- [Voiceover] The human skeleton self has
usually about 206 bones.
Now I say usually because some people have more,
some people have less.
206 is just the typical average.
Now the human skeleton is broken up
into two main parts.
We have first off the Axial skeleton.
This includes your Skull, the Vertebrae, and your Sternum.
So it's pretty much the central axis of your body.
It's the main core.
The other part is the Appendicular skeleton.
Now the Appendicular skeleton's made up of
the Pectoral girdle; the Pectoral girdle is your shoulder,
The Pelvic girdle; which is your hips,
and your limbs; arms and legs.
So pretty much everything coming off
your torso is part of the Appendicular skeleton.
Shoulder, arms, hips, and legs.
Let's look at the skeleton model here.
We can see we have the cranium up top.
The cranium is made of several different bones of the skull.
Be the Maxilla, can see it's the upper bone of your jaw.
Mandible's the lower bone.
The Mandible better be the only bone
that moves in your entire head.
Cause if any other bone is moving
something's either broken or fractured;
something's really wrong.
The Mandible should be the only one that moves.
Sternum, right down the center.
You can see that's right what's
commonly known as the breast bone.
But the Sternum is the proper name.
The Ribs, now the Ribs go all the way
from Rib one down through the bottom one,
you can see kinda hanging off the bottom is Rib 12.
So we have a total of 12 pairs of Ribs.
The Vertebrae.
Now in this case the Vertebrae are towards the bottom label,
but those Vertebrae run all the way up to your head.
So you can see the entire long Vertebral column.
And then as we get down to the bottom of the Vertebrae,
we come to the Sacrum.
The Sacrum is still part of the Vertebrae.
What it is is actually a couple of Vertebrae
that have fused together; should make
a really solid structure there.
So the Sacrum, the bottom of the Vertebral column.
If we start looking at the Appendicular,
remember we're thinking shoulder, arm, hip, leg.
So we have the Clavicle and Scapula.
The Clavicle, a lot of times you can think of that
as the collar bone.
So, Clavicle's the term.
Scapula, a lot of times known as the shoulder blade.
But Scapula is the proper term.
Humerus, Ulna, Radius.
You can see the Humerus is the bone of the upper arm.
Ulna and Radius are the two bones of the lower arm.
The Radius is always the one that's one the thumb side.
And then your wrist is Carpals.
Maybe you've heard of Carpal tunnel syndrome.
Well it got it's name because
Carpal tunnel syndrome has the Carpals being affected.
Then you got to the Metacarpals
and finally the Phalanges.
Actual fingers themselves are the Phalanges.
The actual bone of your hip is called the Coxal bone.
A lot of the time that's referred to as the hip bone,
but Coxal bone is more accurate.
We have the Femur, the upper leg;
very strong, very large bone.
Patella, more commonly known as the knee cap,
but Patella's what we're going with.
Then Tiba and Fibula.
Now an interesting side note here,
the Tibia is taking all the weight.
The Fibula bears no weight.
The Fibula is just meant for balance.
You can actually completely have your Fibula crushed
and still be able to walk afterwards.
Had a student several semesters back
(mumbles) and both Fibula completely crushed,
couldn't rebuild them, so they actually took them out.
Wouldn't even know the individual had a problem,
unless it was mentioned.
So the Tibia is really what bears the weight,
the Fibula is balancing issues.
Then we get down to the ankle, you have your Tarsals.
Tarsals are all those bones that
allow the ankle to move around.
Metatarsals, think of the arch of the foot.
Heading down to the actual toes, the Phalanges.
And yes, the Phalanges are both toes and fingers;
same exact term.
Alright let's look a little closer at the skull.
Here we have a lateral view up top,
so we're looking from the side.
The one at the bottom is an inferior view,
it's has if you're looking from
the actual chest up towards the head.
You have a Frontal, makes sense it's the front of the skull.
A Parietal bone covers most of
the back half back top portion.
We have the Temporal bone, think about
where your temples are, side of your head.
And the External Auditory Meatus, that's your ear.
That's how the sound goes into your ear.
Occipital bone, back of your head.
Now if you look at the bottom picture
you can see how it's the back,
but also wraps underneath.
You can see that nice big opening called
the Foramen Magnum.
Now that's where you brain and spinal cord meet.
So, Foramen Magnum, where the brain and spinal cord meet.
Your Sphenoid bone is the thing in yellow.
It kinda helps to keep everything together,
so right in the center.
We have our Ethmoid bone, you can see it
inside the eye socket a little bit.
We have our Lacrimal bone, that's where
your tear ducts are.
We have our Nasal bone, it's the
boney portion at the top of our nose.
We have our Zygomatic bone, you think cheek bone.
Zygomatic bone, that's your cheek bone.
Maxilla is the upper jaw.
Mandible is the lower jaw.
Then we have this Palatine bone.
So look at the bottom figure, look where
the roof of the mouth is.
See all the purple is the Maxilla,
but that little bit of blue there,
that's the Palatine bone; helps make up
the hard surface at the top of your mouth.
The Maxilla and Palatine bone.
And right in the middle of the nasal cavity comes the Vomer.
It's that brown one dead center
you can see from underneath the skull; the Vomer.
If we move on to the Vertebrae you can notice we have
the Vertebrae all numbered, one through seven,
one through 12, one through five.
Well these Vertebrae are grouped into regions.
We have seven Cervical Vertebrae, that's your neck.
A total of 12 Thoracic Vertebrae, that's where
your rib cage comes off of.
We have five Lumbar Vertebrae, that's your lower back.
So you have seven, 12, five.
You can kind of think of it as breakfast, lunch, and dinner.
Breakfast at seven, lunch at noon, dinner at five.
It might not be totally accurate for everyone,
but hey if it helps you remember go for it.
And that Sacrum again.
Sacrum is five fused Vertebrae,
so it's like one big one,
but it's really five of them that have fused together.
Then the end is the Coccyx, it's three or four
Vertebrae that are usually fused together.
So the Coccyx.
Now that's just the average, sometimes people
can end up with two or three,
sometimes it goes five or six or seven or even more.
When an infant is born with a large amount of vertebrae
from the Coccyx, they actually have a small tail
protruding from their bodies.
That's just because there are too many Vertebrae
and they just actually poke out of the body.
So more often than not that's surgically removed right away,
to prevent any complications.
Alright so as we mentioned, Vertebral column has
Cervical, Thoracic, Lumbar, Sacral, Coccygeal.
But all those bones aren't actually
touching the bones directly,
right where they meet for weight.
They have what are called Intervertebral disks in between.
It's cushioning of cartilage.
The cartilage is in between the main parts of the Vertebrae,
the main round bodies; helps give them cushioning,
but also allows for flexibility.
It allows them to pivot forward and back
allowing you to bend with your back.
Ribs, we mentioned 12 pairs already.
Now the bottom two though, pairs number 11 and 12,
they're kinda unique because they're called floating.
They're floating because they do not attach to the front.
They have no attachment up the Sternum.
So they're kinda just floating down in the bottom,
in between all the muscle.
Sternum, right in the middle of your chest.
It's where most of the ribs come and articulate,
or come together.
The Sternum really is actually three bones fused together.
So it's three separate bones
that all grown and fused together
to create a solid front surface.
So again looking at the Vertebrae,
you can see the main bodies point out here;
the top figure.
And then you have the blue Intervertebral disk.
Those blue disks are what allow
for the Vertebrae to kinda pivot back and forth
back and forth.
The bottom picture, it's showing you a herniated disk.
Now the herniated disk a lot of times
it just means the cartilage is being pushed out.
Well the problem is what does the cartilage push into?
The cartilage is pushing into that yellow thing,
which is a spinal nerve.
If you pinch a spinal nerve a
whole lot of things can happen.
Look at the view of the Rib cage and Ribs here
with the Sternum right up front.
You can see the Vertebral column is in the back,
starting at C7 or Cervical seven
and going down to L2, Lumbar two.
Sternum is right in the front.
You can see the three different regions of Sternum,
You can see all the Ribs.
If you notice when the Ribs are counted down,
numbers 11 and 12 don't have any blue.
That's because remember 11 and 12 are going to be floating.
They don't attach to the front.
All that blue is the cartilage that
helps to hold the Ribs to the Sternum.
So remember those floating Ribs at the bottom
can't forget about those floating Ribs.