The Tibia

Summary

This educational video script explores the anatomy of the tibia and fibula, focusing on their roles in the human leg. It details the tibia's function as the weight-bearing bone, connecting the foot to the knee, and the fibula's role as a muscle attachment site. The script delves into specific bony landmarks, such as the tibial tuberosity and Gerdy's tubercle, and explains how muscles and ligaments interact with these bones, particularly around the knee and ankle joints. It also touches on the potential for injury and the importance of these bones in movement and stability.

Takeaways

• 🦿 The tibia and fibula are the two primary bones of the lower leg, with the tibia being the larger and more weight-bearing bone.
• 📐 The tibia has a triangular cross-section and is palpable as the 'shin bone', which is a key landmark for muscle attachment sites.
• 🔗 The fibula is considered more of an attachment point for muscles and is a smaller bone located laterally to the tibia.
• 🦴 The tibia articulates with the femur at the knee and with the ankle joint, playing a crucial role in weight distribution and movement.
• 🏞 The tibial plateau is a flat surface that articulates with the femur, forming part of the knee joint.
• 💪 The tibial tuberosity is a prominent bony landmark where the patellar ligament attaches, indicating a significant muscle attachment site.
• 🏃‍♂️ Gerdy's tubercle, located on the lateral side of the tibia, is where the iliotibial band attaches, important for knee joint stabilization.
• 🦵 The posterior tibia features the soleal line, indicating attachment sites for muscles such as tibialis posterior and flexor digitorum longus.
• 🤸‍♂️ The distal tibia includes the medial malleolus, a palpable bony prominence that forms part of the ankle joint.
• 🔗 The distal tibiofibular joint is a syndesmosis, a fibrous joint designed for stability and minimal movement, essential for ankle function.
• 🦿 The interosseous membrane connects the tibia and fibula, separating the leg into anterior and posterior compartments with distinct muscle groups and functions.

Q & A

What are the two primary bones in the lower leg?

The two primary bones in the lower leg are the tibia and the fibula.

What is the tibia commonly known as?

The tibia is commonly known as the shin bone.

How does the shape of the tibia's cross-section contribute to muscle attachment?

The tibia's cross-section is triangular, providing a ridge and flat surfaces for muscle attachment on either side.

What is the function of the fibula in the lower leg?

The fibula serves as an attachment point for muscles and is considered a remnant of an earlier stage in bone evolution, playing a supportive role to the tibia.

What is the tibial plateau?

The tibial plateau is the flat surface on the tibia where the femur sits and rolls against, covered in articular cartilage.

What is the tibial tuberosity and its significance?

The tibial tuberosity is a prominent bony lump on the anterior side of the tibia, where the patellar tendon attaches, serving as a major muscle attachment site.

What is the significance of Gerdy's tubercle in runners?

Gerdy's tubercle is where the iliotibial tract attaches to the tibia, playing a role in stabilizing the knee joint and potentially causing knee pain if the ITB becomes tight.

What is the role of the interosseous membrane between the tibia and fibula?

The interosseous membrane is a thick fibrous membrane that links the tibia and fibula along their length, providing stability and separating the leg into anterior and posterior compartments.

What is the distal tibiofibular joint and its function?

The distal tibiofibular joint is a syndesmosis, a fibrous joint with little to no movement, that helps form the socket shape for the talus bone at the ankle.

What is the medial malleolus and its importance in the ankle?

The medial malleolus is the bony protrusion on the medial side of the ankle, part of the tibia, which forms the hinge joint with the talus and is palpable on physical examination.

What does the term 'condyle' refer to in bone anatomy?

Condyle refers to a knuckle-like rounded projection on bones, often found at joints, such as the tibial condyles on the tibia.

Outlines

00:00

🦿 Anatomy of the Tibia and Fibula

This paragraph introduces the bones of the lower leg, focusing on the fibula, and explains how to identify its location and articulations. It describes the palpable features of the tibia, including its triangular cross-section and the muscles that attach to it. The script also discusses the roles of the tibia and fibula in supporting body weight and muscle attachment, respectively, and touches on the etymology of their names.

05:01

🏃‍♂️ The Tibia's Role in Movement and Muscle Attachments

The second paragraph delves into the anatomy of the tibia, highlighting its importance as the second largest bone in the body for weight transfer. It describes the tibial plateau, tibial tuberosity, and Gerdy's tubercle, explaining their roles in muscle attachment and potential impact on knee stability. The paragraph also discusses the iliotibial band and its connection to the tibia, which is crucial for runners and can cause knee pain if tight.

10:05

🦴 Detailed Examination of the Proximal and Distal Tibia

This section provides an in-depth look at the proximal and distal ends of the tibia, discussing the condyles, intercondylar eminence, and the attachments of various muscles and ligaments. It explains the synovial joint between the tibia and fibula and the interosseous membrane that connects them. The paragraph also covers the distal tibia's role in forming the ankle joint and the importance of the medial and lateral malleoli.

15:07

👣 The Medial and Lateral Malleoli of the Ankle

The final paragraph concludes the discussion on the tibia by focusing on its distal end, particularly the medial malleolus, which is palpable and forms the medial side of the ankle joint. It describes the medial malleolus's large flat articular surface and its role in weight-bearing. The paragraph also contrasts the medial malleolus with the lateral malleolus of the fibula, which forms the lateral side of the ankle joint, and briefly mentions the groove for the tendon of tibialis posterior.

Keywords

💡Tibia

The tibia, also known as the shin bone, is the second largest and most superficial bone in the human body. It plays a crucial role in bearing the body's weight and transferring it from the foot to the knee and the rest of the body. In the script, the tibia is described as having a triangular cross-section with a prominent ridge that can be felt on the shin, and it articulates with the fibula and the femur at different points.

💡Fibula

The fibula is a long bone located lateral to the tibia in the lower leg. It is smaller and serves more as an attachment point for muscles rather than bearing weight. The script mentions the fibula's head, which articulates with the tibia, and its distal end, which is part of the ankle joint.

💡Articulation

Articulation refers to the way bones meet and connect at joints in the body. The script discusses various points of articulation between the tibia and fibula, such as the proximal tibiofibular joint and the distal tibiofibular joint, which are essential for the movement and stability of the leg.

💡Muscle Attachment

Muscle attachment points are areas on bones where muscles connect, allowing for movement and support. The script describes how the tibia has 'lumpy bumpy bits' that serve as attachment sites for various muscles, emphasizing the bone's role in muscle function.

💡Tibial Tuberosity

The tibial tuberosity is a bony prominence on the anterior surface of the tibia, just distal to the condyles. It is the attachment site for the patellar ligament, which connects the kneecap (patella) to the tibia. The script mentions it as a palpable landmark on the shin.

💡Gerdy's Tubercle

Gerdy's tubercle, also known as the anterolateral tibial tubercle, is a bony landmark on the lateral side of the tibia. It is the attachment site for the iliotibial tract, a thick band of fascia that helps stabilize the knee. The script highlights its importance for runners, as tightness in the iliotibial tract can cause knee pain.

💡Interosseous Membrane

The interosseous membrane is a fibrous sheet that connects the tibia and fibula along their length, with a hole at the top and bottom for certain structures to pass through. The script explains that this membrane separates the leg into anterior and posterior compartments, which is important for understanding muscle and nerve distribution.

💡Medial Malleolus

The medial malleolus is the prominent bony protrusion on the medial side of the ankle, formed by the distal end of the tibia. It is a palpable structure that can be felt on the inner side of the ankle and is part of the ankle joint, providing stability and forming the medial side of the joint.

💡Ligament

Ligaments are fibrous structures that connect bones to each other, providing stability to joints. The script discusses the role of ligaments in reinforcing the tibiofibular joint, preventing movement between the tibia and fibula, and their importance in maintaining joint integrity.

💡Syndesmosis

A syndesmosis is a type of fibrous joint where bones are held together by fibrous tissue, such as ligaments or an interosseous membrane. The script mentions the distal tibiofibular joint as an example of a syndesmosis, which is important for the stability of the ankle joint.

💡Anterior and Posterior Compartments

The anterior and posterior compartments refer to the two distinct muscle groups in the lower leg, separated by the interosseous membrane. The script explains that these compartments have separate blood supplies and nerve innervations, which is crucial for understanding muscle function and potential medical conditions.

Highlights

The tibia and fibula are two bones in the lower leg that articulate with each other and with other bones.

The tibia is the shin bone and is palpable due to its superficial and subcutaneous nature.

The fibula's role is primarily as an attachment for muscles and is considered a remnant of early human anatomy.

The tibia is the second largest bone in the body, responsible for transferring body weight from the foot to the knee.

The tibia has a triangular cross-section with a ridge that can be felt on the shin.

The fibula head articulates with the tibia, contributing to the stability of the knee joint.

The tibial tuberosity is a prominent bony lump where the patellar ligament attaches.

Gerdy's tubercle is a point of interest for runners as it is where the iliotibial tract attaches to the tibia.

The posterior tibia features the soleal line, indicating the attachment of muscles such as tibialis posterior and flexor digitorum longus.

The distal tibia forms the medial malleolus, a palpable bony prominence on the inner ankle.

The fibula and tibia are connected by the interosseous membrane, dividing the leg into anterior and posterior compartments.

The distal tibiofibular joint is a syndesmosis, a fibrous joint with minimal movement, essential for ankle stability.

The medial malleolus of the tibia has a large flat articular surface for the ankle's hinge joint.

The tibia's shape and structure are crucial for weight-bearing and muscle attachment.

Anatomical knowledge of the tibia and fibula is essential for understanding leg function and potential injuries.

The tibia's proximal and distal ends articulate with the femur and ankle bones, respectively, forming critical joints.

The tibia's intercondylar eminence locks into the femur, contributing to knee joint stability.

The tibia's distal end features the fibula notch and medial malleolus, integral to ankle joint formation.

Transcripts

[Music]

you talk about the tibia fine well we

can talk about the tibia I've got a

fibula because these two articulate what

we'll do is we'll look at the fibula

work out where it is I reckon you know

where it is what it articulates with and

we'll look at the lumpy bumpy bits on it

and there might be a very good nod to

some muscles that attach the lumpy bumpy

bits right it's a left one all right one

[Music]

the left one

okay must stand you on the table so you

see your legs I'll try and do in under

four hours should we where is it well of

course it's here all right that's it

this is a just keep the size the same to

keep the confusion down to a minimum

right you're very expensive to pull off

I can see them all right so hey this

works so here's the tibia here's the

knee here's the ankle the tibia is here

and the fibula bone is there so you can

you can palpate your your tibia it's

it's your shin bone which shows you how

superficial is how subcutaneous is you

can feel their own you've got this this

Ridge here if you look at the

cross-section of the bone here it's

actually triangular and what you're

feeling is this is the point of the

triangle as your shin and there is

muscle to either side but you can feel

see I'm doing it this is a well this is

a left you can feel muscle on either

side of that shin bone so the other

thing to feel you can feel the tibia

this is lateral for me the other thing

you feel

so there's the knee there's the patella

he's not actually here you've got the

head of the fibula now this is my right

leg here's the left leg here look so

this is the this is what we were

palpating the anterior part of the tibia

here so you can imagine that we've got

these nice flat surfaces for muscles to

attach to which is why we've got this

triangular shape and then here's the

fibula laterally and there's the head of

the fibula there so we've got an

articulate articulation between the

tibia and the fibula here and at the

distal end we've got an articulation

with the femur here at the NIEM we've

talked about the bones and ligaments of

the knee joint and then we've got

another articulation down here with the

ankle so we need to consider each of

those in the shapes of the bone and how

they how they work to do those things

right but the big thing here is the big

thing here is that the tibia is the big

thing so you can see that the tibia it's

actually the second largest bone in the

body it's a really really big bone and

the reason is because it's transferring

all of your weight along its length

so the tibia is the big bone the tibia

is carrying the load between the foot

and the knee and the rest of the body

whereas the fibula is a little we defer

a little we debone sitting on the side

the term is more of an attachment for

muscles and that sort of thing in kind

of a remnant of the way in which were

organized anyway tibia there was a Greek

instrument called a tip something that

was it called a tibia or something like

it's hit like I flew you know like a

pipe like a recorder if you were of my

agent

remember primary school but you know

it's like a wind instrument or a reed

instrument that's what a tibia is that's

what the tibia is named after the fibula

is named after a word for pin a Greek

word for pin laughing with a pin

they are fibula and peroneal you know

said so anyone with tibia right stay on

stay on topic let's start the proximal

end and we'll work our way distally

so remember this is a left this is a

left tibia right so this is lateral this

is medial we've got two condyles we have

a lateral condyle and a medial condyle

and in between the two we've got a

couple of intercondylar cubicles lateral

and medial intercondylar cubicles and

together they form the intercondylar

eminence

so the intercondylar eminence then is a

is like a ridge between the two condyles

the purpose of which is to lock into the

we've done let's say we've done the knee

joint even worse than the proximal femur

which want to look at those but the the

ephemera and the femur the femur has

also got two condyles and it's got a

groove and intercondylar fossa within it

so so these intercondylar tubercles this

intercondylar eminence is going to you

know fit with the the femur and what we

see what about these two tibial condyles

is there it's forming a pretty flat

surface I mean this is just a bone

imagine it covered in articular

cartilage as well and that's why this

gets called the tibial plateau it's like

you know it's a plateau it's a flat

thing that the the femur can then sit on

and roll against most obvious features

here are this lumpy bit here which yes

you can palpate on yourself there this

is the tibial tuberosity

so the tibial tuberosity is where the

patella the patellar tendon or patellar

ligament runs to so a quadriceps femoris

crosses the knee runs through the

patella and inserts at the tibial

tuberosity this is a very prominent bony

lump anteriorly just distal to the

condyles because because that's a really

really big muscles was a big attachment

so look it said that it's at the top of

that just at the top of that triangle

top of that Ridge there

by the way condyles condyle means

knuckle because it is it's like a

knuckle isn't it but it looks like a

knuckle so that's literally what contour

the condyle is now on the an interesting

thing for me as a runner is Gudi cubicle

or gerdes tubercle which is on the this

is on the lateral side and it's on my

the anterolateral part of the lateral

condyle so it also gets called very

unimaginative ly the anterolateral

tibial tubercle her also known as

Goody's tubercle the reason that's

interesting to me the Run is because

that's where the iliotibial tract

attaches all can we see that on here so

the the leg is covered with a stocking

of fashion a fattier later it has a

thickening here laterally which is

remained on this model the rest of the

fash has been taken away and this is the

iliotibial band all the iliotibial tract

or your ITB it does a number of things

one of the things it does is it helps

stabilize the knee joints and look

everyone's laterally to the knee and you

can see that okay so there's the patella

there's the tibial tuberosity here's the

the bare subcutaneous tibia here and

here's actual at hand it's the left 4 as

well so the the head of the fibula is

there and look these fibers are just

running to this point here just a little

bit anterior to where we would find the

head of the fibula on the actor

anterolateral part of the of the tibial

condyle there so everyone is it everyone

is you make everything like tight and

short every now and then everything gets

painful list if this gets tight it pulls

on the knee too much gives you a bit of

knee pain so you get your phone's long

run and try and sort it out anyway

so that's something I like

so tibial tuberosity goodies tubercle

then if we if we roll around posterior

Lee we can see can you see the salal

line here there's a ridge here and it's

kind of twisting around and that cell

line indicates where so Laius is given

attached and bits of tibialis posterior

and flexor digitorum longus which are in

the posterior these are all muscles in

here right so if we take off what I got

to take everything off you know I've

done the muscle somewhere else don't

look at that one gastrocnemius take that

off underneath there is so Laius

so you Caecilius and then tibialis

posterior the other guys do you see how

my videos end up being really really

long because there's just so much to

talk about so if I stick the fibula back

on so you can see lateral versus medial

if we spin this around you can see that

that's a lay-oh line starts laterally

close to the fibula head and then runs

medially around here so that's that

curvy bit we're talking about and while

we're on the posterior proximal tibia I

can see so this is the medial side hit

natural medium I can see there's a

little little depression there we've got

the two hamstrings on the medial side

semimembranosus and semitendinosus are

going to come in to the tibia here

semimembranosus is the deeper one

there's this little shape here is formed

by the attachment of semimembranosus to

the tibia there that's exciting

insertion way more detail than anybody

knows needs to know or cares about

alright and what is useful well here's

the lateral condyle

here's the fibula attaching to it so can

you see that on the on the on the

lateral condyle of the tibia on the

posterior part we've got this facet here

for the fibula to attach to

now the fibula and the tibia are

attached at a number of points as this

this would be the proximal tibia fibula

joint and there's also the distal one

down there and then they're joined by um

an interosseous membrane like a thick

fibrous membrane linking the two bones

along their entire length with a hole at

the top and I'll hold the bottom for a

couple of structures to pass through now

these two bones are not supposed to

articulate around each other they're

supposed to be fixed in place bear in

mind that this proximal joint is a

synovial joint is a synovial plane joint

so the two bones could potentially slide

over one another so it's an articular

joint with articular cartilage a

synovial couch it was proper synovial

joint right it is reinforced anteriorly

and posteriorly by ligaments so the

ligaments I guess hold it in place and

prevent movement but because that joint

exists because it's an articular

cartilage you can imagine the disease is

affecting articular cartilages could

affect this joint here and of course so

with enough trauma you could separate

that Julianne as well so be mindful of

that so I think you just you know gets

called like it's a facet for the fibular

head here on the lateral condyle of the

tibia approximately that's about it for

the proximal tibia and as I said it's

been work our way down is thickest

approximately and gets thinner distally

or inferiorly it's a smaller bone down

here it has a triangular cross-section

with this sharpish leading edge giving

nice flat surfaces for muscle

attachments so then it's been run down

distally most of all again is this

is this distal shape here the distal

tibiofibular ligament and this end is as

syndesmosis it's a fibrous joints not as

soon over your joint an articular joint

it's it's very much a fixture here I see

these sutures between the bones of the

skull are also fibrous joints these you

know these are joints that are designed

or intended not to move and when we get

down to the ankle that's really

important because we see that the fibula

and the tibia are working together to

form this this socket shape for the

tailor's bone to form the hinge joint of

the ankle so this is a syndesmosis of

fibrous joint a tough joint and this

should have pretty much no movement at

all that's the distal tibiofibular joint

the thing that's most is then since in

Nesbit's the interosseous membrane

running between the tibia and the fibula

down here is actually going to separate

the leg into an anterior and a posterior

compartment that's what we see here so

we've got all these muscles in the you

know anterior so that - the tibia and

all of these muscles posteriors the

tibia they're in two separate

compartments with essentially separate

blood supplies and separate nervous

innovation very helpful the medical

students who are trying to remember

where things are and where things go and

what they do right you know all the

muscles of the anterior compartment to

do all the offers the posterior

department did you know they're similar

functionally and anyway going off topic

again all right so what we got at the

distal tibia then well we've got the

fibula notch on one side so that is the

shape here this receiving the distal

fibula there are of course tibiofibular

ligament tying all that together as well

that's the fibula notch and then the big

thing is we've got the medial malleolus

and medial malleolus again

you can palpate on your own ankle right

this is what your ankle feels like the

big lumpy bits on your ankle the bony

bits of your ankle the medial malleolus

is your tibia and the lateral malleolus

is your fibula so those are the bony

bits that you can feel of your ankle if

we look posterior Lee

there's the medial malleolus it tends to

have it's got a bit of one has a groove

in it and that's the groove for the

tendon of tibialis posterior we can

around their tibia medial malleolus

hikin tibialis posterior can around here

so there's often a little bit of a

groove in the bone posterior to the

nujol malleolus which is nice and that

got loads of cool stuff going around

there all right so the medial malleolus

then is you can see you've got this

large flat articular surface this is

articulating with the tailor's alright

so this is again a synovial joint a

proper to know if you'll join with

articular cartilage covering a mall have

you this is the the hinge joint of your

ankle the medial malleolus is then

binding the medial side and the lateral

malleolus of the fibula is bound in the

lateral side and forming the shape of

that joined together but it's the tibia

that has the large flat articular

surface because it's the tibia that's

taking the weight through the ankle

passing it up to the knee up the thigh

of the hip and it's taking the weight of

your body onto your foot right and

that's it right that thighs stays the

tibia those are the bits of the tibia

hey go I was that the the anatomy of the

shin bone if you are a shin bone in the

exam you are not going to get mark tibia

all right see you guys next time

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you

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