We've been learning the axial skeleton. And now we've reached this most central axis of the axial skeleton, the spine, all right, the spine are also called the vertebra. Or if you're feeling fancy, the vertebral column, it's gonna be made of 24 vertebrae plus the sacrum and the coccyx. And we have an image showing this here. We see the axial skeleton from the side. We see the skull, the vertebral column color coded so that we can label it plus the ribs. And we also see here uh the coxal bones added in so that we can see the pelvis. Now, when you're learning the vertebrae, each vertebra doesn't have its own, you know, completely unique name, we put them into groups and label them that way. So the first group that we're gonna learn is gonna be the cervical vertebrae. Now, if you remember, cervical refers to your neck. So these are the vertebrae that are in your neck and there are seven of them. Now, when you learn the vertebrae, one way to name them is to take the first letter of the group that they're in. So here it's C for cervical and then number them from the top of that region. So Cervical, we start, it would be the C one, C two, C three all the way down to the C seven. And I'll label that on our uh on our image here. This is gonna be C one through seven. All right, the first two cervical vertebrae are unlike any other vertebrae. And so we're gonna go over those. Now, the first one is called the Atlas. So the Atlas also just called C one, the Atlas, we're gonna say holds up your head like Atlas holding up the heavens. So your heads sits on the vertebral column and it sits directly on that C one on the Atlas. And if you know any mythology, Atlas, I actually forget if it's Greek or Roman, but Atlas had to hold up the heavens on his back for eternity. So your Atlas is holding up your head and when you nod your head, just like this, just a little bit, what you're actually doing is the head is rocking back and forth on the Atlas. Now your C two or your axis. Well, it's easy to remember these two together because they're both a words. So I always remember them together. The Atlas and the axis. Well, the axis allows the head to turn on an axis. So when you do this, what's actually happening is that Atlas is turning back and forth on the axis. OK? With that, let's talk about our other regions as we go down, we reach the thoracic vertebrae, there's gonna be 12 thoracic vertebrae. Remember your sort of chest region is your thoracic region? And what makes the thoracic vertebrae unique is that they all articulate with ribs. Each thoracic vertebra articulates with two ribs, one on each side and we can number these T one through 12. So we're gonna see it right here in orange. We have the T one through 12 going down, we reach the lumbar vertebrae. If you remember lumbar, that refers to your lower back, there's gonna be five lumbar vertebrae and these are gonna be the biggest thickest, heavy vertebrae because they're bearing so much more weight, the vertebrae as you go down, get bigger because they carry more and more weight. So we're gonna name them one through five. And we see right here. L one through five. Oops, I wrote a three. There we go and one through five. OK. Finally, we've reached the sacrum and the sacrum is gonna be the back part of the pelvis. So together the sacrum and the coxal bones or hip bones make up the pelvis. Now, the sacrum is sort of part of this vertebral column. It's a single bone, but it's grown from five fused vertebrae. And so you can still see and identify the different bones that fuse together to make it. So you can un label those bones s one through five if you need to. So we can see the sacrum here. I'm just gonna circle it. Here is the sacrum that back part of the pelvis. The final part of the vertebral column is going to be the coccyx and the coccyx. That's your tailbone. This comes from 3 to 5, typically four fused vertebrae. So these f small vertebrae fused together, usually they fused into one bone, sometimes it's more than one bone, but usually it's one and you can see it just right down here, your coccyx. Now, the dame coccyx comes from Ancient Greek and in ancient Greek coccyx refers to the cuckoo bird because the ancient Greek ananimous thought that it looked like the beak of a cuckoo bird. Ok. Now, as we look at our spine, you'll see your spine is not straight like a flagpole. It has curvatures and specifically, we're gonna name four curvatures of the spine. You see him right here. We have 12, 34. It sort of makes this wavy line as it goes up. And those four curves are just named after the regions of the spine, named after the vertebrae that are in that region. So we have the cervical curve, thoracic, the lumbar and the sacral curve. And instead of just being straight like a flagpole, having that bend that just gives your spine just a little bit of spring to it, right. So it acts a little bit like a spring, makes it not such a rigid pole. Now, the other thing that you'll notice about this, these vertebrae is that they're not right on top of each other in between each one, you have this little cushion of connective tissue and cartilage and these are the intervertebral discs. So this is cartilage and uh connective tissue that cushions between the vertebrae, right? So you don't want just bone on bone banging down on each other. And you also want to have a little bit of flexibility in your spine. Your spine isn't super flexible, but it can move. And when it's moving, that's those vertebral discs just squishing down and stretching just a little bit between the different vertebrae. Now, importantly, those vertebral discs will just note they are absent between C one and C two. And you remember that's your Atlas and your axis. And that's because instead of being sort of fused with these vertebral discs where it just has a little bend between them goes, you can actually twist back and forth. All right. That's our Te Brook column. I'll see you in the next video.
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example
The Spine Example 1
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5m
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Our example wants us to match the section of the spine to the type of vertebra found there. Then it wants to fill in the number of vertebrae found in that section and determine if the curve of the spine is concave or convex posteriorly in that region. All right. So as we look at our image here, we see a spine, we see the curves of the spine and I can tell that this is a side view of the spine and it wants us to know anterior and posterior here. So this is the anterior side and this is the posterior side. So this, this was in a person, this person would be facing forward in that way. What I can tell that is all these uh processes sticking out the back. Those are those bumps that you can feel in your spine as you touch your back. All right. So here we have our different regions, they're listed in alphabetical order, not in the correct order. So let's go through them and match them up. All right. Cervical. So which region is your cervical vertebrae? Well, remember it's cervical that refers to your neck region. So the cervical region is gonna be up at the top here and that is going to be a how many bones in your cervical region? Well, we said it was c one through 77 cervical vertebrae. And now this curvature question concave or convex posteriorly, right? Before I answer that, I just want to remind myself of concave and convex because it always gets me confused. So always remember this trick that I learned in elementary school, I draw a curve and I say, all right, which side looks like you're walking into a cave? Well, that's the con cave side, which means that the other side is the convex side. So as I draw the curve on this cervical vertebrae, it's sort of curving that way. So that to me looks like that concave side is facing posterior. OK. So that brings us to the coccyx. So which letter here is the coccyx? Oh Remember the coccyx, that's your tailbone. So it down here on e I actually think not all the bones are there, but we're not gonna worry about that. Uh So the coccyx is gonna be e how many bones make up your coccyx? Well, your coccyx is a single bone, but I'm gonna put in parentheses in here. 3 to 5 or you could just write four. Remember, the coccyx is made of these smaller bones that fuse together an adult to make that one bone of the tailbone. All right. Finally, the curvature here before you did say the curvature though, I just wanna stress remind you we had four major curves of the spine. The coccyx is not one of those major curves, it does curve so we can still answer the question. So I'm gonna draw that curve that I see here in. And as I look at that, well, which is uh which side is facing posteriorly. Well, that looks like the convex side. But again, the coccyx, not one of the major curves of the spine that you need to remember. But we can still see the curve. All right. Next up, we have lumbar. So which one is your lumbar vertebrae? Well, remember lumbar, that's your lower back. So those are those big heavy vertebrae of the lower back. So as I look here, lumbar is going to be c how many lumbar vertebrae do you have? Well, see, we said lumbar, it was l one through 55 lumbar vertebrae and I'll draw in the curve. All right. That's the curve I see for those vertebrae. So which way is that facing? Well, the posterior, posterior side looks like it is concave, which brings us to the sacred, all right, the sacrum, which letter on here is the sacrum. Remember the sacrum is that bone? It's part of the vertebral column, but it connects it to the pelvis. So I can see here that's gonna be D so d the sacrum, how many bones make up your sacrum Well, definitely only one bone in the sacrum. But again, I'm gonna put in parentheses five here because remember the sacrum is made of five fused sacral vertebrae. Definitely only one bone in an adult. All right, curvature. Well, I'm gonna draw in the curve again. All right. So is the convex or concave side facing posteriorly? Well, to me, that looks like the convex side is all right. Lastly, we have the thoracic vertebrae and we have only one letter left. But hopefully you could be figure out anyways. All right. So lastly, we have b here, remember thoracic that refers to sort of the chest region, the area of your rib cage. So thoracic vertebrae is going to be uh b how many do you have? Well, just like pairs of ribs, you have 12 thoracic vertebrae and we can draw in the curve as I draw on that curve. It looks like the con vex side is facing posteriorly. Now, just a quick reminder on the curves as you go down, these curves should alternate. So it should say uh it should be uh concave, convex, concave, convex. And then remember the coccyx isn't an official curve and that gives your spine that little bit of spring action that it has. OK. So with that, we've named the vertebrae, we've figured out where they are. We've said how many there are and we've identified the curves good work or problems at all.
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Problem
Problem
In a skiing accident, Marcio broke his T2 and T3. Where is his injury?
A
In his neck.
B
In the middle of his back.
C
In his upper back.
D
In his lower back.
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Problem
Problem
Which part of the spine will have fewer individual bones as you age?