Where is your clavicle in your body
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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