Foot and ankle bones

Summary

This educational video script delves into the anatomy of the foot and ankle, highlighting the importance of physical models for understanding the complex structure of bones and their functions. It details the bones involved, from the tibia and fibula to the tarsal and metatarsal bones, and explains the mechanics of movement, including plantar flexion, dorsiflexion, inversion, and e-version. The script also discusses common injuries, the significance of foot arches for shock absorption and energy return, and encourages viewers to identify these bones on X-rays and recognize their importance in daily locomotion.

Takeaways

• 😀 The foot and ankle have a complex structure involving the tibia, fibula, and various other bones that work together to support the body's weight and facilitate movement.
• 🏫 The use of physical models, like 3D printed bones, is highly beneficial for understanding the anatomy of the foot and ankle, as it allows for a hands-on approach to learning.
• 👣 The foot has a set of tarsal bones, similar to the carpal bones in the wrist, and metatarsals and phalanges, which are analogous to the bones in the hand, but with differences due to their distinct functions.
• 🦿 The tibia is the primary load-bearing bone in the ankle, with the fibula playing a less significant role in weight support.
• 👣 The big toe, or hallux, has specific muscles and bony prominences that can be palpated and are important for foot movement.
• 🔍 The ankle joint, formed by the tibia, fibula, and talus, allows for dorsiflexion, plantar flexion, inversion, and e-version, with the talus' wedge shape influencing these movements.
• 🚶‍♂️ Inversion and e-version of the foot are more likely to cause injuries, especially when the foot is plantar flexed, due to the increased mobility and weaker joint stability.
• 🦴 The calcaneus, or heel bone, bears most of the body's weight and is a common site for ligament sprains and fractures.
• 👣 The foot contains three arches: the medial longitudinal arch, the lateral longitudinal arch, and the transverse arch, which are essential for shock absorption and energy return during movement.
• 👁️‍🗨️ Palpating the foot can help identify key bones such as the navicular, cuboid, and metatarsals, which are important for understanding foot structure and potential injury sites.
• 👣 The first metatarsal is significantly larger than the others, and the fifth metatarsal is the most commonly fractured, often due to landing on an inverted foot.

Q & A

What is the main purpose of discussing the bones of the foot and ankle in the video?

The main purpose is to educate viewers about the structure and function of the foot and ankle bones, emphasizing the importance of physical models for better understanding and learning.

How are the bones of the hand and foot similar?

Both the hand and foot have collections of bones that are remarkably similar, such as the carpal bones in the wrist and the tarsal bones in the foot, as well as metacarpals and metatarsals, and phalanges in both.

What is the primary load-bearing bone in the ankle?

The tibia is the primary load-bearing bone in the ankle, responsible for transferring body weight down into the foot.

What are the two bony masses that can be palpated on the ankle?

The two bony masses that can be palpated on the ankle are the medial malleolus of the tibia and the lateral malleolus of the fibula.

What is the function of the talus bone in the ankle joint?

The talus bone forms a hinge joint with the tibia and allows for plantar flexion, dorsiflexion, as well as a bit of side-to-side movement.

Why is the inversion and e-version of the foot easier to do when plantar flexed?

Inversion and e-version are easier to do when plantar flexed because the wedge shape of the talus bone opens up, creating more space between the bone and the space between the tibia and fibula.

What is the most common injury associated with the ankle ligaments?

Sprains are the most common injury associated with the ankle ligaments, which can be very painful and take a long time to recover from.

What is the significance of the arches in the foot?

The arches in the foot serve as shock-absorbing mechanisms, reducing the impact of body weight on the ground and improving the efficiency of locomotion.

How can you determine the type of arches you have in your foot?

You can determine the type of arches by wetting your foot, stepping on paper, and observing the shape and contact points left on the paper.

Why is the first metatarsal bone significant in the structure of the foot?

The first metatarsal bone is significant because it is the largest and plays a key role in supporting the body's weight and balance during walking and standing.

What is the most commonly fractured metatarsal and why does it occur?

The fifth metatarsal is the most commonly fractured due to landing on an inverted foot, where the weight is incorrectly distributed through the metatarsal instead of the calcaneus.

Outlines

00:00

🦶 Anatomy of the Foot and Ankle Bones

This paragraph introduces the topic of foot and ankle bones, emphasizing the importance of physical models for understanding bone structures. It compares the foot to the hand, highlighting the similarities and differences between the two, particularly the foot's role as a load-bearing structure. The paragraph details the bones of the ankle, including the tibia and fibula, and explains the load-bearing function of the tibia. It also describes the bones of the big toe, the hallux, and the malleoli, medial and lateral, which are palpable landmarks on the ankle. The importance of the talus bone in forming the hinge joint of the ankle is also mentioned, along with the range of motion allowed by the ankle's structure.

05:01

🤸‍♂️ Movement and Injuries of the Ankle

The second paragraph delves into the mechanics of ankle movement, focusing on the talus bone's wedge shape and its impact on inversion and eversion. It explains how dorsiflexion tightens the joint, making inversion more difficult, while plantar flexion allows for easier movement. The paragraph discusses common ankle injuries, such as sprains and fractures, often resulting from inversion or landing on an inverted foot. It also describes the bones anterior to the talus, including the navicular, cuboid, and cuneiform bones, and explains how to palpate these on one's own foot. The paragraph concludes with a mention of the metatarsals and the phalanges, noting the large size of the first metatarsal and the susceptibility of the fifth metatarsal to fractures.

10:03

🏃‍♂️ Function of Foot Arches in Locomotion

The final paragraph discusses the arches of the foot, their importance in shock absorption, and their role in efficient locomotion. It describes the three arches: the medial longitudinal arch, the lateral longitudinal arch, and the transverse arch, and how they are supported by connective tissues, muscles, and the bones' shapes. The paragraph explains that the arches act as a shock-absorbing mechanism, slowing the transfer of force from the body to the ground and reducing the impact on the body. It also touches on the energy return aspect of the arches, contributing to the efficiency of walking and running. The paragraph concludes with a simple test to observe one's arches by stepping on paper with a wet foot and examining the imprint left behind.

Keywords

💡Tibia

The tibia, also known as the shinbone, is a central bone in the lower leg that plays a crucial role in the video's theme of foot and ankle anatomy. It is the primary load-bearing bone, transferring body weight to the foot, especially at the ankle joint. In the script, the tibia's importance is highlighted by its connection to the ankle and the medial malleolus, which is palpable on the inner side of the ankle.

💡Fibula

The fibula is the thinner, lateral bone of the lower leg, mentioned in the video script as not being a primary load-bearing bone at the ankle. It works in conjunction with the tibia, forming part of the ankle joint and providing attachment points for various muscles and ligaments. The script points out the fibula's lateral malleolus, which is the bony protrusion on the outer side of the ankle.

💡Talus

The talus, also referred to as the ankle bone in the script, is a tarsal bone that articulates with the tibia and fibula to form the ankle joint. It is key to the hinge joint movement allowing for dorsiflexion and plantar flexion of the foot. The script emphasizes its wedge shape, which influences the ease of inversion and eversion of the foot.

💡Calcaneus

The calcaneus, commonly known as the heel bone, is the largest and strongest bone in the foot. As stated in the script, it bears most of the body's weight and is the point where the Achilles tendon inserts. The calcaneus is integral to the video's discussion of foot structure and function.

💡Metatarsals

Metatarsals are the long bones in the foot that form the arch and support the body's weight. The script describes how they are more likely to be fractured when landing on an inverted foot, emphasizing their role in load distribution and the potential for injury.

💡Phalanges

Phalanges are the bones of the toes, similar to the fingers in the hand. The script differentiates between the hallux (big toe), which has two phalanges, and the other toes, which have three phalanges each. These bones contribute to the foot's complex structure and function.

💡Arches of the foot

The arches of the foot are crucial for shock absorption and energy return during movement. The script identifies three main arches: the medial longitudinal arch, the lateral longitudinal arch, and the transverse arch. These arches are essential for the video's theme of foot function and biomechanics.

💡Inversion and Eversion

Inversion and eversion refer to the foot's ability to tilt inward and outward, respectively. The script explains how the wedge shape of the talus affects these movements, noting that inversion and eversion are more difficult when the foot is dorsiflexed and easier when plantar flexed. These movements are significant for understanding foot mechanics and potential injury risks.

💡Navicular

The navicular is a tarsal bone located anterior to the talus, resembling the curved hull of a ship as mentioned in the script. It is part of the medial column of the foot and plays a role in the foot's arch structure and movement.

💡Cuboid

The cuboid bone, named for its cube-like shape, is another tarsal bone that contributes to the lateral column of the foot. The script mentions its tuberosity, a bony prominence that can be palpated, which helps in understanding the foot's anatomy.

💡Cuneiforms

Cuneiforms are three wedge-shaped tarsal bones that articulate with the navicular and metatarsals. The script refers to them as 'one, two, and three' to indicate their position and function in the foot's medial column, contributing to the arch and supporting the body's weight.

Highlights

The importance of physical models in learning the structure of the foot and ankle bones.

Comparison between the structure of the hand and foot, highlighting their differences in dexterity and load-bearing.

The role of the tibia and fibula in the ankle joint, with emphasis on the tibia as the primary load-bearing bone.

Identification of the hallux, or big toe, and its significance in foot structure and movement.

Explanation of the medial and lateral malleolus and their palpable presence on the ankle.

The unique wedge shape of the talus bone and its impact on ankle movement and potential for injury.

The calcaneus, or heel bone, and its function in bearing most of the body weight.

The function of the tibia, fibula, and talus in forming the ankle joint and allowing specific movements.

Inversion and e-version of the foot, and their relation to the shape of the talus and potential for injury.

The role of ligaments in supporting the ankle and their susceptibility to sprains.

The potential for metatarsal fractures due to the load distribution in an inverted foot.

Introduction to the navicular, cuboid, and cuneiform bones, and their role in the foot's structure.

The significance of the tuberosity on the navicular and cuboid bones for palpation and identification.

The structure and importance of the metatarsals in the length and load-bearing function of the foot.

The unique anatomy of the big toe, including its two phalanges compared to other toes.

The presence of arches in the foot and their role in shock absorption and energy return during movement.

The function of the plantar aponeurosis and other connective tissues in maintaining the foot's arches.

The practical method of assessing foot arches by a wet footprint, and its implications for foot health.

A future look at the ligaments of the foot and their detailed examination for a comprehensive understanding.

Transcripts

in this video let's talk about the bones

of the foot or bones of the foot and

ankle let's have a bit of tibiofibular

in there as well right because that's

how all works get this nice big floppy

boney foot model we can use I've also

been 3d printing and toes come off this

one here to give to students to take

these away with them because it really

does help if you've got a physical thing

and you can look at all the bones you

can see what they articulate with you

can see the the bony prominences which

you can then palpate on your own feet

and that's a big earth but as you can

see if you can get a physical model

spend time with the physical models with

skeletons with bones when you're looking

at these and trying to learn these

structures right it's helps so what have

we got well the hand and the foot are

remarkably similar in that we have

collections of carpal bones hit the

wrist and we call these tarsal bones in

the foot so we have the carpus and the

Tarsus we have metatarsals which have we

have metacarpals in the hand we have

phalanges and so on so there are some

similarities and there are some

differences the hand is very dexterous

the foot is is a load-bearing structure

and they're both structured differently

because of that so what we've got up

here we've got the tibia and the fibula

and you can see that at the at the ankle

the fibula is not really a load-bearing

bone it's the tibia that's taking all

the load and transferring all the body

weight down into the foot down into the

ankle now look we can see the big toe

here the hallux so muscles that move it

o of the hallux alysus so this is the

big toe this is medial and we see

there's a lump here and there's a lump

here so two bony masses and you can

palpate these yourselves right now on

your ankles so the if this is the big

toe then this is the medial malleolus of

the tibia

and then this is the lateral malleolus

of the fibula and a number of structures

from the calf will curve around here

insert into the into the foot holding it

up and moving in that sort of thing but

do you see how how the the tibia and the

fibula together then of course they're

held together by ligaments and the

cinders mostly holding the two bones

together that those two bones are

forming the the open part of kind of the

squared off joint right so they're

forming a squared off space so the act

together they're now down in the ankle

we've got the heel this is the calcaneus

the heel bone the big muscles of Ghazni

meais and solaris insert into here so

your achilles tendon or your calcaneal

tendon inserts into here

and most of your bodyweight goes into

the ground through the calcaneus so the

calcaneus takes most of your weight the

tibia articulates with the tailless and

the tailless forms that hinge joint with

the ankle which also allows little bit

of side-to-side movement

tibia fibula calcaneus tailors and they

have a very specific very particular

shape to them right the builders are

still here banging this one here that

articulates with the tibia it forms this

kind of this the the squared bit of bone

that goes into the space the squared off

space made by the tibia and the fibula

so there's a but it's kind of

wedge-shaped and what this means is that

at the ankle we have plantar flexion and

dorsiflexion right so dorsiflexion

plantar flexion but we also have

inversion and e-version so you invert

your foot and you either at your foot

because of the wedge shape of the

tailor's bone that inversion e-version

is harder to do when dorsiflexed and

easier to do when plantar flex oh so as

u dorsiflex as you step forward the

wedge that tailors its into that space

better the wedge kind of wedges into it

which makes it harder to either tan

invert your foot but as you plan to flex

the wedge opens up there's more space

either side between the bone and the

space between the tibia and the fibula

which means that is easier to invert an

eva at your foot and many injuries of

the foot are caused by inversion and

e-version there are a whole bunch of

ligaments around here which attach these

bones to the the bones of the ankle and

support the ankle named after the bones

they attach to and those ligaments

commonly get sprained it's very painful

takes a long time to recover from and

it's much more likely that those sprains

will occur when plantar flexed because

this this bony joint is is more mobile

is weaker so watch out for that with

inversion because all of these things

are held tightly together the fibia can

also a fracture the hair should leave

that for another video really shouldn't

Lee and also other bones along here

which we'll mention in a moment the

metatarsals they're also more likely to

be fractured when landed on an inverted

foot because the load then goes through

the wrong place it goes through the

metatarsal instead of the calcaneus now

anterior to the talus we find the

navicular here navicular Navy like so if

you take this bone out it looks like the

curved hull of a ship that's a navicular

bone there and then we have cuboid bone

name because it's cuboid shaped

and we have the three cuneiforms now the

digits are numbered one two three four

and five right so the first digit is the

hallux is the big big toe so of the

cuneiforms or cuneiform bones but also

one two and three so from the the

tailless we have a navicular cuneiform

one clear form two cuneiform three and

then laterally we have this cuboid bone

here there is a tuberosity on the

navicular bone and see how this project

so you will be able to palpate this on

your own foot so you can find your

navicular and likewise you see this

tuberosity here as well there's a

tuberosity on the cuboid bone so you

should be able to palpate that on your

foot as well if you can palpate that

that means you can find your cuboid bone

and of course as we move anteriorly we

have one two three four five we have

these metatarsals making up much of the

length of the foot and look how large

that first metatarsal is that first

metatarsal bone is huge it's really

really big the fifth metatarsal is is

the most commonly fractured metatarsal

and as I said it's from landing on an

inverted foot the weight goes through

the metatarsal and you see how it also

has this G prosity

it here as well so you can palpate this

tuberosity this is normal I fractured my

fifth metatarsal and I had an extra lump

and a big hematoma off the bone

fractured and it

you often kind of get rid of a spiraling

fracture through there as the foot is

inverted you land on it awkwardly and

and then from the metatarsals anteriorly

we have the phalanges and don't forget

of course we have proximal middle and

distal phalanges for each of the toes

except for the hallux except for the big

toe which only has two phalanges just

like the thumb only has two phalanges

right

[Music]

now the foot is shaped in such a way

that it has a number of arches there are

three arches in the foot in fact we have

this medial longitudinal arch and the

medial longitudinal arch is the highest

arch is probably the most important arch

and it's immediately and it runs longer

to Denali and then we have a lateral

longitudinal arch which is a little bit

lower and then there's a transverse arch

which is formed by these bones here so

the cuboid uniform method tarsal bones

are forming an arch under there this

transverse arch and these arches are

held up by the plantar aponeurosis which

runs lengthways and by a bunch of other

connective tissues and muscles running

around which help hold the arch up as

well as the shapes of the bones

themselves the importance of the arch is

that as you walk or run you you load the

foot the joints your body with weight

with force

every time you strike the ground now if

you can slow the rate at which that

force is transferred across the foot and

into the ground then you reduce the

shock of that load so you reduce the the

shocks or other structures in the body

so so one function of the artists is

that as you land the connective tissues

holding the arches up stretch as the

load is applied to them so the weight is

the force is dissipated over time

through those connective tissue

structures then through the foot and

then into the ground all right so it's

um it's a shock absorbing mechanism but

also there's a measure of energy return

so as these connective tissue structures

get loaded and get stretched as you step

off some of that energy is returned into

your foot and there are other mechanisms

of mechanisms as well nickel is tender

than the cars and all sorts of things

but the arches are like shock absorption

and about efficiency of locomotion so

the arches are very important you can

look at your

Oh notches just by with a bare foot make

your foot wet step on a bit of paper and

look at the shape you leave and if you

have a very flat foot if you have very

low arches more of your foot will be in

contact with the paper but if you have

high healthy strong arches then you'll

only see you know the heel the balls

you'd be foot and the lateral foot

leaving a mark on the paper and your

toes and what have you and where you

have a nice high medial longitudinal

arch there'll be no contact with the

paper okay so the bones of the foot and

see if you can recognize these bones on

x-ray from different perspectives but we

have the tibia the big load-bearing bone

the fibula together they're forming the

upper part of the joint they're forming

the space into which the tailless fits

so the tailor's goes like this

and they allow the hinging movement of

plantar flexion and dorsiflexion

and then we have the calcaneus the heel

bone that you're standing on most of

weight goes through its the tailor's

that articulates with the tibia then the

tailor's articulates with the calcaneus

and then we have navicular cuboid one

two three cuneiforms metatarsals and a

whole bunch of phalanges the foot

straightforward important all right so

in the future we should probably look at

the the ligaments of the foot and how

some of these is held together by how

much detail do we go into okay right

bone to the foot