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WHISPER: Ouchtastic!

I've been thinking we should create another skeleton to keep

Billy Bones company.

He could do with someone else bony to talk to.

Brilliant idea.

So what do we need to make the perfect skeleton buddy?

Around 206 bones.

Righto.

I'll go raid the kitchen cupboards.What for?!

Growth plates, we need them to grow bones.

Duh! You won't find them there, Xand.

Don't you mean the growth plates inside your body?

Oh, yeah.

Our first Ouchtastic! skeleton question is in.

How are my bones made?

Great question!

I think the answer to this lies in our lab!

Xand, to understand this, we need a bone.

One human bone coming up.

Chris, we've got a few in here.

What size are you looking for?

I don't know something about that long. A humerus, maybe.

Come on out, Humerus, come on. Come with me. That's good.

Now stand there, next to Dr Chris.

Right, Dr Chris, meet Humerus.

Humerus, meet Dr Chris.

Xand, this isn't Humerus. This is Esther.

Hi, Esther. Hi, Chris.

Esther has broken her collarbone.

From the collarbone, we can now see the humerus.

That's the arm bone.

At the top of the humerus is the growth plate.

It's made of a soft, squishy material,

and there are cells there that produce cartilage.

The cartilage then hardens up

and turns into bone that's added in layers,

and that is how your bones grow.

Chris and my bones are not still growing,

but Esther's are and so are yours.

Once you get to be an adult, your growth plates close up.

This is why, when you're a kid, you have more bones than an adult.

You start with around 270,

and then as they grow and the plates close up,

you're left with around 206.

Esther, thank you very much for coming into our lab

and showing us your amazing arm X-ray.

All right, Humerus, back to the cupboard. Go on, off you go.

Do you know, Chris? I've been thinking,

why does it take so long to grow?

I mean, waiting to get taller is just so boring.

Well, that is a great question, Xand.

Let's find out.

To show you why your bones take years to grow and make you taller...

Xand and I are going to make some bones,

one femur each to be precise.

The leg bone.

We'll both be using this plaster putty

to represent the cartilage cells in the growth plate.

It's not real bone, but it will set hard

like the cartilage in your body.

I'm going to be making my bone the natural way.

I'm going to be making my bone the much more fun and quick way.

I'm calling it, "The all-in-one, one-stop shop

"overnight bone-making method."

Catchy. I thought so.

OK, Chris, are you ready?

I am ready.

WHISTLE BLOWS

I'm chucking all mine in this plastic tube

to make the bone in one go.

I'll be done in no time!

No plastic tubes for me, Xand.

I'm trying to be as true to how our bodies build bones

in real life as I can,

so I'm drying each layer,

making it set firm before adding another.

Well, I must say, my one-stop bone shop overnight method

is really working out well.

Getting a bit bored with how long this is taking you.

I'm going to go and find something else to do.

I can't believe Xand thinks his bone is finished.

This takes time!

So this is a bit more like what happens in your body.

The growth plate lays soft cartilage

down on the top of the bone shaft,

and that cartilage then gradually is turned into bone

and becomes hard.

Oh, come on, Chris! We've got to finish here.

I mean, that's growing about as fast as real humans!

Xand, that is the whole point.

I may not have made much, but this...

..is almost as strong as real bone.

Are you honestly telling me that this femur that you have made

has the required structural stability?

I absolutely am.

Mm...

Oh, no!

Oh, no. It's all going wrong!

Xand's bone is all floppy and hasn't set.

If this was a real person, it would be a very weak femur,

and they'd be flopping about on the ground.

What a disaster.

So what we've learned is we can't rush this bone growing process.

Definitely not!

We need to give Billy's new skeleton pal time to grow strong bones.

Exactly.

Why are my bones so strong?

For this question, we did a super duper experiment in the lab.

Just watch out for my slimy friends!

Ugh!

How many times do I have to tell Xand not to put giant snails

on my clipboard?

In fact, there are giant snails all over the lab.

Xand! This is meant to be a snail-free lab!

I'm preparing for our bone experiment,

and to do it, I thought I'd talk to creatures

with different kinds of skeleton.

Stacy here has got her skeleton on the outside of her body,

called an... Exoskeleton.

Right, and what have you actually learned from talking to the snail?

Stacy's exoskeleton is a little bit like our bony skeletons.

It needs to be light enough that she can move.

But to support and protect her body, it also needs to be... Strong.

Well, that's just like human bones, and I have one here.

This bone is over 100 years old.

It's an adult human thighbone, or femur.

Like Stacy's shell, it's light.

But what is amazing about your femur

is that this lightweight piece of body kit

is one of the strongest bones in your body.

A femur can withstand huge weight pushing down on it.

Let's take a closer look to see how that's possible.

Now your bone gets its strength from its clever design.

This outer parts of the bone is hard like rock.

It's called cortical bone.

But if this thighbone were solid cortical bone,

it would be way too heavy. So let's have a look inside.

Because this bone isn't living, there's no bone marrow,

so you can see something else.

At both ends of this bone,

there's a fine lattice of thin strands of bone,

and this is called trabecular bone.

It's very light cos of all the space in there.

This is a similar kind of structure to the honeycomb in a bee's hive.

The honeycomb structure in your bones is what gives them

the strength to withstand weight pushing down on them.

I can show this to you, Chris, with some toilet roll.

Really? Here they are,

all arranged in a honeycomb structure.

Chris, on you get.

All right - on your head, be it.

What do you think will happen when Chris stands on them?

Wow! Look at that!

Xand's toilet roll collection is supporting my entire body weight.

Honeycomb is such a strong structure,

that your bones can carry a huge amount of weight.

And, in fact, gram for gram, bone is stronger than steel.

Stronger than steel?!

Well, that sounds like a challenge.

All right. Well, can you give me a hand down, and we can do it?

Come on.

There you go. Thank you. Upsy-daisy.

We want to know how much weight a femur can actually hold.

We need to put it to the test.

I've built a steel platform

that is being propped up by four cow femurs, or thighbones.

These bones, which are like yours, have the weight of the platform

pushing down on them, a very heavy 300kg!

And the bones are happily holding it.

So I think we need some heavier things

to really put them to the test.

Xand?! Take it away!

What's going on? We're going to find out if those femurs

can handle the weight of a van filled with heavy furniture,

and Mr Grumbles!

That's a massive 2,274 kilos.

And the bones are not buckling!

That is amazing.

And it's all thanks to the super strong, super light

structure of your bones.

So we've seen that your bones are strong and light,

but do you know this?

True or false?

The answer is..

..true, this is because bone is living tissue.

And we can see this with our next brilliant body.

Having strong leg bones that can support big weights

pushing down on them is vital for athletes

like gold medal-winning triple jumper Naomi Ogbeta.

She jumped an incredible 14.15 metres.

That's almost the length of one and a half buses!

Naomi, tell me what you love about the triple jump.

What I love about the triple jump is

that it literally feels like I'm flying.

It feels like I'm flying in slow motion.

Can you walk me through it, and show me how to do it? Yeah, sure. OK.

Stand on your strong leg.

Hop. Hop. Step. Step. Jump. Jump.

Great. OK!

OK, Xand, let's see what you're made of.

Ah!

Whoops! Better luck next time, Xand.

Ah!Good effort, Xand. Keep practising,

and you might get close to Naomi's 14 metres.

Having tried to do it, what's amazing

is the amount of pressure as you do that first hop,

landing on that leg.

I feel like the shock went all the way to the tip of my head.

That's why it's really important that I go to the gym

and make sure that I can lift twice my body weight,

so that I'm so used to feeling the impact of my body

landing with speed.

So your legs have to be able to handle a huge amount of force.

And we're going to put that to the test.

Here at Manchester Metropolitan University, Professor Neil Reeves

is going to give us a closer look at what's happening

when Naomi jumps.

So the forces involved in the triple jump are massive,

and in order to measure them,

in Neil's lab, what there is, is a pressure sensor in the ground,

and when Naomi lands with all her

body weight on that first foot in the hop,

that pressure sensor is going to tell us

how much force her body can generate.

So, here, you can see on the screen, the height of this arrow coming up.

That tells us how much the force is that's acting on the legs.

We've measured that, and that's actually over five times

your body weight.

So when you're landing at the end of just that hop,

that's like standing on one leg with four of you on your shoulders.

When you think of it like that, that does sound really heavy.

So this is obviously a much shorter run-up, a shorter hop.

If we were looking at Naomi in real competition circumstances,

how much force do you think would be going through her leg, then?

Up to 15 times body weight can go through the legs.

That's a massive amount of weight! Yeah. That's crazy. Wow.

Naomi's body can withstand those huge forces

as a result of her bones getting stronger through training.

As we've seen, the inside of your bones

are full of holes that look like honeycomb.

When you run or jump, stress is placed on the bone

each time you land.

This causes bone cells, called osteoclasts,

to rush to where the stress is,

and they start to make a protein called collagen.

And drop it between themselves, making the hole smaller.

The smaller the holes, the stronger your bone is

and the more force they can withstand.

The more Naomi jumps, the denser her leg bones will become.

And that's how her legs are able to withstand such massive forces

and why her body is so brilliant.

Now all I need to do is work on my triple jump.

Now, I think it was...a run, a hop... Ah!

Well, Billy, you'll be pleased to know that your new mate

now has a set of fully grown bones,

all nice and...strong. Yikes.

Sorry, Billy.Don't worry, Billy,

sometimes bones do break, but they can be fixed.

If bones are so strong, why do they break?

Well, it's all to do with the angle of impact.

This is a femur bone,

and as we've seen, they're designed to withstand enormous weights

along their length.

But if you hit it from the side, it's a different story.

Remember, the toilet rolls?

End to end, they're immensely strong,

but turn them on their side, and they crush easily.

Well, it's the same with your bones.

Now, Xand, what I want you to do

is to apply a moderate and precise force to the middle of that bone.

You got it? Absolutely. Stand aside, Chris,

while I do some science.

Ah! Mighty Xand and his bone-crushing hammer, Daisy.

This is an extreme version of a bone breaking.

Hardly anyone's bones break fully in half.

As you can see from these X-rays,

broken bones come in all shapes and sizes.

So when a bone breaks, how does it repair itself?

# If there's a bone to break, he'll break it

# If there's a knee to graze, he'll graze it

# If there's an ankle to sprain, he'll sprain it

# He's the unluckiest kid. #

Look out for that squirrel.

When you break a bone, it's called a fracture,

and it gets put into a plaster to keep it in place.

But underneath, the real fixing is done by you.

Wow.Your broken bone leaks blood,

and it contains special building blocks, including fibres

from proteins called collagen and cartilage.

They build a temporary bridge called a callous,

and it stays in place for about three weeks.

Then a specialist team called the osteoblasts move in.

These are cells that make tiny bits of bone that set like cement.

After a few weeks, your bones have repaired themselves,

your cast will be off and you're as good as new.

Just watch out for the squirrels!

Uh-oh. Oh, dear.

# He's the unluckiest kid. #

This is how most broken bones are fixed.

But sometimes they need more help.

Just like ten-year-old Casper's troubled tibia.

I broke my leg about a year ago, but recently it just got really sore.

This morning, it got worse, and I ended up here.

Looks like that leg's in limbo.

How did it happen?

One year earlier, it was a beautiful, sunny day.

Beautiful!

Birds were tweeting. Tweet, tweet!

Flowers were... Dancing!

Uh, yes, OK, and Casper was playing in the garden

with his friend, Magnus.

Ooh, what were they playing?

They were running around, blasting foam darts. Pow, pow, pow!

Sounds like fun.

It was, until Casper tripped over a tree root and broke his leg.

TOGETHER: Ouch!

A year on, and that leg is still causing problems.

And now it's started to spring up stuff

and white chunks of gravely stuff.

That's no laughing matter, Casper.

Best get that grim limb in to see Dr Ashok Lal Ramavath.

So we need to examine the wound and see how it is. It looks horrendous.

That's right, Mum. Gross alert coming up!

When Casper first broke his leg, he had an operation.

And doctors discovered he had a tumour, which they removed.

Can you wiggle your toes for me, please?

To strengthen his leg bone, they inserted a metal plate.

What, like this? Yep. That's the one.

Most of the time, your bones are able to rebuild themselves,

but if you have a tricky break like Casper,

docs may need to give your body a jump-start with a bone graft.

This is a surgical procedure

where they add a special substance that's like moulding clay.

This copies your body's natural healing process

by making scaffolding and encouraging new bone cells to grow.

Sometimes, like in Casper's case, the material can leak.

It's nothing to be overly concerned about,

but there could be an infection.

So the doctor orders bloods to be taken. One, two, three, go.

And X-rays.

OK, brilliant, that's great. We're all finished.

If there's an infection, Casper may have to have surgery to sort it out.

This is the X-ray picture on Casper.

And the white substance in the wound

is coming out, which is not good for the bone.

The good news for Casper is that his leg isn't infected,

but the bad news is that the leaking bone graft will need an operation

to sort it out.

Best leg it to surgery sharpish to be seen by surgeon Chris Prior.

Casper has had a general anaesthetic,

so he won't feel a thing.

Once surgeon Chris has cleaned the wound,

he has an ingenious idea to help that leg heal.

We've put a special dressing over the top of the wound,

it attaches to a machine

that acts like a vacuum cleaner.

It sucks the air out from it.

So because the air has been sucked out,

it closes the edges of the wound together,

so that it will heal in a nice position.

With that pump now attached to Casper's leg,

the wound has a much better chance of healing quickly.

Casper will keep the special pump attached to his leg for five days

to help heal it.

Bye, Casper!

Uh, Xand, what are you going to do with that hammer?

Put our skeleton's nice, strong bones together.Xand!

I think you've forgotten the other important role of a skeleton.

Oh, of course, a skeleton needs to be able to move!

And for that we need...

TOGETHER: Joints!

TOGETHER: How do my joints work?

You have around 360 joints in your body.

But which is the most flexible?

Is it A, ankle,

B, hip,

or C, shoulder?

The answer is C, shoulder.

To show you how it works, we had a very special guest in the lab.

Sample, come out of the cupboard!

Xand, this isn't a sample, this is Bonetics,

He's one of the world's best flexing dancers,

and hundreds of millions of people have watched him perform.

Hi, Bonetics. Great to see you. Great to see you.

Stop chit-chatting, you two, and get on with the science.

Come on, do the shoulder stuff.

Wow!

It's amazing, isn't it?

That is completely amazing.

How are you doing that?

Loads of stretching and practice.

But you should never try this at home.

Whether or not you're as flexible as Bonetics, the shoulder joint

is still the most flexible joint in all of our bodies.

Bonetics, thank you so much for coming today. Thank you, Chris.

Get back in the cupboard!

Time to take a closer look at that amazing shoulder joint.

Stand by for a gross alert!

This is a shoulder from a pig, and it's a lot like your shoulder.

You can see here the shoulder blade, also called the scapula.

And this is the humerus.

There are muscles and tendons all around it.

And those can pull on it so that it can move

in lots of directions.

You can see how that's able to happen

if we look inside, because it's called a ball-and-socket joint.

Look at how shiny it is.

It's extremely smooth so that it can move easily

in lots of different directions.

That's the ball, the top of the humerus, and that is the socket.

Chris, turn around.

Imagine this is your shoulder.

Your ball-and-socket joint is so flexible it can rotate

all the way up here.

But your shoulder's flexibility is even greater,

and that's because your scapula can move too, like this.

And that is what gives your shoulder so much flexibility,

the combination of that ball-and-socket joint and the fact

that the scapula can move freely.

But the shoulder joint isn't the only ball-and-socket joint

in your body. You also have them in your hips.

But the hip joints are less mobile because the ball is set more deeply

into the socket.

And to show you why you can do more with your arms than your legs,

we're headed to the Cupboard-of-Everything.

Wait for me! Where are we going, Chris?

Welcome to Ruffts, the dog show with a difference.

It's dog versus human

in an experiment to show you how the amazing range of movement

in your shoulders makes humans unique.

Representing the canine species is Dougie,

award-winning agility dog.

And representing your species is...

..Xand.

Are you ready? Three, two, one.

Go!

Dougie makes light work of the seesaw,

his full leg joints giving him superb stability,

but Xand isn't far behind.

His flexible shoulder joints allow him to extend his arms,

giving him excellent balance.

So that's five points each.

Onto the second part of the course.

This event is the monkey bars.

So, Xand here is swinging gracefully from bar to bar,

he's rotating that ball of the humerus bone

in the socket of the scapula,

but he's also twisted the scapula right round

so his arm is above his head.

Dougie's leg joints don't have the flexibility of Xand's shoulders.

He can't reach overhead,

so he's showing off on another obstacle.

Good effort, Dougie, but it's only four points

for not completing the obstacle as required.

Xand gets five points.

Next, it's the tunnels,

and Xand's is a bit different to Dougie's.

Well, I'm very curious to know what we're going to learn about the

shoulder from doing this, Chris.

This is just about getting you muddy.

It's the big finale, and there's just one point between them.

Xand's using his flexible and strong shoulder joints

to pull himself over the wall.

But Dougie's leg joints just don't have the same

strength or flexibility.

He just can't get over the big wall, so,

he chooses a less steep ramp, which he races over to cross

the line ahead of Xand.

That's only four points, but he gets a bonus for cuteness.

Well done, Xand, you are the Ruffts Champion! Woohoo!

And it's all thanks to those amazingly strong,

flexible and mobile human shoulders of yours.

WHISPER: Ouchtastic!

Meet our new bony jointed friend, Billymena.

Oh, Billy looks pleased!

Well, they'll be able to have lots of fun together now.

Xand, you didn't forget the ligaments, did you?

Whoops, sorry.

How are my joints held together?

Well, it's all thanks to ligaments!

Your ligaments are white bands

of an elastic protein called collagen.

And it's the way that these fibres are arranged in the ligament

that gives them their strength.

Now, if I take one piece of wool,

imagine that this is a strand of collagen.

If I pull on it, I can break it pretty easily.

If I take lots of strands of wool and twist them together,

a bit like a rope,

what you'll find is that it's much stronger.

In fact, come on, a really good pull.

Ugh!

THEY GRUNT

There you go. You see? You can't break it.

The wool is much stronger because the force of being pulled

is shared by all of the strands instead of just one,

and your ligaments are actually made in the same way

with strands of collagen.

Now, it isn't just the strength of your ligaments that's important.

They're also arranged in a special way around every joint

to keep the bones tightly together.

And to understand this better,

we're going to take a look at some real ligaments. Ooh!

Here comes a gross alert!

This is the leg of a cow.

This is the cow's knee joint, and it's a lot like yours.

If I bend the knee, right there,

that's the anterior cruciate ligament.

The knee's a really special joint

because it's got ligaments inside it.

If we look at the back, that fibrous band there,

that's the posterior cruciate ligament.

So these two ligaments cross over in the knee.

That means that the femur and the tibia never come apart,

because this ligament formation is so strong.

In order to see how strong, we're going to have to go outside.

That's because... We're going to use a tug-of-war.

Whoa! I love a tug-of-war.

Now, this is our cow's knee.

Now, this bone here is the femur.

It's attached to a rope that's going to be pulled by Team Femur.

THEY CHEER

This bone is the tibia, and it will be pulled by Team Tibia.

THEY CHEER

We're going to gradually add

more of these super strong rugby players,

who will pull on the rope until the ligaments snap.

Rawr!

HE CLEARS HIS THROAT

OK. Take up the strain, and...

HEAVE! Heave!

Come on! Come on, Tibia! Come on!

Let's add one more person from each team. Next person up!

And heave! Heave!

Remember, the combined weight of each player is putting the ligaments

under incredible strain,

and it's not budging!

Now we've got eight people pulling on that knee.

There's a lot of force being applied to the ligaments,

but they're still holding strong.

Now ten rugby players. Heave!

They're pulling as hard as they can!

We can see those cruciate ligaments inside the joint

under massive stress now.

It's got to give soon, Xand. More people!

Come on!

There are now 20 people pulling on the ligaments,

and they're still not breaking.

It looks like the ligaments have beaten the rugby players!

No, Chris. This is where we bring in the real muscle.

Get on the rope.

OK.TOGETHER: One, two, three, heave!

SNAP!

Oh!

THEY LAUGH

Chris! Chris! We did it!

We broke the ligament!

Ugh! Well, not so fast, Xand.

Take a look at this!

The ligament is still intact. What?!

Xand, look, the ligaments didn't break,

the metal chain that was attaching the rope to the bones

is what's broken. Huh. We were not expecting that to happen.

That's really not what we're expecting.

So the ligaments have proved themselves stronger than 22 people

playing tug-of-war and a metal chain.

It's incredible to think how super strong your ligaments are.

Well, Xand, that tug-of-war certainly produced a lot

of sweaty, dirty laundry.

I've checked the rota, and it's your turn once again.

Now, although ligaments are very, very strong,

it is possible to injure them.

The cruciate ligaments are particularly vulnerable

in sports where you have to run very fast and change direction quickly,

sports like football.

And if you do injure a ligament, the key thing is to rest

and gently rehabilitate it.

Oh! Xand, what is it?!

I've injured my ligaments, Chris.

Have you? Which ones?

The ones I use for doing laundry.

You're going to have to do it.

Oh! I'm going to go and rehabilitate myself, Chris.

Finally, Billymena is complete.

She has 206 fully grown strong bones

with moving joints and ligaments holding her together.

I'm exhausted!

Xand, where are they? Who?

Billy and Billymena!

Um...

Have a nice break. I mean, a holiday.

So we've shown you

that your bones are made of a special honeycomb structure,

making them strong and lightweight.

Although bones can be broken,

they are incredible at fixing themselves.

Bones are held together by your super strong ligaments.

Your shoulder joint is the most flexible joint in your body.

And best of all,

we've shown you your skeleton is... TOGETHER: Ouchtastic!

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