your

The Clavicle (or collarbone)

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that was foolish she totally that's too

heavy as you've seen from the title of

the video no doubt this week we're going

to be looking at their clavicle we've

looked at the scapular in detail before

we've looked at many of the muscles of

the shoulder we looked at the shoulder

region in general and the humerus and

glenohumeral joint and blah blah blah

blah so let's not leave out the clavicle

because it is an important part of the

shoulder girdle we'll talk about the

bone the bony bits ligaments muscles

attached to it stuff like that and the

joints I'll talk a little bit about my

own clavicle my collarbone that I

fractured to give you a bit of insight

into what that can be like so okay so

what does the clavicle do I mean the

thing you can see here is there's the

thing about the clavicle is look is this

lovely this lovely s-shaped bone then

you can palpate it pretty much along its

entire length in most people I say mines

got I've got a novel on it there if you

can see that though there's a love there

which is we're paying them right now

there's a love there which is where I

frakked identify this is normal and this

side there's a big lump where the bone

went like that there's a good reason why

it went like that once I got my x-rays

let's have a cup of my x-ray someplace I

look at that

now the clavicle runs from the manubrium

of the sternum which is the eights your

skeleton so we've got the vertebral

column the ribs the sternum that's the

aches your skeleton that's the central

bit right that's where your HCO pit is

so there's the clavicle runs from the

manubrium of the sternum out to the

scapula and then from the scapula we

have the glenohumeral joint so the upper

limb is hanging from the scapula now

post evenly we see that the scapula is

not attached to any bone it has a lot of

muscles

it's covered in muscles which are

supporting the scapular and holding it

in place what this does for us is it

means the shoulder girdle is highly

mobile so we can put our arms and our

hands into a wide range of positions but

it means that it's a little bit weaker

and all of these bones need to be

supported by muscles so there's a

trade-off going on on here but it means

that the clavicle is the only point at

which the upper limb is connected bone

early to the eggs your skeleton so it

acts as a strut

so cyclists often it's like the

fractured clavicle is a fairly common

fracture it's a common fracture in

cyclists it's most commonly caused by a

direct blow to the shoulder so with me I

was here I was cycling along I've just

done some tempo reps Knossos bit chilly

so I got me Gilly a me back pocket you

know sleeveless vest right wind proofing

and started putting it on while I was

cycling along didn't see the pothole so

yeah and the arms were up here hit the

bottle wheel banks into the kerb and I

went over and landed on my shoulder like

that yeah I know and landing on my

shoulder caused pressure this way and

we'll see how well anchored this is so

it caused the bone to fracture like this

the key thing here is and you'll see

this on the TV if you're watching

cycling on the TV and there's a crash

and you see a cyclist on the floor and

they try to push themselves up so you

sat on the ground because you just

crashed and you try and lift your ass

off the floor and you can't and that's

what happened to me so you sit down and

you try and push yourself up and it

doesn't it just doesn't work there's no

pain yet because it's just happened but

it stopped and instantly you know ah

I've broken me clavicle and that gives

you a clue as to what it does so it's a

strut while most of this is hanging most

of the shoulder girdle is hanging from

the aches your skeleton by muscles it's

this strut that's very important in

in pushing it away from the eggs your

skeleton and allowing those muscles to

work and give you leverage to move the

scapula and the upper limb right

does that help so we think of a crane

you know you got the struts and the

support in the crane that's it's a bit

like that so it's a strut it's a

mechanical strut that's what it does and

when it breaks that mechanical strut

doesn't work and you can no longer push

up now I was doing dips in the gym this

morning because I do a lot of work on me

shoulders just to keep them strong and

safe for the various sports I do if you

watch the vlogs and that dip motion the

the strut of the clavicle is crucial in

allowing you to do that into dips your

body weight and push yourself back up

again so that's another example of the

clavicle acting as a strut doing its job

so that's what it's for now the other

thing about it is I've got a clavicle on

its own but that's it doesn't matter is

it's got this lovely S shape isn't that

nice really really nice s shape and it

goes there moves quite a bit so if you

palpate your scapula right you feel your

scapula and you move your shoulder

around it moves a lot right so it's got

a joint to either end it's got a whole

bunch of ligaments we'll we'll look at

the bony bits we'll look at the joints

either end we'll look at the ligaments

we'll talk about it we'll run through

the muscles on this guy here and then

we'll talk about a couple of the

injuries you can get so the clavicle is

considered to have a double curve occurs

eight and then curve so it occurs

anterior and posterior lis it's a long

bone but it doesn't actually have any

bone marrow unlike a typical long bones

was a little bit special in the way that

it develops it has a sternal end and an

acromial end so this is the scapula here

the coracoid process and the acromion is

up here and articulates with the with

the acromion which means we have a

sternal facet and in a chromium facet

we'll see that in fact the sternal end

articulates with the first costal

cartilage to the cartilage of the first

as well as the manubrium so this is the

shaft here it's got a couple of lumpy

bits we talked about well there's

there's a groove for subclavius under

here lynnie Anatomy is really hard isn't

it there's there's a huge amount or

there's a huge amount of detail and the

question is always how much do you need

to know why don't okay I don't know who

you are and in some videos I'm a little

bit lighter in some videos I'm going a

little bit deeper trying to tailor to

different tastes and needs but you know

I'll highlight the stuff that's

important and kind of skip through the

stuff that's less important so things

like you know the subclavian at the the

groove for subclavius yeah the co noids

tubercle yeah and that sort of thing

yeah it's not crucial so we'll do the

the joints first and we'll add the

ligaments on top all right so in this

end here the medial end of the clavicle

we've got the sternoclavicular joint so

the sternal facet of the clavicle

articulates with the manubrium of the

sternum and the rib of the first and the

cartilage of the first rib it's a it's a

synovial joint

it has a fibrocartilaginous disc in

there and you may see it described as a

plane joint or as a saddle joint so a

plane joint is like you know like a flat

surface lighting thing and your saddle

joint is there's got a bit of a saddle

shape to it and if you think about the

movements you can do this on your room

you can do this on yourself right the as

you move your if you move your scapula

really so if you pull your scapular

anterior probably a shoulder anteriorly

you can feel that this guide doesn't

move you can feel that the the clavicle

is moving this away in this way so you

can move your clavicle anteriorly and

posteriorly all right as you move your

glenohumeral joint anteriorly and

posterior

so it kind of angles that way and then

as you elevate and depress the shoulder

as well you can feel

or the clavicle at that sternoclavicular

joint moving so it's kind of moving in

in two directions we talked about little

bit of rotation there as well so it's a

proper synovial joint there's a fair bit

of movement there of course don't forget

when you breathe you've also got that

pump handle movement of the sternum

which is occurring here but it's an

incredibly strong joint it's very rarely

dislocated because of the ligaments

tying it all together the other end of

the clavicle the lateral end as I said

it articulates with the acromion so we

have an accrual facet at the end of the

clavicle there this is another synovial

joint and again it is described most

most commonly as it as a plane joint so

there's a little bit of sliding motion

allowed now these two bones are anchored

together really well as we'll see for a

couple of reasons

and again there is I think yeah yeah I

think studies generally show that in

many people maybe most people there's

also a fiber cartilaginous disc in the

acromioclavicular joint as well and

again if you think about how this moves

it's kind of a little bit of movement

there at this end as the scapula moves

around the case or however we're talking

about struts right so for the clavicles

one strut as if you had a second stroke

if you had a second anchoring strut back

here like if the clavicle was anchored

the a steel skeleton you wouldn't be

able to to move your shoulders

anteriorly and posteriorly would you

then only hinge upwards and downwards

because you'd have the two struts to see

what I mean so you wouldn't be able to

move your arms as freely this is the

principle of you having one strut in the

shoulder girdle right okay ligaments

what can we welcome I was going to look

for the sternoclavicular ligaments

there's no stone

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a little representation on here

manubrium clavicle ligaments up here

we've got ligaments running between the

sternum and the clavicle so these are

sternoclavicular ligaments really really

tall tough covering the synovial joint

capsule we've got an anterior

sternoclavicular ligament and we've got

a posterior sternoclavicular ligaments

that too now there's another ligament

should i get some tape running between

the the first rib and the car is of the

first rib and the clavicle

that's a costo clavicular ligament right

because of course costal refers to ribs

isn't it and then this might be a bit of

a long ligament this we have a ligament

that actually runs from one clavicle

over the the sternum the disturbin arch

there so the other clavicle and that

would be the inter clavicular ligament

so all of those ligaments and they're

tough ligaments are reinforcing the

sternoclavicular joint so you can see

why that joint is really really strong

and very rarely dislocated and of course

if you think about okay there's or

supported by muscles but your upper limb

is a big thing so that's anchoring all

of that to the aches your skeleton

anchor as well the muscles are bigger

and stronger but you get the idea okay

other end then other end so on this one

we can see the ligaments so remember on

the clavicle we've got two lumpy bits

here we've got the coracoid process

named after the beak of the bird

coracoid like a beak poking through

there and we've got the acromion we are

particularly interested in the

acromioclavicular joint the AC joint and

there is an acromioclavicular ligament

surrounding that joint capsule and

supporting that acromioclavicular joint

making it also a very very strong joint

and you might think oh I wasn't prettier

that's enough that's doing a good job

but no there is well there are two

ligaments from the coracoid process to

the clavicle so together they get called

the core a co-curricular ligament which

is very sensible right so that's running

from the coracoid process of the

clavicle and maybe you can see the

benefit of this in that the upper limb

here is hanging from the scapula this is

where the glenohumeral joint is so by

tying the coracoid process to the

clavicle you're then hanging this weight

of the upper limb from the clavicle as

well and when we look at the muscles

we'll see how the clavicle is also

hanging from the exoskeleton fight by a

whole bunch of muscles there's a whole

bunch of clever suspension stuff going

on there in which helps in terms of if

you think by gravity and standing

upright and pipe it anyway okay so those

are the core co-curricular ligaments and

there are two of them the colloid

ligaments and the trapezoid ligament now

the the co noid ligament is medial and

it's kind of if we spin it around you

can see that it's kind of fan shaped so

when you look at it in textbooks you

know you look at it from like one

perspective it just looks like a line

but if you think about it in three

dimensions

is running from the clavicle and that's

the colloid tubercle that I was talking

about this under there that's what

that's for is for that ligament to

attach to and then that runs down of

fans out so the coracoid process of the

scapula the trapezoid ligament then is

lateral and it's this ligament here so

those two ligaments together get called

the the cora co-curricular ligament and

the other thing they do is they force

the the clavicle and the scapula to be

tied together into word together as you

as you move the shoulder girdle right

staff ligaments so knowing about the

joints is important

there's none of names of them really but

then an understanding of the ligaments

of the clavicle that's the most

important bit about the clavicle really

and also a relationship relational

anatomy of stuff around it

muscle wise we can work this out as we

go I think there are six muscles here

sternocleidomastoid boom

sternocleidomastoid so it's a it has two

heads going to the stronger it's the

sternum one going to the collied Oh

clavicle so kleiner refers to the

clavicle and then of course it's coming

from the mastoid process up pierce

sternocleidomastoid

that's attaching to the medial most part

of the clavicle we can see this muscle

here as well this is a cisterna hyoid so

the hyoid bones up here you know it's

the highway bone there it's running from

the hyoid down to the against sternum

and the clavicles who gets to know how

it gets called stir in a highway bit

it's actually attached to the clavicle

down here as much as anything else

pectoralis major so look on the inferior

surface of the clavicle pectoralis major

is attaching to you know a big bulk

certainly we've described the medial

third of the clavicle on this model

looks like a fair bit more than that

if you continue around in fear really

then we've got this deltoid muscle you

know the rounding of your shoulder

that's on the inferior side of your

clavicle here and that's continuous with

the scapula then with the acromion and

the spine of the scapula and then we can

see this here so here's trapezius and

this is what we talk about we talk about

suspensory things suspending the upper

limb from the exoskeleton you can see

how trapezius the upper fibers of

trapezius are running from the ACO

skeleton and they're spreading out to

the spine of the scapula so to the

superior edge of the spine of the

scapula and to the superior edge of the

clavicle so then that's holding the

clavicle and the scapula up and then the

deltoid is hanging on there everything's

hanging off those bones the deltoids

supporting holding the humerus into the

joint and stuff like that is that six

one two three four five I've missed

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I miss the most obvious one subclavius

there's a mass of code subclavius that

runs from the first rib and probably the

first costal cartilage as well it's

inferior to the clavicle and he's not

forgot is because it's not on the model

I was working out as I went wasn't way

but foreplay vyas is as the name

suggests inferior to the clavicle and

it's kind of a slender muscle running

along like this it helps depress the

clavicle and probably where the

clavicular fracture maybe even helps

protect prevent the the ends of the bone

from going into bad places and kind of

holds it all together repulsion so then

the subclavius muscle is also helping

anchor the clavicle to the ACO skeleton

isn't it in a similar way to the

ligaments okay so what can go wrong two

main things most common thing is a

fracture of the clavicle as I said

earlier so this most commonly is either

most is it a little commonly fractured

bones gonna be up there isn't it

so it's often caused by a blow to a

direct blow to the shoulder falling on

the shoulder causing that strut to take

too much force and snap it snaps like a

ruler which means it might break into or

it might break into three pieces with

two fractures and in my break

close in my break in the middle of my

very closer to one end or t'other

it can also break from a fall onto an

outstretched hand because these long

bones are very good at transmitting

force up their length and as I described

these these ligaments are so strong that

that fourth thing gets transmitted

across here and

weakest bear gives way which is that

that the bone of the clavicle so the

joints are often described as being

stronger than the clavicle itself and

that's why the clavicle tends to

fracture rather than damaging the joints

if if a joint does get injured it's

going to be this one the

acromioclavicular joint and this is a

separated shoulder and acromioclavicular

dislocation or an AC separation or an

acromioclavicular separation that's what

all those terms are referring to the

referring to the same thing it's not a

shoulder dislocation a shoulder

dislocation describes the humerus

usually dislocating inferiorly but a

separated shoulder is this

acromioclavicular joint being separating

there because it's um because it's the

sort of your joint there is a cartilage

covering the articular surfaces and as I

said there's often often usually I don't

know how common it is but there's a

fibrocartilaginous disc inside there so

if you look at this joint on an x-ray

there should be a gap between the

acromion and the clavicle and that would

be normal but so that's you need to like

recognize recognize the normal situation

and if it's like a mild separation and

that gap might have got wider if it's a

significant separation so you can have a

great one grade to grade 3 ac

separations depending upon the damage to

the soft tissues then of course the

clavicle might be apparent in you're in

the wrong not in the right place you

might see a little bit of you know it's

in the wrong place there so when I broke

my clavicle it was I think probably the

most painful thing I've ever done

because it fractured and then what

happens is sternocleidomastoid you see

how if you've broken it here then

sternocleidomastoid which is quite a big

muscle he's going to quite happily

elevate the medial third of the clavicle

so the clavicle tends to go up like like

this I don't think trapezius has too

much of an effect on it because it's

quite well anchored at this end

that could be wrong but I mean that's

got to be a good thing right because

then is pulling the fractured ends of

bone away from all the important things

in here the blood vessels break your

plexus and that sort of thing but in my

case it meant that the two ends of the

bone bone is filled with nerve endings

we're rubbing against each other so as

long as I kept it completely still so

okay pain but okay but as soon as it

moved just a little bit oh it's you know

green horrible horrific pain so I have

some nice pink it's just get me cycling

Jersey off so bear that in mind that it

can be incredibly painful and if the

bone has moved much then the advantage

is you can let it form a callus on its

own and it'll stitch together the repair

quite nicely all you need to do is have

a sling and take the weight off the off

the shoulder take the weight off the

clavicle so it can't support any weight

anymore so you take the burden of the of

the upper limb off it and wait for it to

set get there after a week after two

weeks it's pretty good you know they'd

have the same sort of pain problems as

the calluses started to knit together

and that sort of thing now I've had a

buddy who crashed his bike we were

racing in was it in Austria yeah we were

doing triathlon Austria he had a wet day

on his race and he crashed I think the

bottom of a descent or something and he

did the same broke his clavicle but the

two ends were not touching so he

displaced the two ends of his clavicle

they fractured apart from one another

quite happily and he had very little

pain he still have painkillers be was

much better off than I was because you

didn't have the two bits of bone rubbing

against each other

dang sorry Boris he had to have surgery

to put the two ends back together and

nail them together on a plate well yeah

screwed together on a plate that's what

the pro cyclists do you know they break

it surgery straight away plate it

together and they can start training

pretty soon again they don't lose too

much fitness craze in them now the AC

joint separation

it's potentially worse been repairing

bones is pretty easy

repairing ligaments is very very slow

ligaments have a poor blood supply their

biology is not really very well

understood it's not very well I mean the

biology of tendons is very well

understood and ligaments is even is even

worse but they take a very very long

time to heal if it's if it's a really

good tear it might never heal and again

you might use surgery to repair that or

you might just have a conservative

approach and not bother just sling the

arm until everything starts to repair a

little bit another one of the anatomist

here Andy did easily came off his

motorbike bombing along came off his

mobile by flying along the floor no

problem

Tilly what do you hit a lamppost or

something and then of course you hit it

that way and then he pull the acromion

away from the clavicle so instead of

having a blow this way which tends to

fracture the the scapula sorry which

tends to fracture the clavicle he had a

blow this way which then pulls the

scapula away from the clavicle and you

tear that joint even though it's a

really really tough joint and these

these Cora Co curricular ligaments here

as well and a really really serious

separation these can be torn as well and

then you've got a bigger problem because

it's you know the joints loose so you

know supporting the weight of the upper

limb off the clavicle only more so those

are the two big ones

so the important stuff today is the the

ligaments either end that's the most

important bit muscles should be adding

on to knowledge you have of this region

anyway bony lumpy bits there are many

and really the joints relate to the

ligaments and it's just the names of the

joints need to remember all right

there we go that was a bit of a trip

down memory then relay on it see you

next week

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