- [Voiceover] Now to go through the appendicular skeleton
in a little more detail, see a little better view of it,
a little bigger picture.
I said pectoral girdle was the shoulder.
That's clavicle and scapulas.
Now I'm saying plural because it is right and left,
so you have two.
Pelvic girdle was the hip, so coxal bones and sacrum,
and there's two coxal bones
and then the arms: humerus, radius,
ulna, carpals, metacarpals, phalanges.
On the next couple slides,
we'll show pictures of each one of these bones
and how they orientate,
as well as the legs: femur, tibia, fibula,
tarsals, metatarsals, phalanges.
So let's start with the pectoral girdle.
You can see how the clavicle is up top
and the clavicle is going to articulate,
or meet, with the scapula.
Now, the clavicle, you see here
it's mentioned as the collar bone,
scapula is your shoulder bone,
so we have our scapula and our clavicle.
The scapula is then going to articulate with the humerus.
You can see if you follow the humerus up
how it comes to a round end.
That round end is gonna meet right at the scapula
and that's where a lot of the shoulder move.
You can bring your arm forward and back, out and in,
that's what allows all the free movement of your arm.
That's how you have that nice round service
that can move around on that
roughly flat area of the scapula.
From the humerus, you make the elbow
by having the humerus articulate,
or join, with the ulna and radius.
Now the ulna and radius are the two bones of your forearm.
The place the two bones meet up near the humerus,
right by the elbow, that portion never changes.
The radius is always on the thumb side.
You're saying, "Well hold on, how's this work
"when I can spin my forearm?"
What happens is the radius actually crosses over the ulna.
Hey, put your fingers on each side of your wrist.
You should be able to feel a bone each side.
That's gonna be your radius and your ulna,
maybe an inch up from your thumb,
but as you twist your arm, you can feel how that radius,
right above your thumb, is also twisting over the ulna,
which is going underneath.
So that's how your arm's moving
by allowing these bones to actually twist over each other.
In total, we have eight carpals
and the carpal's just your wrist.
It allows for a lot of movement here,
so you can move your wrist in all different directions.
We have five metacarpals, and these metacarpals
are pretty much the meat of your hand.
Think of the palm of your hand.
Total of five of them,
and then 14 phalanges
and really, each time you have a knuckle,
it's changing to a new phalange,
so if you're looking at your actual fingers,
not your thumb, your fingers, each one has two knuckles.
That means you start off with
one, the knuckle, two, the knuckle, three.
Three phalanges per finger,
but your thumb only has one knuckle.
That means there's only two phalanges in your thumb.
And onto the hip and legs.
You can see ow we have the coxal bones and sacrum.
So we have a coxal bone on the right and one on the left
with the very center being that sacrum.
Now remember, the sacrum is towards the back,
it's the bottom of the vertebral column.
The coxal bones are going to articulate with the femur
and you follow that femur up, which is your upper leg bone.
You can see how it turns into this
roughly round shape again,
that's fitting into a nice indent on the coxal bone.
That's your hip joint.
That's your ball and socket of your hip joint.
So it allows for all the movement you leg can do,
but as you head down the femur towards the foot,
you can see the patella, that's your knee cap, so patella.
It's meant to be there to make sure the muscles
are traveling the proper path over your knee.
Get down to the lower leg, you have your tibia,
what really bears the weight, and your fibula,
which is there for balance, stability.
Now, unlike the arm, these two bones do not cross over
a line to twist your foot.
We get down beyond the tibia and fibula,
we're down to the tarsals.
In total, there are seven tarsal bones.
These seven tarsal bones make up your heel and your ankle,
aligned for all of movement.
You have five metatarsals,
think across the top of your foot, and then 14 phalanges.
Same idea as in the hands.
Each one of the toes, toes two through five,
so not the big toe, each one has two knuckles.
That means you have a total of three phalanges per toe,
but the big toe, just like the thumb,
is only gonna have two phalanges,
so a total of 14 phalanges on the foot.