outer hip and an external rotator of the hip. As you can see, it’s a stabilizer of the hip and it also helps to facilitate abduction, extension, and external rotation of the hip joint.

Moving on now to the tensor fasciae latae muscle. As you can see, the tensor fasciae latae is a thin muscle of the gluteal region – and you can see how thin it is on this image – and it’s superficially located and it can be easily palpated especially in athletes who engage and strengthen the hip muscles. As its name suggests, the tensor fasciae latae muscles tenses or tightens the fascia lata and it also sustains tension of the iliotibial tract. At the hip joint, contraction of the tensor fasciae latae muscle results in abduction, flexion, and internal rotation of the thigh.

Let’s move on now to a different set of muscles – the muscles of the anterior thigh – and as you can see, the thigh can be divided into the anterior compartment and posterior compartment, and the hip adductors. And the first muscle we want to talk about in the muscles of the anterior compartment of the thigh is a large four-headed muscle known as the quadriceps femoris – and you can see it highlighted on our image and we talked about it earlier in the introduction to this tutorial.

So as you can see, it’s a very large muscle and it makes up the bulk of the anterior thigh almost completely covering the femur, and it’s one of the strongest muscles of the human body. You probably have heard of it when we talk about the quads. So quadriceps in running or when you do the stretch where you bend your knee and hold your foot against your buttocks – that’s the big muscle that we’re stretching at the front of the leg just here.

So, the quadriceps femoris muscle, as indicated by its name, has four muscles and these are the rectus femoris muscle, the vastus medialis muscle, the vastus intermedius muscle, and the vastus lateralis muscle. We’re not going to talk through each of these. Instead, we’re going to talk about the quadriceps femoris muscle’s function as a whole, and we should note that quadriceps femoris is important as it’s the only extensor of the knee joint, and another function of the quadriceps femoris is to facilitate hip flexion.

The other muscle of the anterior thigh is the sartorius muscle. As you can see, it’s a long thin, superficially-running muscle. And in this image, we can see the sartorius muscle isolated and the hip flexed and the knee extended so that we can see some of its functions a little bit more clearly. So, at the hip joint, the sartorius muscle facilitates flexion, abduction and external rotation while at the knee joint, the muscle facilitates flexion and internal rotation.

Let’s now look at the posterior thigh muscles. Now, the main muscle of the posterior thigh – again, you might have heard of through if you run or if you exercise – there’s a major group of muscles called the hamstring muscles, and there are three of these – the biceps femoris which you can see dotted out in blue just here, the semimembranosus, and the semitendinosus muscle. And let’s talk about each of these individually.

And as we mentioned, the first one of these is called the biceps femoris muscle, and the biceps femoris as you can tell by the name is a two-headed muscle and the biceps femoris has a long head and a short head.

So, we’re just going to bring in this other image where we can see the left thigh from a lateral view and the biceps femoris, of course, is highlighted in green, so that means that our anterior is over here and our posterior is over here on the right. We’re looking in this image because we can see that at the hip joint, the long head of the biceps femoris muscle extends the hip and helps to stabilize the pelvis in the sagittal plane whereas at the knee joint, the entire muscle facilitates flexion and external rotation.

Now let’s have a look at our second hamstring muscle, and the second hamstring muscle is the semimembranosus – so-called because it has a flat, membranous shape. And the muscle is located medially in the posterior compartment of the thigh, as you can see in the image. So let’s come back to our lateral view of the pelvis and the thigh where we can see the semimembranosus muscle highlighted in green. And the semimembranosus muscle extends the hip and stabilizes the pelvis in the sagittal plane. In addition, it also facilitates flexion and internal rotation at the knee joint.

Okay, coming back to our base image of the thigh from the posterior view, we can see the semitendinosus muscle highlighted in green, which is our last muscle of the hamstrings. And the semitendinosus muscle extends the thigh and stabilizes the pelvis in the sagittal plane as well as facilitating flexion and internal rotation of the knee joint.

Alright, let’s move on now to the hip adductors. And the hip adductor muscles are part of the musculature of the inner thigh, and the first of these muscles that we’re going to be talking about is called the pectineus muscle, which we can see just here on our right. And you can see from the image that it’s a flat muscle and it helps to stabilize the pelvis in a coronal plane as well as the sagittal plane and this muscle also facilitates the adduction, the external rotation, and slight flexion of the hip joint when it contracts.

Let’s move on now to the adductor magnus muscle and, as you can tell from the name – magnus – it’s a very large muscle and is in fact one of the largest muscles in the human body. The adductor magnus muscle facilitates adduction, external rotation, and the extension of the hip joint, and it also helps to stabilize the pelvis in the coronal plane. The adductor longus muscle is also a relatively large muscle as you can see on the image on the right, and this muscle facilitates both adduction and flexion of the hip joint as well as stabilizing the pelvis in both the sagittal and coronal planes.

So lying deep to the adductor longus muscle is the short adductor brevis muscle – and you can, of course, see that on our right highlighted in green – and contraction of this muscle facilitates the adduction and flexion of the hip joint. It also helps stabilize the pelvis in the coronal and sagittal planes.

Let’s move on now to another muscle that’s located in our leg region and is also considered a hip adductor muscle, and this muscle that you can see on the right in green is the gracilis muscle. And the gracilis muscle is the most superficial and most medial muscle of this group and it facilitates the adduction and flexion at the hip joint. In addition to that, it also facilitates flexion and internal rotation at the knee joint.

Alright, now let’s move down to our region of the leg. And like our previous regions, the leg can be divided into several compartments – the anterior compartment, the lateral compartment, and the posterior compartment. And like the compartments of the thigh, the muscles within each compartment have related functions, so listen out for those as we come to them.

Alright beginning with the muscles of the anterior compartment of the leg, do note that these muscles are all associated with dorsiflexion of the foot as well as its inversion or eversion, so just keep that in mind as we talk through them. And let’s begin with a muscle known as the tibialis anterior muscle, which you can see highlighted in green on the right and, of course, we’re looking at an anterior view of the right leg.

So I’m just bringing in another image where the tibialis anterior muscle is isolated so that you can see the function of it a little bit more clearly. So the tibialis anterior facilitates the dorsiflexion of the talocrural joint and it also helps with the inversion or supination of the foot at the subtalar joint. And the tibialis anterior muscle is also the leading muscle for the neuromuscular pathway to the ankle. Now, what does that mean? That basically means that there’s some major nerves and vessels that follow the tibialis anterior from the knee to the foot, and I’ve drawn in for you in red the anterior tibial artery as well as the vein and we also have a deep fibular nerve.

The extensor digitorum longus muscle is responsible for the dorsiflexion of the foot at the talocrural joint or the ankle joint. It also extends the lateral four toes at the metatarsophalangeal and interphalangeal joints, and in this image, we can see this muscle extending or pulling the toes towards the leg. The extensor digitorum longus also assists in eversion or pronation of the foot turning the sole of the foot away from the midline of the body.

Let's move on now to the extensor hallucis longus muscle which, as we can guess, acts on the big toe. Like the extensor digitorum longus, the extensor hallucis longus is also responsible for the dorsiflexion of the foot at the talocrural joint and it extends the big toe at the metatarsophalangeal and interphalangeal joints which you can see in this image.

Okay, let’s move on and talk about the muscles of the lateral compartment of the leg, and again, we’re looking at an anterior view of our right leg, which means that the green muscle is on our lateral aspect of the leg and that green muscle is the peroneus longus muscle. And this muscle is also sometimes called the fibularis longus muscle. And again, we’re just bringing in an image that shows you some of the functions of the peroneus longus muscle. And the peroneus longus muscle is involved in plantarflexion of the foot in the talocrural joint as demonstrated by our little image down the bottom.

The peroneus longus muscle is also involved in pronation or eversion of the foot at the subtalar joint and the peroneus longus muscle also supports the transverse arch of the foot.

Another muscle with the name peroneus is the peroneus brevis muscle, which is also known as the fibularis brevis muscle, and again bringing in our lovely image demonstrating the functions of the peroneus brevis muscle, we can see that it’s involved with plantarflexion as well as pronation of the foot.

Okay, let’s move on now to the muscles of the posterior compartment of the leg. And the first muscle that I want to talk about is a sort of a combination muscle known as the triceps surae muscle. And the triceps surae is made up of two muscles – the gastrocnemius which we can see on the right in green as well as soleus which we can now see in green – and these two muscles are essentially a pair of muscles that make up the calf.

So, the gastrocnemius muscle is a bipennate muscle which we mentioned before of the posterior leg and that has two heads – like our two heads just here – and I’m going to bring in this posteromedial view so that we can have a look at the muscle a little bit more clearly. And in terms of its function, it helps with the plantarflexion of the foot as well as flexion of the knee joint.

Moving on to the soleus muscle, the soleus muscle is as we said the other muscle that makes up the triceps surae muscle and we’re just putting a transparent copy of our gastrocnemius over the top just here. and, again, looking at its posteromedial view, we can see that it’s involved – oh, and this is the point where I wanted to talk about the ankle joint because we can see it a little bit more clearly.

So as we mentioned, the soleus along with the gastrocnemius facilitates plantarflexion at the talocrural joint which is this point about here which is between the talus bone and the base of the tibia and the fibula, and, of course, we also call this the ankle joint. It also facilitates supination at the subtalar joint and I just want to circle this subtalar joint for you now. As you can see, it is the joint that is between the talus and the calcaneus.

Moving on to our plantaris muscle, which is a superficial muscle of the leg, and as you can see, it’s running superficially over the top of the soleus muscle. And in addition to plantarflexion of the foot, the plantaris muscle may also act to prevent the compression of muscles in the posterior leg during knee flexion.

Alright, let’s move on now to the tibialis posterior muscle. And the tibialis posterior muscle is another muscle of the leg. It’s one of the deep muscles of the posterior compartment of the leg; the other two muscles – the soleus and the gastrocnemius – being part of the superficial muscles of the posterior compartment of the leg. The tibialis posterior is part of the deep muscles. And as you can see in this posteromedial view, it’s very deep and it even lies in between the fibula and the tibia bones, and its function is to assist in plantarflexion at the talocrural joint or our ankle joint as we mentioned before, and also help with supination of the foot at the subtalar joint.

Let’s move on now to the flexor digitorum longus muscle. And as you can see, the flexor digitorum longus muscle is a deep muscle of the posterior leg and it’s fairly explanatory looking at its name as it facilitates plantarflexion at the talocrural joint as well as plantarflexion of the metatarsophalangeal and interphalangeal joints of the second to fifth digits. If we look at our image on the right, we can see the second to fifth digits in the blue circle and the metatarsophalangeal joints are these ones over here while the interphalangeal joints are these joints down here. And of course, with this arrow, you can see the plantarflexion. It also facilitates supination of the subtalar joint.

The flexor hallucis longus muscle is one of the smaller muscles of the posterior compartment of the leg and, of course, is one of the deep muscles and it acts mainly on your big toe. If you remember, hallucis is in reference to big toe which is named hallux in Latin. Again, bringing in our posteromedial view of the right leg, we can see the muscle running down the posterior aspect of the leg and it’s involved in plantarflexion of the metatarsophalangeal and interphalangeal joints of the big toe.

And again, let’s have a look at our circle, and the circle is pointing out our metatarsophalangeal joint of the big toe and now it’s moving down, and the second circle is pointing at the interphalangeal joint of the big toe – there’s only one in the big toe – and of course, the flexor hallucis longus muscle also helps with plantarflexion at the talocrural joint or our ankle joint. And it also helps with supination of the foot at the subtalar joint. The flexor hallucis longus muscle also supports the medial longitudinal arch of the foot.

Okay, let’s have a look at this short muscle of the knee joint, which is the popliteus muscle. And the popliteus muscle stabilizes the posterior knee region and I’m just bringing in an image of the popliteus muscle from a posteromedial point of view and the popliteus also facilitates flexion and rotation of the knee joint.

Alright, let’s move on to talk about the foot region and, of course, I’m just going to show the foot again. And in this image, you can see the dorsal region of the foot highlighted in green. As for the muscles of the foot, they can be divided into a dorsal aspect which are found on the dorsum of the foot as well as the plantar aspect which is found on the sole of the foot.

Let’s begin, of course, with the dorsal aspect of the foot, and there’s really only one muscle that we’re going to be talking about today in this particular section of the foot, and that’s the extensor digitorum brevis muscle. And in our image on the right, we’re looking at the right foot from a superior view. Let’s make things easier in terms of function. I’m just going to bring in this lateral view of the foot – so we’re looking at the right foot laterally. And as you can see, the extensor digitorum brevis muscle helps to extend the second to fourth toes at the distal interphalangeal joints. So, I’m just circling the second to fourth toes for you and these are the metatarsophalangeal joints while these are the proximal interphalangeal joints of the second to fourth toes.

If there's an extensor digitorum brevis muscle then, of course, you can be sure that there's an extensor hallucis brevis muscle and, of course, we're looking at a superior view but let's switch over to a lateral view. The extensor hallucis brevis muscle extends the metatarsophalangeal joint of the first toe, and over here, I'm just circling the metatarsophalangeal joint of the first toe.

Okay, let’s move on to the plantar aspect of the foot, and the plantar aspect of the foot which you can see highlighted in green, we can talk about these muscles in different regions, and these regions are going to be the medial part of the plantar part of the foot, the lateral part of the plantar part of the foot, and the central region of the medial part of the foot. And we’re going to begin with the medial side.

So, the medial side of the foot is this region just here in green. And because our big toe is the most medial toe of the foot, always where obviously all of these muscles are going to be related to the big toe or the hallux. So keep that in mind as we begin.

And in this image, we’re looking at the flexor hallucis brevis muscle, and we’re looking at it from an inferior view of the foot. So our medial aspect and, of course, our big toe is on the left side of the image highlighted in green. And this muscle is a short muscle found on the sole of the foot.

Let’s, of course, bring this muscle into a posteromedial view of the right foot, and in this image, we can see that the flexor hallucis brevis muscle helps with the flexion of the metatarsophalangeal joint of the big toe – the metatarsophalangeal joint being circled in blue. The flexor hallucis brevis muscle also supports the longitudinal arch of the foot.

Let’s move on now to talk about the adductor hallucis muscle, and as you can see in this image, it’s a two-headed muscle with our favorite little head popping up, and the function of the adductor hallucis muscle includes the flexion of the big toe at the metatarsophalangeal joint and adduction of the big toe. The adductor hallucis muscle also helps support the longitudinal and transverse arches of the foot – the longitudinal one being the vertical line in this image and the transverse one being the horizontal one. The adductor hallucis is anatomically located in the central compartment of the foot but the muscle is functionally grouped with the medial plantar muscles of the foot because it acts on the great toe or hallux.

Alright, let’s move on now to the abductor hallucis muscle, and as we can see, this muscle is involved with flexion at the first metatarsophalangeal joint as well as medial abduction and the abductor hallucis muscle helps support the longitudinal arches.

Let’s move on now to the lateral muscles of the plantar aspect of the foot, and the green section that I’ve highlighted is, of course, the lateral aspect of the foot, and is, of course, involved with the little toe. Keep that in mind as we look at our first muscle of this region – the flexor digiti minimi brevis muscle – and we know that it’s related to the little toe because it has digiti minimi in its name. As we mentioned, it’s a muscle of the lateral aspect of the foot. So looking at our posteromedial image of the right foot again, we can see the flexor digiti minimi brevis highlighted in green. This muscle helps to flex the little toe at the metatarsophalangeal joint.

Moving on now to the abductor digiti minimi muscle of the foot, we can see that this muscle is involved in flexing the little toe at the metatarsophalangeal joint, and it helps to abduct the little toe. The abductor digiti minimi also helps support the longitudinal arch of the foot.

Let’s move on to our final category of the plantar foot – the central region – and these are, of course, are located in the central part of the plantar aspect of the foot – so the middle of the sole of the foot. The first muscle I want to look at is the flexor digitorum brevis muscle and if you know any Latin, we know that -orum is plural – so we’re talking about many digits – and you can see in the image that this muscle has a relationship with the second to fifth toes.

And again looking at our posteromedial image, we can see that the flexor digitorum brevis muscle is involved with the flexion of the metatarsophalangeal and the proximal interphalangeal joints of the second to fifth toes. Of course, our metatarsophalangeal joints are in this blue oval and our proximal interphalangeal joints are in this blue oval. The flexor digitorum brevis muscle also supports the longitudinal arch of the foot, as you can see with the blue line.

Let’s move on now to a very interesting muscle called the quadratus plantae muscle, and as you can see in the image, it’s shaped like a quadrilateral which is why it’s called the quadratus plantae muscle. And the quadratus plantae muscle is involved in flexing the second to fifth toes and it also helps to redirect and augment the pull of the flexor digitorum longus. Now if you recall, the flexor digitorum longus flexes the second to fifth toes at the metatarsophalangeal joints and the proximal interphalangeal joints.

And I’m just going to bring in this image of the muscle just here, just to remind you what it look like. Also, in our image on the right, the tendons of the flexor digitorum longus are highlighted in blue and both of our images are of the right foot, but the one on the right is from an inferior view whereas the image in the blue is our posteromedial view. And as you can see in this image, the quadratus plantae inserts into the tendon of the flexor digitorum longus which helps increase the effect of the plantarflexion and of supination.

Okay, the next muscles I want to talk about are the lumbrical muscles, and they’re a group of four short muscles that act directly on the skeleton. And they, of course, help with flexion of the metatarsophalangeal joints of the second to fifth toes as well as help with extension of the interphalangeal joints of the second to fifth toes. It also helps with the adduction of the second to fifth toes.

Okay, the last group that we want to talk about in this tutorial are the interossei muscles, and there are plantar and dorsal interossei muscles so we’re going to talk about both of them in this section. And, of course, let’s begin with the dorsal interossei muscles which are found on the dorsal aspect of the foot and, of course, we’re looking at the right foot from a superior view looking downwards onto the dorsum.

We can see that they’re involved with the flexion of the metatarsophalangeal joints of the second to fourth toes as well as the extension of interphalangeal joints of the second to fourth toes, as well as the abduction of the third and fourth toes. And, of course, the plantar interossei muscles are found on the plantar aspect of the foot, and these help with the flexion of the metatarsal joints of the third to fifth toes as well as extending the interphalangeal joints of the third to fifth toes. They also help with the adduction of the third to fifth toes.

So thanks for sticking with me during this tutorial. Now, we’re going to briefly go through what we talked about today in our lovely summary.

We began with talking about the muscles of the hip region starting with the hip flexors which involved the iliopsoas muscle which is made up of two muscles – the iliacus and the psoas muscle. We then talked about the outer hip muscles, and, of course, there are three major gluteal muscles in this region – the gluteus maximus muscle which is the largest and most superficial of the gluteal muscles, gluteus medius muscle which is part of the middle layer of these muscles, and the gluteus minimus muscle which is the deepest of these muscles.

We also talked about the piriformis muscle which helps with internal rotation, and we talked about the tensor fasciae latae muscle which acts on the fascia lata.

We talked about the muscles of the anterior thigh, which included the quadriceps femoris which is one of the strongest muscles of the body and contains four muscles – rectus femoris, the vastus medialis, the vastus intermedius, the vastus lateralis – and we also talked about the sartorius muscle which is one of the longest muscles in the body.

We talked about the posterior thigh muscles and these included the biceps femoris muscle which is one of the three muscles of the hamstrings, the second muscle of the hamstrings is the semimembranosus muscle which is named because it’s flat and membranous, and we also talked about the semitendinosus muscle which is the third of the hamstring muscles.

We then talked about the hip adductors which included the flat muscle – the pectineus muscle. We talked about the adductor magnus muscle which is one of the largest muscles in the body. We also talked about the adductor longus muscle, which is part of this inner part of the leg, and we talked about the adductor brevis muscle as well as the gracilis muscle which is a superficial muscle running along the medial aspect of the thigh.

And then we went on to talk about the muscles of the leg which have three compartments – the anterior compartment and the lateral compartment and the posterior compartment. So let’s have a look at the anterior compartment of the leg. This compartment has the tibialis anterior muscle which is the muscle that guides a neurovascular pathway, the extensor digitorum longus muscle and the extensor hallucis longus muscle. On the lateral compartment of the leg, there was the peroneus longus muscle which is also known as the fibularis longus muscles, the peroneus brevis muscle which you can see down the bottom which is one of the extensor muscles of the leg.

Then we went on to talk about the posterior compartment of the leg which included the triceps surae muscle, which is, again, itself made up of gastrocnemius muscle and the soleus muscle which are the main muscles that make up the bulk of the calf and are two of the most superficial muscles of the posterior leg. We then talked about the plantaris which is a deep muscle of the leg as well as the tibialis posterior which is another deep muscle of the posterior compartment of the leg. We talked about the flexor digitorum longus muscle which helps with plantarflexion of the foot and the flexor hallucis longus muscle which acts on the big toe. We've talked about the popliteus muscle which is found on the posterior aspect of the knee.

Moving to the region of the foot, we looked at several sections. First of all, the dorsal aspect of the foot, and the main muscle that I talked about here was the extensor digitorum brevis muscle, and we also looked at the extensor hallucis brevis muscle. And then we moved on to talk about the muscles on the plantar aspect of the foot, and again, this could be divided into three parts – a medial part, a lateral part, and a central part. And in the medial part, we had a look at the muscles that are related to the big toe or the hallux so that includes the flexor hallucis brevis muscle, adductor hallucis muscle which, of course, adducts the big toe, and the abductor hallucis muscle which, of course, abducts the big toe.

We looked then at the lateral aspect of the foot which includes muscles that are related to the little toe otherwise known in Latin as the digiti minimi, so the flexor digiti minimi brevis muscle. We then looked at the abductor digiti minimi muscle which abducts the little toe, and then we moved on to the central muscles of the plantar aspect of the foot which included the flexor digitorum brevis muscle and the quadratus plantae muscle which augments the action of the flexor digitorum brevis muscle.

We also talked about the lumbrical muscles which is a group of four short muscles of the foot and then we talked about the interossei muscle which are on both sides of the foot – the plantar interossei muscles and the dorsal interossei muscles.

That’s all we have time for today. Thanks for watching.