Hello, everyone! This is Joao from Kenhub, and welcome to another anatomy tutorial. As you probably guessed, yes, we’re talking about the bones and ligaments of the foot today.
So, what I’m going to do on this tutorial is go over the different bony structures that you find on your foot as well as the main ligaments that you find attached to these bones because, keep in mind, we can go into a lot more detail when it comes to ligaments, but we will do so in a different tutorial.
Without further ado, I want to just list the different bones that we’re going to be covering here on this tutorial and that you find on your foot, and these include the calcaneus, the talus, the cuboid. We find three cuneiform bones known as the medial, intermediate, and lateral cuneiform bones.
There’s also an avicular bone to be discussed, and the metatarsals, as well as the proximal, medial, and distal phalanges.
When it comes to the different ligaments that I’m going to be covering on this tutorial, we will talk about the lateral collateral ligament, the medial collateral ligament, and finally, we’re going to look at the long plantar ligament.
Now, we’re ready to start off with the different bones seen… the first one here highlighted in green. This is the calcaneus, and the calcaneus is the largest bone of your foot.
This bone serves as origin point for different muscles, including the extensor digitorum brevis, the extensor hallucis brevis, and the quadratus plantae muscle.
It also serves as an insertion point for different muscles, three that I want to highlight here, specifically on the tuberosity of the calcaneus, and this includes the gastrocnemius, the soleus muscle, and the plantaris.
As I mentioned before, there’s this structure here that belongs to… that is part of the calcaneus, which is known as the tuber calcanei or the tuberosity of the calcaneus, which is a transverse elevation on the plantar surface of the calcaneus to which various muscles are, then, going to attach to as we saw also on the previous slide.
The tuberosity of the calcaneus will also serve as an origin point for different muscles, including the abductor digiti minimi and the flexor digitorum brevis. And you can clearly see here on these images, we’re looking, now, at the plantar side of the foot. And you see here the tuberosity of the calcaneus and the origin point for these muscles highlighted in green.
The next one on our list is going to be this one that you see now, highlighted in green. This is known as the talus or ankle bone and forms the lower part of the ankle joint through its articulations with the lateral and medial malleoli of the two bones of the lower leg: tibia and the fibula. And you can clearly see here the tibia and the fibula articulating with the talus.
The talus has an irregular shape, and it can be divided into three parts specifically. One is the head as you can see highlighted here in green, as well as the neck, and the rest of the bone then, we will call it as the body of the talus.
Now, let’s take a closer look at the different structures of the talus starting off with, then, the head of the talus, which is involved in a joint between the talus, an avicular bone, and the calcaneus, which then we call the talocalcaneonavicular joint – long name.
And it is part of the subtalar joint that enables, then, pronation and also supination of your foot or lifting the lateral and medial sides of your foot. That’s what we call pronation and supination.
Now, the other one is known as… the other structure is known as the neck of the talus as we’ve seen. And the neck of the talus is connecting the head, as you can see here, with the rest of this bone, which is then, the body, which is the next structure that we’re going to look at now: the body of the talus.
And this structure contains the trochlea tali that forms the lower part of the ankle joint or the talocrural joint with the tibia, fibula, and talus.
The ankle joint allows dorsal extension and plantar flexion of the foot.
So as you can see, the body and the head are, then, participating in all joints that are responsible for movement of your foot.
The next one that we’re going to be talking about, seen here highlighted in green, this is the cuboid bone. And as the name indicates, this bone is shaped as a cube and connects the foot to the ankle and that is also… It also provides stability to your foot.
There are a couple of muscles that will be attaching to the cuboid bone, and it includes the flexor hallucis brevis seen here, highlighted in green, and also the tibialis posterior will be attaching to the cuboid.
Now, the flexor hallucis brevis arises by a pointed tendinous process from the medial part of the lower surface of the cuboid bone, and the tibialis posterior will insert to the lower surface of the cuboid bone.
We’re going to start off with, then, the cuneiform bones, and this one is the medial cuneiform bone found on, then, the medial side of your foot, closer to your… or in the same direction as your toe, as you can see here.
This is the largest of the cuneiform bones, and the medial cuneiform bone is articulating with four bones specifically: the navicular, the second cuneiform or the intermediate cuneiform, and the first and second metatarsal bones.
And you can clearly see here, this is the first metatarsal bone, the second metatarsal bone also articulating, the intermediate or second cuneiform, and the navicular bone—all articulating with the medial cuneiform bone.
This bone will also serve as insertion point for three muscles that are worth highlighting here. One is the tibialis anterior, seen here highlighted in green. The other one is the fibularis longus, also in green. And the other one, the tibialis posterior, which you can also see it here in green.
So all these muscles will use the medial cuneiform bone as an insertion point.
Moving on to another cuneiform bone that we briefly mentioned on the previous slides, this one is the intermediate cuneiform bone. This bone is wedge-shaped and has a thin end pointing downwards.
The intermediate cuneiform articulates with the navicular posteriorly, the second metatarsal bone anteriorly, and with the other cuneiform bones on either sides.
The intermediate cuneiform bone will also serve an insertion point for the tibialis posterior.
Now, we’re going to move on to the lateral cuneiform bone, as you can see here, the third one that’s on the list. And this bone is intermediate inside, when compared to the other two, is also wedge-shaped, and in terms of insertion points, it’s worth mentioning that this muscle here that you see highlighted in green, the tibialis posterior muscle will insert at the lateral cuneiform.
We’re going to move on to the next bone that you see here highlighted in green. This is known as the navicular bone, and the navicular bone is located a bit more proximally when compared to the cuneiform bones, and it articulates with different bones, including the talus proximally.
As you can see here, here is the talus articulating with the navicular bone, as well as this one here, the three cuneiform bones which articulate distally. And finally, the cuboid bone, which will then articulate with the navicular bone laterally.
Now, the tibialis posterior is the only muscle that attaches to the navicular bone, and the main portion of the muscle inserts into the tuberosity of the navicular bone.
And still on the navicular bone, I would just like to make a point that there is usually an accessory navicular bone that may be present in two to fourteen percent of the population.
We’re now ready to move a bit closer to the toes – so these bones here that are known as the metatarsals.
And the metatarsals are part of the bones of the mid-foot. They’re named by numbers and start from the medial side, as you can see here. We’re looking, now, at the plantar side of the foot.
And here is the medial side, which is the same side as the big toe, going all the way to the little toe, and we start counting as one all the way to five. So that’s how we name them.
And the first metatarsal bone is the strongest and most prominent of the group.
The metatarsal bones will serve as an origin point for the dorsal interossei muscles, as you can see here, highlighted in green.
The metatarsals are convex in shape. They are long bones and give the foot its arch. So it helps form the foot arch.
They work with the different ligaments and tendons of different muscles to provide movement of the foot.
On the fifth metatarsal, there is an important structure that you now see here, highlighted in green, and worth talking about. This is known as the tuberosity of the fifth metatarsal bone.
And this structure serves as an insertion point for this muscle that we’re going to be seeing here, the fibularis brevis, also known or sometimes called as a peroneus brevis.
We are now ready to talk about the different bones that define the toes. These are known as the phalanges of the foot because you also have phalanges in your hand – those bones that make up your fingers.
There are 14 phalanges on each foot, three phalanges on each toe, but on the big toe, we only find two phalanges.
We’re going to start talking about, then, the proximal phalanges, as you can see here highlighted in green. They are the largest bones in your toes, and they form the base of the toe, as you can see here. So they form the base of every toe on your foot.
They are connected to the metatarsals by cartilage. And they are identified by numbers as well, starting with one of the largest… that we find on the largest toe, which is the big toe, and then goes all the way to the fifth one, which is found, then, on the little toe.
In terms of insertion points, it is important to mention that the proximal phalanges will serve as insertion points for the extensor hallucis brevis and also the lumbrical muscles.
So the advantage of having proximal phalanges or phalanges at all is that these are able or allow your foot to actually bend. So it’s quite important when you balance your body and as well when you flex your foot when you walk, or run, or jump.
So these provide a bit more flexibility in terms of movement.
It is time for us to move on to the next set of phalanges, seen here highlighted in green. These are known as the middle phalanges, and every toe has one but with the exception of the big toe. As you can clearly see here, the big toe only has a proximal phalanx and a distal phalanx, so no middle phalanx for the big toe.
And the middle phalanges are a bit smaller when compared to the proximal phalanges as you can also see here on this image.
These structures will also serve as insertion point for one muscle that you see here highlighted in green, known as the flexor digitorum brevis.
The middle phalanges are held together by different ligaments which, then, assist the muscles in the movement of the toes when a person walks.
Last set of phalanges that you now see here highlighted in green, known as the distal phalanges, which are located at the end of each toe. So the distal phalanges come at the end, right below your toenail.
These structures will serve as insertion points for different muscles. So from the second through fifth toes, the distal phalanges here will serve as insertion point for this muscle seen here highlighted in green: the extensor digitorum longus.
And at the distal phalanx of the big toe, you’re going to see that this muscle, seen here highlighted in green, the extensor hallucis longus, will be inserting on the distal phalanx of the big toe.
We are now ready to move on and talk about the different ligaments that you find on the foot (the most important ones), starting off with this one here, highlighted in green, or a collection of ligaments that are known as lateral collateral ligament.
Now, this is three ligaments or these are three ligaments run from the lateral malleolus to the bones of the foot, and the names indicate their origins and also insertions, starting off with the anterior talofibular ligament which runs from the… or between the talus and the fibula. And also, you will find a posterior one which is going to go also from the talus all the way to, then, the fibula.
And finally, you find this one here, this ligament known as the calcaneofibular ligament, which then runs between the calcaneus and the fibula as well.
All these ligaments have one purpose, and the main purpose is to stabilize the ankle on the lateral side.
If you stand on the lateral edge of the foot, they get tensed and prevent the foot from disconnecting from the lower leg.
The next ligament that we’re going to see now, highlighted in green, is known as the medial collateral ligament, also known as the deltoid ligament.
And the ligament runs from the medial malleolus to the bones of the foot.
Like we saw in the lateral collateral ligaments, the names also indicate the origins and insertions of these ligaments. And the medial collateral ligament has different parts that sometimes are distinguished as separate ligaments, but these parts are the tibionavicular part, the tibiocalcaneal part, the tibiotalar part or the anterior tibiotalar part, and the posterior tibiotalar part.
Now, the main function of the medial collateral ligament is to stabilize the ankle on the medial side. So if you stand on the medial edge of your foot, it gets tensed and prevents the foot from disconnecting from the lower leg.
We’re ready to move on to the next ligament here, the largest on your foot, this is known as the long plantar ligament. It is a long firm ligament on the plantar side of the foot which connects this bone here, the calcaneus to, then, the cuboid bone. And the long plantar ligament is the longest ligament of the foot.
And as the long ligament, it is worth talking about the different origin and insertion points for the long plantar ligament.
So starting off with the origin point, this long ligament will start off at the tuber calcanei or the tuberosity of the calcaneus, right about here.
And from there, it runs to the cuboid bone and then fans out towards the insertion points which will be the second through fifth metatarsal bones.
Now, also important to add here that this muscle that you see highlighted in green will originate from the long plantar ligament. And this is known as the flexor digiti minimi brevis.
And as for function, the main function of the long plantar ligament is to stabilize the longitudinal arch of the foot and also prevents the foot from becoming flat.