Key Points on Musculoskeletal Function

Good morning, good afternoon, good evening. This is Dr. DeChaveau. Wherever, whenever you might be with me is fantastic. I hope that the class is going well for you. And of course, as always and forever, you got it, shoot me an email if you have any questions. We're moving into musculoskeletal function, which is one of my favorites because I'm a chiropractor. So really enjoy this one. This is a fun one to teach, of course. I could teach you 10 times more than we're going over, but I tried to limit it down to the basic, basic basics that you need to know. And the better you know the anatomy and physiology for this, the easier it is to diagnose things because it's fairly, I don't want to say straightforward, but if you know the structure and the function, you can denote what kind of problems can happen with the musculoskeletal system. So The musculoskeletal system is obviously going to be muscles, skeletal muscles, because don't forget there's cardiac as well as smooth muscles as well. Skeletal muscles will be voluntary muscular system that moves us through space. It'll include the joint or the bones that it's connected to and the joints that the muscles and the tendons cross. So a tendon connects muscle to bone. Tendon connects muscle to bone. A ligament connects bone to bone. So a ligament will be quite often found in highly movable areas. If you think of the foot, there's a lot of ligaments. The pelvis, there's a lot of ligaments. Not that the bony pelvis moves a lot, but the legs move a lot to move us through space. There's also other connective tissues like an aponeurosis. If you're dying to know about those other connective tissues we can talk another time but once again I'm trying to keep it to the basics and even with the basics we have 110 power points so could be a lot more if you do want to see more you can always go to my youtube channel and watch my A&P for the muscle for the muscle system and then the skeletal system and then the joint system actually have three weeks of lecture for that but anyway I'm going to review the basics which hopefully you remember and then we'll move into disorders so we're going to talk about and look at compact bone and spongy bone i'll show you a picture i'll describe it to you because the function that's much quicker and easier to understand with visuals there's multiple purposes for the musculoskeletal system i think initially we think oh okay it moves the body right and supports the body but it also helps to protect organs it stores calcium and other minerals such as phosphorus and magnesium and it's a site for a metapoisis which is the creation of red and white blood cells which we reviewed in blood so we're going to break it down into separate units we're going to do the a and p very basic physiology of the skeleton joints and muscles and the anatomy of each very basic of anatomy of each but we're going to break it down to skeleton then joints then muscles so let's get moving you should remember these bones I hope if you don't please review them and I didn't even give you all of them these are all skull and jaw bones frontal in the front parietal is the top of the skull temporal is at the temporal bone near the ear there's also occipital at the base in the back may sound familiar but it's not on those list so I won't make you responsible for it but you should know it I'm wagging my finger right here okay so the maxilla is the upper jaw and cheekbone the mandible is the one that everybody loves to move down like the skull is talking the mandible and the mandible is good to know for temporal mandibular disorder the jaw pain with clicking in the jaw which is actually not in here but that's a good thing for you to know the shoulder girdle consists of the clavicle in the front, which is your collarbone. I always remembered CNC and the scapula in the back or the shoulder blade. They both begin with S. You all know humerus, radius, and all that. I think you're all good with that. Carpals are the small wrist bones. Metacarpals are the long bones of the palm. Phalanges are your fingers. You can also call your toes phalanges. And then we have... Metatarsals, which are the long bones that lead out to the phalanges of the toes and tarsals create the ankle bones. I'm thinking these are probably familiar. your leg got it right femur kneecap patella tib fib and your shin fibula is lateral okay I'm sorry excuse me and don't forget that radius is lateral in the form but you probably know that for radial pulse now the bony pelvis begins as three bones And this is why we have multiple names for what seems to be one bone, is because it will begin as separate bones. When we talk about the fetal skeleton, it starts as cartilage. Over time, that cartilage starts to harden or ossify with calcium, phosphorus, and magnesium, but it does it in a very specific way. The bones will start to harden, so if you're looking at the pelvis, It begins as three separate ossification centers or areas that that cartilaginous matrix where the cartilage will turn into nice hard osseous bone. And with the pelvic girdle, you have an ossification center that begins about here, about here in the back, and then about here in the front. And of course, it would be on both sides. For example, this upper one, these... two areas would ossify at the same time, right? The two back areas would ossify at the same time. The two front areas would ossify at the same time. So that way you have balance between those ossification centers. So because it begins as three different locations, of course we're going to make it harder and make it three different names. And that's where you get the ileum with the iliac crest. Let me erase this. The ileum, which includes the... Back of the bone, including the iliac crest, which you should be well familiar with. The ischium, which are the hard bones that you sit on underneath here. And then pubis is easy because that's where the pubic bone is. And once again, I'm assuming you remember the parts of the pelvic girdle. If you don't, I'm waggling my finger. Go back and review. Tailbone is sacrum and coccyx. I think everybody's familiar with that. sternum you could just know sternum if you know the separate parts fantastic you probably know angle of Lewy or sacral angle to get your heart sounds and then the ribs we'll just go with ribs to keep it simple and that is the skeleton in two minutes or less very basic so bones talking about the actual structure of the bones itself on the inside It's actually a form of connective tissue. It functions as a site of fat and mineral storage, which we know as well, and a site for hematopoiesis. There's 206 bones in the skeleton, but some people actually consider what are called sesamoid bones, which I'm going to talk about in a couple of screens, as the additional bones. And we all tend to get these sesamoid bones, and they're just hardened areas in ligaments or tendons. They tend to form in areas where we have a high... amount of wear and tear. So some, um, like I think it's podiatrists that really consider there to be 208 bones in the body because there's two sesamoid bones that people tend to develop in their feet. Whatever work that I'm just totally went off road with that. I'm sorry. Let's go with 206. Okay. Skeletal division. So there's two main divisions. There's axial, just like our earth has an axis about which it rotates the axial skeleton. is going to be the skull, vertebral column, and ribcage. Appendicular will be the shoulder, pelvic girdle out, including the arms and legs, just like we're talking about appendages. So if we go back one side, axial skeleton is skull, vertebral column, really sacrum and coccyx as well you should add in there the ribs okay all these ribs that's all axial skeleton appendicular skeletons the shoulder girdle which consists of the clavicle and the scapula here and here the upper extremity the pelvic girdle which is the bony pelvis and lower extremity so that would be appendicular skeleton The cells that break down and build up bones are listed here. Osteoblasts build bone. I always remembered B and B. Osteoblasts build bone. Osteoclasts break down bone. I didn't really have a way to remember that, but it sort of in my mind sounded like clamping together. Osteoclasts, you're clamping together like jaws and you eat down that bone. And you're going to want to have a balance of both, right? You want to have osteoblasts to build that bone so we have nice strong bones. But we also use osteoclasts to release calcium. So we're able to use that calcium for heart and muscle contraction. Osteocytes are mature bone cells that help to maintain the bone matrix. Don't worry about them releasing calcium into the blood. I don't want to confuse you. Osteoclasts are the main ones that help to break down the bone matrix so we can release calcium and Phosphorus or phosphate into the bloodstream to be used by other tissues of the body. I know why they did this so Nevermind go with that if you want to know shoot me an email. I'll tell you the actual difference between them Okay, so if we look at this This is a long bone and the long bone is really the only bone that we're going to look at the separate parts of. We have long bones, we have short bones, we have irregular bones. Okay we're just going to go over the main structures of long bones because really frankly it's the most important one to do. But if you look at the long bones on the outside we have what is called compact bone and it's just that. It's bone matrix that's compacted together to make a nice strong tissue. On the inside we have spongy tissue and thank God for once it makes sense. It's called spongy because it looks like a sponge. And in this spongy tissue we can put yellow or red bone marrow. Usually in this one, which is the proximal femur, although it looks kind of weird to me. Anyway, in the proximal femur and the spongy area is where we'll make red marrow. Over time we start to put more yellow marrow into the center of the bone, but I'll show you a picture of that as well Now here's a picture of Compact bone. I'm not going to get into the microscopic aspects of it But you can see how tightly that tissue is Packed and in this tissue. I do want to remark that we have osteocytes osteoclasts osteoblasts We have our calcium matrix with calcium as phosphate and magnesium. We also have a lot of blood vessels. And if you look at these central portions, every one of these has a blood vessel. It's called the virgin canal. You may remember it from A&P. And then from that central portion to each one of these round circles will send blood out to that tissue. So bone is very vascular. People get a little confused sometimes when they think it's not. It is really vascular. And an easy way to remember that is if you break a bone, you can repair it very easily because of the blood supply to it. When we're talking about ligaments, tendons, and cartilage, they don't have a direct blood supply. They get their nutrients through diffusion through the surrounding tissues. That's why if you tear a ligament, tendon, or cartilage, you need to have it surgically repaired. But bones are very vascular. They have a direct, intricate blood supply that we can use if we're talking about a reparation or repairing process, I should say. Classification of long bones, don't let it blow your mind. We're going to go over a little bit of the structure of the long bone, which will be your femur tip. fib, humerus, radius, and ulna, but we also have flat bones. We have irregular bones. We have short bones, and they pretty much go by their names. And you can see long bones there, and then you can see short bones, flat bones, irregular bones, sesamide bones, which are the ones I explained to you that are embedded in a tendon. So just know in general those names, because other than... the long bone and the sesamoid bone which have specific parts or descriptions the other ones are exactly how they sound okay so assessment bone once again will be embedded in a tendon or really it could be a ligament as well just make note of that and then long bones are going to be the long bones that are longer than they are wide they're going to have growth plates at either end and that's an important thing to know about long bones because what that growth plate does is allows the length of those bones right it's horrible i can't draw very well So with long bones you'll have a growth plate and of course this should be rounded. Oh that's horrible I apologize. Anyway they'll have a growth plate at either end and that allows it to grow this way as well as this way to maintain the structure of the long bone and allow that long bone to grow longer. So the outer part is compact bone which I showed you and spongy bone on the inside. But I also want to point out that at the end here there's cartilage on the ends of these long bones because every one of these long bones touches another long bone or it could be a short bone or some bone of some type and the cartilage on the end allows it to be cushioned and to protect the long bone and then generally you'll also have a synovial capsule which is cartilage I'm sorry, I apologize and then synovial fluid Creating a freely movable joint which will explain in a little bit I thought I may as well go over it warm here a freely movable joint that gives us a huge range of motion Okay, so here's those other bones and that my friends brings us to a question time. So Skeletal bones are only in place to support the body and create movement true or false please answer that and then let pause it if you have to and let's move on so look i could have just looked at the picture here i apologize here's your long bob and the growth plate will be between what is called the epiphysis which is the end of a long bond e and e epiphysis epiphysis ends of long bones so your growth plate or epiphyseal growth plate, you can just say growth plate, will be between those epiphyses and the diaphysis. I'm just switching between plural and singular. You won't have to worry about it. On the outside, we have that nice compact bone. On the inside, we have spongy bone, which creates a marrow cavity, which may have red marrow in infants, most likely yellow marrow in the diaphysis in adults. Here's a nutrient vessel which shows us that it has a good strong vascular supply Now on the ends is your hyaline cartilage Just on these ends here where the joint cavity would be and you could see some hyaline here as well in the blue and those help to protect the ends of long bones and Protect them in that joint cavity and that's an important thing to note because those will be broken down When we get into arthritis or arthritis The final thing I want to talk to you about on this picture is the periosteum. The periosteum is an irregular connective tissue that's on the outside of these bones, any bones that we have. And the reason that I want to point that out is it is slightly vascular. It is vascular, but it is also innervated, which means it has a strong nerve supply. When somebody has a lot of pain from a fractured bone. It's the ends of this periosteum at the fracture, the two opposing ends get separated. And when they get separated, they can actually rub up against themselves or other structures if they're not approximated. And that's what triggers the discomfort with fractures. I also had a patient years ago who had gotten severe back pain when she was lifting a window up. Anytime you have that compressive force through the spine, you want to think fracture. And there was an old trainer trick where you take the tuning fork that has the round ends on it. I don't know the vibration, but you all know what I mean from your tuning fork from your diagnostic bag. If you take that and put it to the area where the patient says they have discomfort and pain, if they flinch, it's because the two ends of the periosteum rub up against each other in a compression fracture. And I'll be darned, that little old lady, I couldn't convince her to go get x-rays because it was fish fry Friday. She wanted her fish fry. Okay. So I said, listen, this is an old trick that I learned. And if I put this on you and you flinch, you're going to have to go to the emergency room or urgent care. And I put it on there and she flinched. Not does she just flinch. She was off the table in pain. She indeed had a vertebral fracture. She ended up going either to her doctor or urgent care or the emergency room. I don't remember. It was 15 years ago, but she indeed had a compression fracture. so tools of the trade if you think somebody has a fracture you can use that tuning fork put it right over it'll rub that periosteum against itself cool fact might help you to help somebody in the future hopefully now looking inside we've got the blood vessels which we spoke about i'm not going to well you could know that the blood vessels have travel through these reversion canals remember i told you the blood vessels run through the center of the circles and compact bone right here okay that's called a reversion canal that's where the blood supply is but and then in compact bone we have these concentric circles forming the microscopic this is all microscopic appearance of that bone of compact bone so in the inside of spongy bone we could have red marrow, which tends to be in the proximal ends. And I'll show you a picture of red marrow and its location in the whole skeletal system and a few sides. Or you could have yellow marrow. It depends on the maturity of the patient and the location in the bone. In general, if you have to guess, yellow marrow will be in the shaft, red marrow will be in the ends, but you'll see it changes as the age of the patient increases. Okay, so bone marrow could be at the ends, could be in the shaft. Generally, the shaft will be yellow, but once again, that's just a generalization. I have in the next picture, you'll be able to see. Red marrow is going to be the site of the creation of red and white blood cells. In an adult, the creation of red and white blood cells will be in the vertebra, pelvis, skull, scapula, ilium, specifically with the pelvis. So let's just look at a picture because I think this clarifies it here. So this is red marrow in an adult versus a child. And you can see with a child, they're going to have the whole skeleton. It's going to be a site of the creation of red blood cells and white blood cells when they're young. In an adult, over time, yellow marrow takes over those appendages, legs, and arms. And the proximal skeleton, the axial skeleton, the pelvic girdle, and the shoulder girdle are going to be areas of red bone marrow. I think the areas they most likely will harvest. will be ileum and scapula. For that, now when it comes to stem cells, I'm not sure where they would draw that from. So I'll look that up on our next break and let you know, because I bet you when they're harvesting either stem cells for the injections or for, you know, they're doing a lot of things with stem cells for surgeries. They're also injecting them into joints. to help the joints function a little bit better i'm not sure where they harvest that from so i'm going to look it up on the next break and i'll tell you the beginning of the next break all right so moving on to the bone matrix i think a really important thing to remember with the bone is the bone starts as cartilage so not only does it start as cartilage with the fetal skeleton and then they get ossification centers in the bones which eventually makes the bone Nice and hard calcified matrix. It also is the precursor to hard bone in our skeleton. So collagen is an important precursor to the hard skeleton. So it's important to have the nutrients to support that collagen. And vitamin C is one of the main ones, just so you know. If you don't have the proper amount of collagen as a precursor, you also won't have enough bone matrix. So calcium phosphate crystals, and there's other crystals we could talk about as well, but this is the majority of it, are deposited in that collagen, and that makes the bones hard and strong. So it's a double whammy. You've got to have good collagen. You've got to have good calcification to create that optimum bone function and structure. So bones will grow in two ways. Appositional growth is when new bone will form on the surface of a bone, which generally will make the bones thicker. As we all get bigger, we get bigger boned, and that's why we can't lose weight. Right? I'm just joking. A little bit, but really not really. As we get older, your bones just get wider. It's part of the growth process. And that's why people's feces and their body shapes change as they get older. but it's not a huge huge huge amount. Endochondral growth is when the bone eventually replaces new cartilage growth in the epiphyseal growth plate and this lengthens the bones in the young but this will stop generally between 18 to 21 for everyone and that's when we stop growing plate wise. The epiphyseal plate is your growth plate that I mentioned that's between the ends of the bones and the shaft also known as the diaphysis so proper nutrition is super important but they're also finding that physical activity especially weight-bearing activity is very important that stress on the bone actually allows the deposition of more calcium phosphate into the bone to make it stronger it's the body's natural response to weight in the bone and we know already that we need calcium vitamin d magnesium and phosphorus to put the calcium into the bones and also to get calcium out of the intestines with vitamin d growth hormone works with thyroid hormones to control normal grown bone growth and we spoke about those hormones previously we spoke about calcitonin putting it in the bone in remember right and parathyroid hormone to regulate bone breakdown So we spoke about those before in endocrine. If you have any questions, let me know. Otherwise, I'm going to move on. So don't forget that estrogen and testosterone will also help with the deposition of bone. So estrogen or it prevents a breakdown of bone, especially with estrogen. So estrogen inhibits osteoclasts. Osteoclasts break down bone. Remember, it chomps it up. so if estrogen inhibits osteoclasts it stops the breakdown of bone and then allows our bones to be stronger and healthier this is why when we undergo menopause and we have less estrogen those osteoclasts are more active which breaks down bone and it causes osteoporosis now testosterone kind of has a double whammy here first of all it maintains bones strength So in males, because they have a higher amount of testosterone, their bones tend to be stronger. Not in all cases, we're talking about generalities. But testosterone also increases bone length and density in men, making them in general bigger than females. And that's why males across the board are bigger than females. Don't forget vitamin D will absorb calcium from the intestines and reabsorption from the kidneys. The skeleton, don't forget, starts as hyaline cartilage during fetal development. Cartilage is tough and flexible connective tissue that has multiple functions in our body. So not only does hyaline cartilage form almost the entire skeleton and then we will harden it with calcium phosphate to make the nice bony skeleton, some of it is left over. Hyaline can be found in your nose. At the ends of long bones, it can also be found connecting the ribs to the sternum. As opposed to fibrocartilage, fibrocartilage, when you look at them microscopically, is an entirely different tissue. Fibrocartilage you can always think of as discs. Anywhere in the body that we have a cartilaginous disc, we have discs between the vertebra. We have discs in the temporal mandibular joint. We have discs in the elbow. and the knee, the menisci. Anywhere you see that you have a desk, you'll have fibrocartilage. Elastic cartilage is easily remembered because it's found in the ears and the epiglottis, EEE. So if you were to look at microscopically the cartilage in the ears and the epiglottis, it's going to be that elastic cartilage and it's known as such because it has more elastic fibers. My little guy who's eight years old can pull his ears way out and they snap right back. And that's a great example of elastic cartilage allowing flexibility, but that elastic fiber that is located in it microscopically allows those tissues to snap back. into shape. Now, my friends, that brings us to a little let's practice. I thought this would be fun. This might be a little hard to see. So you might want to pause it and look at them, especially the upper ones, the lower to see and the lower ones. And I have a trick question here. So don't just jump. So pause the tape if you need to. Otherwise, I'm going to answer this. This top what what bone do you think this is? Look at it very carefully because it's kind of pointing to the back. and i don't mean the ribs here it looks like the ribs i mean the one in the back that is the scapula very good i'm guessing this upper arm bone you get this that's humerus this one's a trick this bone correlates to the thumb you're like got it radial pulse rate radius this upper i shouldn't even have tested you on this that's too easy femur And last but not least, the shin bone is going to be the tibia and the fibula is the outer one. And just make note of that the fibula is actually not weight bearing. It's only the site of attachment for muscles and tendons and ligaments. That brings us to about half an hour. So I'm going to take a break. Go ahead and grab a cup of coffee and let's continue in the next video.

Good morning, good afternoon, good evening. This is Dr. DeChaveau. Wherever, whenever you might be with me is fantastic.

I hope that the class is going well for you. And of course, as always and forever, you got it, shoot me an email if you have any questions. We're moving into musculoskeletal function, which is one of my favorites because I'm a chiropractor.

So really enjoy this one. This is a fun one to teach, of course. I could teach you 10 times more than we're going over, but I tried to limit it down to the basic, basic basics that you need to know.

And the better you know the anatomy and physiology for this, the easier it is to diagnose things because it's fairly, I don't want to say straightforward, but if you know the structure and the function, you can denote what kind of problems can happen with the musculoskeletal system. So The musculoskeletal system is obviously going to be muscles, skeletal muscles, because don't forget there's cardiac as well as smooth muscles as well. Skeletal muscles will be voluntary muscular system that moves us through space.

It'll include the joint or the bones that it's connected to and the joints that the muscles and the tendons cross. So a tendon connects muscle to bone. Tendon connects muscle to bone.

A ligament connects bone to bone. So a ligament will be quite often found in highly movable areas. If you think of the foot, there's a lot of ligaments. The pelvis, there's a lot of ligaments. Not that the bony pelvis moves a lot, but the legs move a lot to move us through space.

There's also other connective tissues like an aponeurosis. If you're dying to know about those other connective tissues we can talk another time but once again I'm trying to keep it to the basics and even with the basics we have 110 power points so could be a lot more if you do want to see more you can always go to my youtube channel and watch my A&P for the muscle for the muscle system and then the skeletal system and then the joint system actually have three weeks of lecture for that but anyway I'm going to review the basics which hopefully you remember and then we'll move into disorders so we're going to talk about and look at compact bone and spongy bone i'll show you a picture i'll describe it to you because the function that's much quicker and easier to understand with visuals there's multiple purposes for the musculoskeletal system i think initially we think oh okay it moves the body right and supports the body but it also helps to protect organs it stores calcium and other minerals such as phosphorus and magnesium and it's a site for a metapoisis which is the creation of red and white blood cells which we reviewed in blood so we're going to break it down into separate units we're going to do the a and p very basic physiology of the skeleton joints and muscles and the anatomy of each very basic of anatomy of each but we're going to break it down to skeleton then joints then muscles so let's get moving you should remember these bones I hope if you don't please review them and I didn't even give you all of them these are all skull and jaw bones frontal in the front parietal is the top of the skull temporal is at the temporal bone near the ear there's also occipital at the base in the back may sound familiar but it's not on those list so I won't make you responsible for it but you should know it I'm wagging my finger right here okay so the maxilla is the upper jaw and cheekbone the mandible is the one that everybody loves to move down like the skull is talking the mandible and the mandible is good to know for temporal mandibular disorder the jaw pain with clicking in the jaw which is actually not in here but that's a good thing for you to know the shoulder girdle consists of the clavicle in the front, which is your collarbone. I always remembered CNC and the scapula in the back or the shoulder blade. They both begin with S. You all know humerus, radius, and all that.

I think you're all good with that. Carpals are the small wrist bones. Metacarpals are the long bones of the palm.

Phalanges are your fingers. You can also call your toes phalanges. And then we have... Metatarsals, which are the long bones that lead out to the phalanges of the toes and tarsals create the ankle bones. I'm thinking these are probably familiar.

your leg got it right femur kneecap patella tib fib and your shin fibula is lateral okay I'm sorry excuse me and don't forget that radius is lateral in the form but you probably know that for radial pulse now the bony pelvis begins as three bones And this is why we have multiple names for what seems to be one bone, is because it will begin as separate bones. When we talk about the fetal skeleton, it starts as cartilage. Over time, that cartilage starts to harden or ossify with calcium, phosphorus, and magnesium, but it does it in a very specific way.

The bones will start to harden, so if you're looking at the pelvis, It begins as three separate ossification centers or areas that that cartilaginous matrix where the cartilage will turn into nice hard osseous bone. And with the pelvic girdle, you have an ossification center that begins about here, about here in the back, and then about here in the front. And of course, it would be on both sides.

For example, this upper one, these... two areas would ossify at the same time, right? The two back areas would ossify at the same time.

The two front areas would ossify at the same time. So that way you have balance between those ossification centers. So because it begins as three different locations, of course we're going to make it harder and make it three different names.

And that's where you get the ileum with the iliac crest. Let me erase this. The ileum, which includes the...

Back of the bone, including the iliac crest, which you should be well familiar with. The ischium, which are the hard bones that you sit on underneath here. And then pubis is easy because that's where the pubic bone is. And once again, I'm assuming you remember the parts of the pelvic girdle. If you don't, I'm waggling my finger.

Go back and review. Tailbone is sacrum and coccyx. I think everybody's familiar with that. sternum you could just know sternum if you know the separate parts fantastic you probably know angle of Lewy or sacral angle to get your heart sounds and then the ribs we'll just go with ribs to keep it simple and that is the skeleton in two minutes or less very basic so bones talking about the actual structure of the bones itself on the inside It's actually a form of connective tissue.

It functions as a site of fat and mineral storage, which we know as well, and a site for hematopoiesis. There's 206 bones in the skeleton, but some people actually consider what are called sesamoid bones, which I'm going to talk about in a couple of screens, as the additional bones. And we all tend to get these sesamoid bones, and they're just hardened areas in ligaments or tendons. They tend to form in areas where we have a high...

amount of wear and tear. So some, um, like I think it's podiatrists that really consider there to be 208 bones in the body because there's two sesamoid bones that people tend to develop in their feet. Whatever work that I'm just totally went off road with that. I'm sorry. Let's go with 206. Okay.

Skeletal division. So there's two main divisions. There's axial, just like our earth has an axis about which it rotates the axial skeleton. is going to be the skull, vertebral column, and ribcage.

Appendicular will be the shoulder, pelvic girdle out, including the arms and legs, just like we're talking about appendages. So if we go back one side, axial skeleton is skull, vertebral column, really sacrum and coccyx as well you should add in there the ribs okay all these ribs that's all axial skeleton appendicular skeletons the shoulder girdle which consists of the clavicle and the scapula here and here the upper extremity the pelvic girdle which is the bony pelvis and lower extremity so that would be appendicular skeleton The cells that break down and build up bones are listed here. Osteoblasts build bone.

I always remembered B and B. Osteoblasts build bone. Osteoclasts break down bone.

I didn't really have a way to remember that, but it sort of in my mind sounded like clamping together. Osteoclasts, you're clamping together like jaws and you eat down that bone. And you're going to want to have a balance of both, right?

You want to have osteoblasts to build that bone so we have nice strong bones. But we also use osteoclasts to release calcium. So we're able to use that calcium for heart and muscle contraction.

Osteocytes are mature bone cells that help to maintain the bone matrix. Don't worry about them releasing calcium into the blood. I don't want to confuse you.

Osteoclasts are the main ones that help to break down the bone matrix so we can release calcium and Phosphorus or phosphate into the bloodstream to be used by other tissues of the body. I know why they did this so Nevermind go with that if you want to know shoot me an email. I'll tell you the actual difference between them Okay, so if we look at this This is a long bone and the long bone is really the only bone that we're going to look at the separate parts of.

We have long bones, we have short bones, we have irregular bones. Okay we're just going to go over the main structures of long bones because really frankly it's the most important one to do. But if you look at the long bones on the outside we have what is called compact bone and it's just that. It's bone matrix that's compacted together to make a nice strong tissue.

On the inside we have spongy tissue and thank God for once it makes sense. It's called spongy because it looks like a sponge. And in this spongy tissue we can put yellow or red bone marrow.

Usually in this one, which is the proximal femur, although it looks kind of weird to me. Anyway, in the proximal femur and the spongy area is where we'll make red marrow. Over time we start to put more yellow marrow into the center of the bone, but I'll show you a picture of that as well Now here's a picture of Compact bone.

I'm not going to get into the microscopic aspects of it But you can see how tightly that tissue is Packed and in this tissue. I do want to remark that we have osteocytes osteoclasts osteoblasts We have our calcium matrix with calcium as phosphate and magnesium. We also have a lot of blood vessels. And if you look at these central portions, every one of these has a blood vessel.

It's called the virgin canal. You may remember it from A&P. And then from that central portion to each one of these round circles will send blood out to that tissue.

So bone is very vascular. People get a little confused sometimes when they think it's not. It is really vascular. And an easy way to remember that is if you break a bone, you can repair it very easily because of the blood supply to it. When we're talking about ligaments, tendons, and cartilage, they don't have a direct blood supply.

They get their nutrients through diffusion through the surrounding tissues. That's why if you tear a ligament, tendon, or cartilage, you need to have it surgically repaired. But bones are very vascular.

They have a direct, intricate blood supply that we can use if we're talking about a reparation or repairing process, I should say. Classification of long bones, don't let it blow your mind. We're going to go over a little bit of the structure of the long bone, which will be your femur tip.

fib, humerus, radius, and ulna, but we also have flat bones. We have irregular bones. We have short bones, and they pretty much go by their names.

And you can see long bones there, and then you can see short bones, flat bones, irregular bones, sesamide bones, which are the ones I explained to you that are embedded in a tendon. So just know in general those names, because other than... the long bone and the sesamoid bone which have specific parts or descriptions the other ones are exactly how they sound okay so assessment bone once again will be embedded in a tendon or really it could be a ligament as well just make note of that and then long bones are going to be the long bones that are longer than they are wide they're going to have growth plates at either end and that's an important thing to know about long bones because what that growth plate does is allows the length of those bones right it's horrible i can't draw very well So with long bones you'll have a growth plate and of course this should be rounded.

Oh that's horrible I apologize. Anyway they'll have a growth plate at either end and that allows it to grow this way as well as this way to maintain the structure of the long bone and allow that long bone to grow longer. So the outer part is compact bone which I showed you and spongy bone on the inside. But I also want to point out that at the end here there's cartilage on the ends of these long bones because every one of these long bones touches another long bone or it could be a short bone or some bone of some type and the cartilage on the end allows it to be cushioned and to protect the long bone and then generally you'll also have a synovial capsule which is cartilage I'm sorry, I apologize and then synovial fluid Creating a freely movable joint which will explain in a little bit I thought I may as well go over it warm here a freely movable joint that gives us a huge range of motion Okay, so here's those other bones and that my friends brings us to a question time.

So Skeletal bones are only in place to support the body and create movement true or false please answer that and then let pause it if you have to and let's move on so look i could have just looked at the picture here i apologize here's your long bob and the growth plate will be between what is called the epiphysis which is the end of a long bond e and e epiphysis epiphysis ends of long bones so your growth plate or epiphyseal growth plate, you can just say growth plate, will be between those epiphyses and the diaphysis. I'm just switching between plural and singular. You won't have to worry about it. On the outside, we have that nice compact bone. On the inside, we have spongy bone, which creates a marrow cavity, which may have red marrow in infants, most likely yellow marrow in the diaphysis in adults.

Here's a nutrient vessel which shows us that it has a good strong vascular supply Now on the ends is your hyaline cartilage Just on these ends here where the joint cavity would be and you could see some hyaline here as well in the blue and those help to protect the ends of long bones and Protect them in that joint cavity and that's an important thing to note because those will be broken down When we get into arthritis or arthritis The final thing I want to talk to you about on this picture is the periosteum. The periosteum is an irregular connective tissue that's on the outside of these bones, any bones that we have. And the reason that I want to point that out is it is slightly vascular. It is vascular, but it is also innervated, which means it has a strong nerve supply.

When somebody has a lot of pain from a fractured bone. It's the ends of this periosteum at the fracture, the two opposing ends get separated. And when they get separated, they can actually rub up against themselves or other structures if they're not approximated.

And that's what triggers the discomfort with fractures. I also had a patient years ago who had gotten severe back pain when she was lifting a window up. Anytime you have that compressive force through the spine, you want to think fracture. And there was an old trainer trick where you take the tuning fork that has the round ends on it.

I don't know the vibration, but you all know what I mean from your tuning fork from your diagnostic bag. If you take that and put it to the area where the patient says they have discomfort and pain, if they flinch, it's because the two ends of the periosteum rub up against each other in a compression fracture. And I'll be darned, that little old lady, I couldn't convince her to go get x-rays because it was fish fry Friday.

She wanted her fish fry. Okay. So I said, listen, this is an old trick that I learned. And if I put this on you and you flinch, you're going to have to go to the emergency room or urgent care.

And I put it on there and she flinched. Not does she just flinch. She was off the table in pain.

She indeed had a vertebral fracture. She ended up going either to her doctor or urgent care or the emergency room. I don't remember.

It was 15 years ago, but she indeed had a compression fracture. so tools of the trade if you think somebody has a fracture you can use that tuning fork put it right over it'll rub that periosteum against itself cool fact might help you to help somebody in the future hopefully now looking inside we've got the blood vessels which we spoke about i'm not going to well you could know that the blood vessels have travel through these reversion canals remember i told you the blood vessels run through the center of the circles and compact bone right here okay that's called a reversion canal that's where the blood supply is but and then in compact bone we have these concentric circles forming the microscopic this is all microscopic appearance of that bone of compact bone so in the inside of spongy bone we could have red marrow, which tends to be in the proximal ends. And I'll show you a picture of red marrow and its location in the whole skeletal system and a few sides.

Or you could have yellow marrow. It depends on the maturity of the patient and the location in the bone. In general, if you have to guess, yellow marrow will be in the shaft, red marrow will be in the ends, but you'll see it changes as the age of the patient increases.

Okay, so bone marrow could be at the ends, could be in the shaft. Generally, the shaft will be yellow, but once again, that's just a generalization. I have in the next picture, you'll be able to see.

Red marrow is going to be the site of the creation of red and white blood cells. In an adult, the creation of red and white blood cells will be in the vertebra, pelvis, skull, scapula, ilium, specifically with the pelvis. So let's just look at a picture because I think this clarifies it here.

So this is red marrow in an adult versus a child. And you can see with a child, they're going to have the whole skeleton. It's going to be a site of the creation of red blood cells and white blood cells when they're young.

In an adult, over time, yellow marrow takes over those appendages, legs, and arms. And the proximal skeleton, the axial skeleton, the pelvic girdle, and the shoulder girdle are going to be areas of red bone marrow. I think the areas they most likely will harvest. will be ileum and scapula.

For that, now when it comes to stem cells, I'm not sure where they would draw that from. So I'll look that up on our next break and let you know, because I bet you when they're harvesting either stem cells for the injections or for, you know, they're doing a lot of things with stem cells for surgeries. They're also injecting them into joints. to help the joints function a little bit better i'm not sure where they harvest that from so i'm going to look it up on the next break and i'll tell you the beginning of the next break all right so moving on to the bone matrix i think a really important thing to remember with the bone is the bone starts as cartilage so not only does it start as cartilage with the fetal skeleton and then they get ossification centers in the bones which eventually makes the bone Nice and hard calcified matrix. It also is the precursor to hard bone in our skeleton.

So collagen is an important precursor to the hard skeleton. So it's important to have the nutrients to support that collagen. And vitamin C is one of the main ones, just so you know. If you don't have the proper amount of collagen as a precursor, you also won't have enough bone matrix.

So calcium phosphate crystals, and there's other crystals we could talk about as well, but this is the majority of it, are deposited in that collagen, and that makes the bones hard and strong. So it's a double whammy. You've got to have good collagen.

You've got to have good calcification to create that optimum bone function and structure. So bones will grow in two ways. Appositional growth is when new bone will form on the surface of a bone, which generally will make the bones thicker.

As we all get bigger, we get bigger boned, and that's why we can't lose weight. Right? I'm just joking. A little bit, but really not really. As we get older, your bones just get wider.

It's part of the growth process. And that's why people's feces and their body shapes change as they get older. but it's not a huge huge huge amount. Endochondral growth is when the bone eventually replaces new cartilage growth in the epiphyseal growth plate and this lengthens the bones in the young but this will stop generally between 18 to 21 for everyone and that's when we stop growing plate wise.

The epiphyseal plate is your growth plate that I mentioned that's between the ends of the bones and the shaft also known as the diaphysis so proper nutrition is super important but they're also finding that physical activity especially weight-bearing activity is very important that stress on the bone actually allows the deposition of more calcium phosphate into the bone to make it stronger it's the body's natural response to weight in the bone and we know already that we need calcium vitamin d magnesium and phosphorus to put the calcium into the bones and also to get calcium out of the intestines with vitamin d growth hormone works with thyroid hormones to control normal grown bone growth and we spoke about those hormones previously we spoke about calcitonin putting it in the bone in remember right and parathyroid hormone to regulate bone breakdown So we spoke about those before in endocrine. If you have any questions, let me know. Otherwise, I'm going to move on.

So don't forget that estrogen and testosterone will also help with the deposition of bone. So estrogen or it prevents a breakdown of bone, especially with estrogen. So estrogen inhibits osteoclasts. Osteoclasts break down bone. Remember, it chomps it up.

so if estrogen inhibits osteoclasts it stops the breakdown of bone and then allows our bones to be stronger and healthier this is why when we undergo menopause and we have less estrogen those osteoclasts are more active which breaks down bone and it causes osteoporosis now testosterone kind of has a double whammy here first of all it maintains bones strength So in males, because they have a higher amount of testosterone, their bones tend to be stronger. Not in all cases, we're talking about generalities. But testosterone also increases bone length and density in men, making them in general bigger than females. And that's why males across the board are bigger than females. Don't forget vitamin D will absorb calcium from the intestines and reabsorption from the kidneys.

The skeleton, don't forget, starts as hyaline cartilage during fetal development. Cartilage is tough and flexible connective tissue that has multiple functions in our body. So not only does hyaline cartilage form almost the entire skeleton and then we will harden it with calcium phosphate to make the nice bony skeleton, some of it is left over. Hyaline can be found in your nose. At the ends of long bones, it can also be found connecting the ribs to the sternum.

As opposed to fibrocartilage, fibrocartilage, when you look at them microscopically, is an entirely different tissue. Fibrocartilage you can always think of as discs. Anywhere in the body that we have a cartilaginous disc, we have discs between the vertebra. We have discs in the temporal mandibular joint. We have discs in the elbow.

and the knee, the menisci. Anywhere you see that you have a desk, you'll have fibrocartilage. Elastic cartilage is easily remembered because it's found in the ears and the epiglottis, EEE. So if you were to look at microscopically the cartilage in the ears and the epiglottis, it's going to be that elastic cartilage and it's known as such because it has more elastic fibers. My little guy who's eight years old can pull his ears way out and they snap right back.

And that's a great example of elastic cartilage allowing flexibility, but that elastic fiber that is located in it microscopically allows those tissues to snap back. into shape. Now, my friends, that brings us to a little let's practice. I thought this would be fun. This might be a little hard to see.

So you might want to pause it and look at them, especially the upper ones, the lower to see and the lower ones. And I have a trick question here. So don't just jump.

So pause the tape if you need to. Otherwise, I'm going to answer this. This top what what bone do you think this is?

Look at it very carefully because it's kind of pointing to the back. and i don't mean the ribs here it looks like the ribs i mean the one in the back that is the scapula very good i'm guessing this upper arm bone you get this that's humerus this one's a trick this bone correlates to the thumb you're like got it radial pulse rate radius this upper i shouldn't even have tested you on this that's too easy femur And last but not least, the shin bone is going to be the tibia and the fibula is the outer one. And just make note of that the fibula is actually not weight bearing. It's only the site of attachment for muscles and tendons and ligaments.

That brings us to about half an hour. So I'm going to take a break. Go ahead and grab a cup of coffee and let's continue in the next video.

Transcript for:Key Points on Musculoskeletal Function

Transcript for:
Key Points on Musculoskeletal Function