Transcription
Hello, you are most welcome ladies and gentlemen to Real in Partition Moments on Tuesday night Anatomy with Daniel. Open today's section. We continue with a part two of the anatomy insights that we've already begun. So I hope you watched it already, but if you've not done so, kindly get the video link, yes, and watch it. So at the end of the day, all that we'll be doing today will make complete sense.
Now, today I begin with, of course, the types of bones that we have in the human body. Okay, so we begin with the types of bones. Now, one thing that you should be aware of is that we have what we call short bones. Short bones, yes. Now, anytime we talk about short bones, one thing I want you to be aware of is that short bones, with their length and their weight, okay, by way of, I mean, I'm talking about their length and their weight, it is almost the same. Now, most of the times, the shape that they present with, you say they are cuboidal. Okay, it says it happens almost the same length, yes, as well as the width or the breadth, if you, I mean, quality as such. So that is what we have to look at.
Now, if you look at this area, okay, the wrists, your wrist, okay, in anatomy, wrist is carpus. So any bone in the carpal region, in the carpus, okay, will be related to the wrist. Therefore, use the word, you know, carpal. So typical examples of short bones, we have what we call the carpal bones. Now, the last time we got to know that for each hand, or for each upper leg, we have what we call eight carpal bones, and they are organized into what we call the proximal row and, of course, the distal row. There were four. We gave a mnemonic, okay, from proximal to distal. I mean, at nomenclating them from lateral to medial, there was a mnemonic like "Some lovers take wishes that they can't handle." Okay, we reset all resistance. So what are some of these bones? These are the carpal bones. Carpal bones are generally described as short bones, okay, with their basket for it, okay, lunate, form. We're talking about trapezium, trapezoid, hamate. Having that, often generally we say they are short bones. But my friends, there's a catch for this guy, which is sitting over here, okay. This guy that you see, it's rounded away. You can feel it from your own. Okay, if you look at your wrist region, okay, where the little finger, the pinky, okay, are the base over here, you can feel a certain rounded, I mean, over there. That bone is called pisiform. Now, although we are saying that all these carpal bones are short bones, the exception is with that pisiform. I'll come to that. The pisiform is actually a sesamoid. It's a sesamoid. The reason is simple because it develops within the tendon of a muscle. I'll tell you that that tendon is called the tendon of what we call flexor carpi ulnaris. Literally, try to understand all these things why we give these names. Okay, so there's a real specimen that I'm having dissected hand that we have over here. So we can see the wrist region, the short bones over here at the level of the wrist, okay, they are the carpal bones. I'm telling you that the exception, the one you can feel over here, okay, that is towards the little finger, the pinky, okay, that's the left finger, the moon, at the base over here, okay, this guy sitting on top of the triquetrum, is what we call the pisiform. And that pisiform is not really a short bone. Generally, ask you that, I mean, what are the short bones? You say carpal bones. But the exception is with this guy, the pisiform. It is a sesamoid. Why? Because it develops within the tendon of a muscle. That tendon is the tendon of flexor carpi ulnaris muscle. Okay, that's the point. We will come to this again.
If you look at the feet, the foot too, the same way we have bones of the wrist, the carpal bones, the same way bones of the ankle, the tarsals. Now, the tarsal bones, last time we got to know that they were seven for each foot. We're having seven, you know, tarsal bones. And these tarsal bones, yes, generally we describe them as being short bones. Okay, now, why are we saying that? Because by the same principle, almost the same length as, you know, the weight, it will describe the magnesium. But my friends, there's a catch. So whenever you talk about these, I mean, carpal bones, yes, you can talk about talus, we can talk about, I mean, towards the medial aspect, okay, towards the lateral aspect, we're talking about cuboid, cuboid bone. And then from, of course, I mean, medial to lateral, the most, I mean, proximal aspect of the bone, we are having what we call the medial cuneiform, the intermediate cuneiform, and, of course, the lateral cuneiform, or first, second, and third, you know, cuneiforms. These are short bones. But my friends, there's a catch. This guy over here, which is under the rear aspect of our foot, okay, would you call it a heel bone? The layperson will call it, yes, anatomically, we call it calcaneus. Okay, so that's calcaneal bone. Yes, it's a typical bone. Yes, we prefer to put it under irregular bone. Okay, so these are some exceptions that I want you to be aware of because having this kind of atypical bone shape, which you cannot, I mean, which cannot fit in any of these descriptions that I'm going to give you, yes, because of its atypical shape, we will rather put it under, you know, irregular bone. Okay, so that is one thing that I want you to be aware of.
So the first bone type that they are what you call short bones. So we are looking at the types of bones, and those types of bones, we are looking at is based on the shape. The first one we'll do that is a short bone. Short bone. And I told you that in the short bone, the key thing over here is that the breadth and then the length, yes, it's almost the same. Namely, exact cuboidal. Examples: carpal bones, bones of the wrist, and of course, tarsal bones, bones of the ankle. Now, if you have seen short bones, then it makes sense that there will be another bone type which will be long. Okay, yes. So if I have short bone, then there will be another one which will be long bone. So the long bones that we have, then the point is that unlike the short bone where the breadth and the weight is almost the same, in the case of long bones, what we see is that this time around, the length is far, far greater than of course the width or the breadth. Okay, that becomes a long bone. Okay, that is important. Now, I'll spend for us to really understand the bone, I'll spend most of my energy on this long bone. Okay, so after going through all the bone types that we'll look at, perhaps you'll really understand this bone tissue. We'll be looking at, I'll spend most of my energy on this long bone.
Now, for that reason, if you are having a long bone, as you can see in my hand, there's a long bone, there's such a bone of the arm, humerus, that's a long bone. Why? Because long bones represent with two ends. You have two ends. And what are these two ends? This is one end, and then there's the other end. So there's the proximal end of the bone, and I'm having the distal end of the bone. Now, later, as we move on, I'll explain to you that the proximal end of the bone, whenever we say end of the bone, that is what we call the epiphysis of the bone. Everything I'm going to explain all these things for you. So I'm going to have a proximal epiphysis, and I also have a distal epiphysis. Okay, so that's what we are going to see. Whereas, head to a reference point. That's the humerus, because this one is very closer. This end is very crucial to the reference point value of the shoulder joint, it becomes the proximal end of the proximal epiphysis. And then this question is further away from those joints, this shorter end, and therefore we call it the distal epiphysis. That is what we see.
Now, if we've seen that it's going to have two ends, then there's going to be an intermediate region. That intermediate region, you are aware at the senior high school, we were told that as the shaft of the bone, or what I call the body of the bone. Okay, so there's a shaft of the bone. Now, the shaft of the bone, later we get to know that we call it diaphysis. Diaphysis. Okay, so the bone, if you qualify to be a long bone, then you are going to have two ends. Now, for that reason, most of the long bones we have in the human body are vertically placed. Okay, yes. So they will be vertically placed in the body like this, vertically placed. Now, with the exception of one of them. With the exception of one of them. Now, I'll come into the exception. So what are these long bones that we've been talking about? So examples will be, of course, the humerus, then of course, you go to what we call the ulna and of course the radius. The radius and all that, they are also part of it. They will report to their lips. By way of the lower legs, this guy, the same way, there's the tibia, the weight-bearing bone of the leg, the tibia. Okay, so the same way, proximal and distal shaft, that's all end. They're the same way for, of course, the fibula, the slender bone that we have over here, okay, which will also have a proximal end, you have a distal end, and it will have an intermediate region. Thus, okay, these are examples of the long bones that you have in the human body.
Then I told you that these long bones that we have, yes, they are vertically oriented, except one of them. And which is this one that I'm talking about? Now, this one I'm talking about is this guy. Now, this guy, in which the layperson will call it the clavicle. Sorry, the layperson will call it the beautiful bone. Now, because at the end of the day, you know, those who go for this kind of, I mean, beauty competition, these models, okay, they tend to be a bit athletic. They are not too shabby, they're a bit athletic, and therefore we tend to see this kind of, I mean, over there. Now, some people, okay, some Ghanaians, they're afraid to call it, you know, Rawlings' chin. Okay, there was one time where there was firemen in Ghana, and of course, their ruling president as of that time was His Excellency, you know, Jerry John Rawlings. And therefore, people would call this one Rawlings' chin. Okay, but don't write this anyway. If we are asked to tell us the layman's term for clavicle, then your answer is clavicle. Only and only. Well, I may accept beauty bone, but not Rawlings' chin. Okay, so that was that. Clavicle. For this shape, there's also a long bone. Now, this time around, it is the only horizontally placed long bone. If you have, if you guys rather horizontally placed, now because it's horizontally placed, then it means that yes, again, we are going to have the intermediate shaft or the intermediate body or the intermediate diaphysis. But what we are not going to see is that we are not going to see proximal end and distal end.
Now, look at this. This one is from a side, getting to the middle of the body. And therefore, it tells me that if that is true, that we are going to have rather a medial end, and then the one that is further away from the main line of the body, it becomes what we call the lateral end of the bone. Okay, so that is what we are going to see with the clavicle. Lateral end. And we're going to have a rounded medial end of the bone, not proximal and distal ends. Okay, that is what I want you to be aware of. Now, this bone, this bone is also very special. Now, the key thing is that I'll take you through all these, I mean, bones bit by bit. You will see that we will get to know that now, sometimes you take this kind of chicken, this meat, it can be the thigh on the chicken, and then you may be enjoying the bone. You break through it and all that. You get through that, there will be a cavity without bone. That cavity will get to know that is called the medullary cavity, which is still without bone marrow, what you enjoy, okay, eating. Now, the key thing is that in the case of this clavicle, always alone, when I cut through it, I won't find any medullary cavity. It does not have a medullary cavity. Now, one thing, the last time when we reviewed the French hospitals, that on the skeletal system, and for that matter, the bone, we've got to know that inside the bone, we have a medullary cavity, which of course, is a storage site for fats. Now, for the medullary cavity, that's okay. It does not have a medullary cavity. Therefore, when I come through, I won't see anything. It means that it will not be relevant as far as human purposes is concerned, production of blood cells is concerned. Okay, so that is also another useful term that I want you to be aware of. That is a clavicle. That is that this bone, okay, it is the frequently fractured bone that we have in the human body. The frequently fractured one, okay, that is what we see. I'll be explaining all these steps, I mean, all these things for you, okay, later. The frequently fractured bone in one body.
Now, one thing that we find is that it is the first bone to begin ossification. Now, once I've mentioned this, then let me be quick and tell you something that they have two ways, even bones develop. There are two ways in which bones develop. Now, bones can develop from scratch. Now, one thing that we get to understand, I'll be teaching some sort of connective tissues, connective tissue, the basic tissues. Well, I've done some videos. They can wear more that one connective tissues, you get to know that whenever we say connective tissues, now when you were in your mother's room, okay, around the third week of intrauterine life, whenever I say intrauterine life, inside your mother's womb, inside your mother's future, okay, during that time, around the third week, what will happen is that you are an embryo, and we're having three layers, okay, the embryo proper was having three layers, namely ectoderm, mesoderm, and endoderm. Ectoderm, mesoderm, and endoderm. Now, mesoderm will be very important in giving rise to what you call connective tissues. Now, remember that the bone is also an example of connective tissue. The collagen, yes, it's an example of connective tissue. In other words, all these guys or both of these guys will be derived from what they call connective tissue, from what we call mesoderm. Okay, so that was one thing that we have to understand. Now, at this point in time, I'll tell you that this mesoderm, another way that we can use over here, we make some kind. So I can see that they will be derived from what we call connective tissue mesenchyme. Okay, that is one thing that you have to be aware of.
Now, there are two ways in which bones develop. Generally, if I'm a long bone, you develop via what we call endochondral ossification. Generally, you will develop something called endochondral ossification. Okay, that is the way in which generation develops. That is called endochondral ossification. It's the same as bone formation. Another word that is synonymous with ossification is osteogenesis. Osteogenesis, okay, making these kind of bones. So one of the ways in which bones develop is we are going toward the whole endochondral ossification. Now, whatever the word "chondral" has to do with cartilage. "Endo" means within. Now, "chondral" means cartilage. So first, we don't form the bone from scratch. That's what we are talking about for long bones. I'll first have to use that connective tissue mesenchyme to perform cartilage model. That cartilage model, precisely, I'll let you know that it is hyaline cartilage. We will get to know that I have three kinds of cartilages. We have hyaline cartilage, we have elastic cartilage, we have fibrocartilage. We'll come to these, but the first thing I want you to be aware of is that these bones, especially for long bones, they don't develop from scratch, that's straight from from connective tissue mesenchyme. They become bone. They have to first form what we call hyaline cartilage. And thus, hyaline cartilage will serve as a model from which the bone will come in what form? From it. Okay, so the bone replaces this cartilage eventually, gradually. So that was one thing we'll be doing all these things. Okay, so that is what we call endochondral ossification.
Now, the next number you have to also be aware, when shall come to especially for flat bones, they will develop from scratch. So straightforward from connective tissue mesenchyme, we will get what we call the bone. That one will fall as intramembranous ossification. Okay, so for now, there are two ways in which bones form: endochondral, generally for long bones; intramembranous, generally for flat bones. Now, the reason why I talked about this is that if I look at the clavicle, it is the first bone to begin its ossification around the sixth week of intrauterine life. As when it begins its ossification, but my friends, interestingly, it is the last one to finish ossification. Yes, sometimes they say that the first can be last. Yes, this is a typical case. That yes, I mean, the first one to begin its ossification, but the last one to finish its ossification. Now, generally for all these bones, the time that all these bones will ossify, including this clavicle, which I'm saying is the last one to finish its ossification, will be around age 25. Okay, so by 25, we expect that all these bones have become, you know, ossified. Okay, that is one thing about this clavicle. Now, there are other interesting facts about this clavicle, which as we move on, we'll talk about it. Okay, so that's the only horizontally placed long bone that we have in, of course, the human body. Although it is a long bone, interestingly, the medial portion, which is a bit, okay, through all the bone and endochondral ossification, endochondral, just as a small portion of the medial portion. So this portion will develop via what we call endochondral ossification. Majority of the shafts, including the lateral end, okay, will go through what you call, I mean, intramembranous ossification.
Now, I told the lateral end is flat, why? Because it is articulating with this guy, who is also part of it, we call it, I mean, a, I mean, it's completely. I'll come to that one. This is articulating with it. And because of that, I always say that bad company corrupts good manners. Now, ordinarily, because it's a long bone, I expect that it should go through only endochondral ossification. But because of its proximity, its association with that, I mean, the scapula, its acromion, okay, a problem where is a flat bone, yes, this portion is assuming characteristics of the flat bone. With the medial portion, where is articulating with what we call, I mean, the manubrium of the sternum, we'll come to that, okay, showing what we call endochondral ossification. Okay, so that is one thing that you have to be aware of. Now, for this reason, if I've mentioned that you have two kinds of ossification, and your ossification, or you can also say osteogenesis, because we are using hyaline cartilage model, replacing them, replacing it to become more osteogenesis, and they also have, I mean, I mean, intramembranous ossification. There is something that I want you to also be aware of.
Now, when you take the long bone, whichever long bone we are talking about, now, one thing you should be aware. Good. Now, what we have, cameras, let me use it. The primary center of ossification, yes, will be in what we call the diaphysis, the shaft of the bone. That is where the primary center of ossification will be. And then primary center of ossification will appear before birth. Now, I told you that for instance, the clavicle, you know, appearing, the humerus around the seventh week of intrauterine life, intoxication, primary ossification. So primary ossification center, that is where the diaphysis, the shafts, okay, will develop. And that one will take place when you were in your mother's womb. So they appear before birth. They appear in intrauterine life period. Now, on the other hand, the opposite aspects, where I'm talking about the epiphysis, the ends of the bone, that one, they will develop, you know, after birth. After birth, that is when they develop at different, you know, stages. Now, for this reason, why are these things important? Second ossification centers appearing at the details after birth, okay, at different ages, that's one useful term that you have to be aware of. The reason is that sometimes you may take an X-ray of a person, maybe there's a fracture. So it should be aware, you should be able to distinguish between, let's say, an X-ray showing fracture of a bone and also an X-ray showing that there hasn't been the appearance of what we call the secondary ossification center. Because, for instance, if I take the X-ray of the arm of someone who is, let's say, less than, let's say, a three-month-old individual, now I'll see the diaphysis because that one will develop when you're in your management, the primary center. But their epiphyses, most of them, okay, will not be present, will not be visible, right, because they will take time to develop gradually. Okay, so that's one thing I want you to be aware of. Okay, so that is that.
So when you look at these long bones, you've seen them. Okay, now, there was one time I was teaching, and some students asked me this question that, yes, these are also long bones. Okay, all these guys, they are long bones like this. The metatarsals. These are metatarsals. Metatarsals. These are phalanges of the feet. The same way, these are metacarpals. These are phalanges of the hand. Yes, we can see that they also show the same, you know, organization. They also have this body, whereas the diaphysis. Yes, you can see that it's also having two ends. But my friends, there's a catch. There's a catch. There's a big catch over there. That these ones, they are not true long bones. Rather, we prefer to call them miniature long bones. So another thing that I want you to be aware of regarding these long bones we are talking about is the presence of miniature long bones. Miniature long bones. They are long bones, all right, morphologically, but there is something about them, who, it doesn't make them true long bones. So we prefer to call them miniature long bones. Now, why miniature? The reason, example, one thing that we realize is that now, I told you that for long bones, yes, there's going to be an intermediate shaft, that's a body, the diaphysis. That is going to have two ends. Which I told you that in the epiphysis, I have the primary ossification center in the epiphysis, okay, both proximal and distal epiphysis, I'll have secondary centers of ossification in both of them. This is not the case for what we call the meta. And the metatarsals, as well as, of course, the phalanges. It's not the case for them.
Now, why is this? The reason is simple because one thing that we find with these bones, okay, is that if I should just take one of them and demonstrate that to you, what we see is this. This is how the bones appear. Now, you see that the base can be one of the ends, the head can be one of the ends, yes, that's true. But obviously, I'll explain something to you in no time. The types of epiphyses that we have, we will see that for this, I mean, metacarpals, metatarsals, okay, if I want to name them, and for metacarpals, the one which is in line with the thumb, is the metacarpal one. Carpal two, carpal three, carpal four, carpal five. Now, one thing that we realize, okay, is that this head, this shaft will have the primary, you know, ossification center. But for metacarpal one, sorry, for metacarpal two, all the way to five, and metatarsal two, all the way to five, what we see is that yes, primary center of ossification will be here, but the secondary center, okay, of ossification will be with the head. With the head, that is what we see for metacarpals one all the way to, sorry, metacarpal two all the way to five, and metatarsal two all the way to five, they will show this ossification. It means that for you to be really an epiphysis, you should have a secondary center of ossification in both of the ends. But we will see that it is only one of the ends of the bones, so to speak. We should be having our the second center of ossification in this case, the head. That is what one thing that we we have to be aware of. Okay, so if I have such a phenomenon, that is for meta, I mean, for meta two all the way to five, they will have this presentation. It means that they have only a single functional epiphysis. Now, the so-called epiphysis, if you may call it, it does not function. Why? Because it doesn't have secondary center of ossification. So that's the principle.
Now, the next thing is that in the case of the metacarpal one and metatarsal one, for the feet, as well as the phalanges, all these guys, all the phalanges, rather, they are secondary. Substantive central ossification is with the base. That is, it means that for them, they don't have the secondary ossification. Therefore, also for them to say that they are functional epiphyses inside the base and not in the head. That is why for these metacarpals, metatarsals, and phalanges, we call them miniature long bones. They are not complete long bones, so to speak. Okay, so that's also an important thing to look at.
Now, so we've seen these long bones. If you've seen these long bones, there's another bone type that you have to be aware of, and that is what you call flat bones. Flatness. Okay, now, what about we talking about flat bones? One useful thing that I want you to be aware of in this pattern, that is flat bone. Now, anytime we hear the word squamous, it means flat. So some of these bones, they are very flat areas. So sometimes we call them squamous part of that same flat bone. We will come to these bones, we understand them. Now, flat bones generally, generally, we'll talk about flat bones, they tend to be curved. They are curved. They tend to be curved. They are curved. And importantly, they are very protective. They will protect internal organs against mechanical injury. Now, what do I mean by this? Now, if I look at typical examples that we have, we have bones of the scalp. Bones of the scalp. Now, whenever I take this bone of the scalp, then it reminds me of something. Now, if you take a very close look, you will see, especially over here, you see that I have this portion of the bone, that's what I call the internal plate or the inner plate of the bone. Then I have the intermediate region, which you can see sounds pointy one. You can see some areas where there are some reflections in there. Then I have the outer plate. Now, what we see is that for most, for all these, I mean, what we find, okay, is that they present with an outer plate, with an outer plate, outer plate, or something called compact bone. Now, I'll be explaining this one to you. An outer plate of compact bone. That's compact bone. You get to know the other name that I'll call it will be cortical bone. Cortical, like the cortex. Cortical bone. And then you also have an inner plate. This time around, also of compact bone. So this inner plate is also compact bone, just like the outer plates. Then I also have another outer plate, also of compact bone. Now, you saw something that there was a region which was somewhere in between the outer plate of one part bone and the inner plate of compound bone. This area made of rather spongy bone, spongy bone. And this pointy bone, yes, normally we call diploe. So you may see the word diploe. So intermediate diploe, intermediate region, what you call it, diploe, or some kind of French word, diploë. Somewhere between this kind of two diploe, that is what we see.
Typical examples of these flat bones, like bones of what we call the cranium. Now, most of these cranial bones, these cranial bones, yes, they are flat bones. Yes, so for instance, last time we talked about it, you can see it's a bit flat. This kind of flat bone protecting the brain. You say they are protected. They are going to protect internal organs against mechanical energy. So I have this, this is a frontal bone. You can see it has kept. I can see what you call the parietal bone on either side. I can see the occipital bone. We can talk about this guy over here, okay, over here, we talked about the temporal bone. It's also flat. Okay, all these guys. Now, my friends, one key thing I want you to be aware of is that sometimes we see the bones of the skull, they are flat bones, but it's not all of them. Like if I take this sphenoid, sphenoid, sphenoid bone, it appears flat. There are some butterfly regions, but it's hard knocking of irrelevant arrangement. I prefer to put it on the area of global. If I take something like the ethmoid bone, okay, which will project, will have some projections in the nasal cavity, it's also having this kind of irregular, you know, appearance. Okay, these are the things. Now, for most of the facial bones, they are irregular. Most of them, they are irregular. Like if I take the zygomatic bone, have an atypical shape. If I take this mandible, this maxilla, okay, all these, these are most of them are irregular bones. So generally, for most of the classic flat bones, which we said that they will develop mainly via what we call intramembranous ossification, they could only be bones that form what time you call the vault of the skull. Vault of the skull. And the vault of the skull is the one I showed you, this guy, this calvaria. The vault of the skull. And whenever we say most of the skull, we get to know that another name for it will be called calvaria. The layperson will call it cap or better, soap. The real way that it may be seen, however, will become burial. Calvaria. Now, calvaria is of similar form. So the plural, instead of writing singular, and we make it calvaria. Okay, that is how we normally include this. We inflect it with the platform, then you have to take the um, I will make it calvaria. So we have several of these ones, then we have calvaria. Okay, so that is also an important thing that you should be aware of.
Now, not only that, if you come here, you will see this bone. Good boy. It's your channel. That breastbone. The breastbone. The layperson called the breastbone. That's sternum. It is also a flat bone. Now, again, if I look at these guys, these ribs. These ribs are also flat bones. These ribs, okay, these are flat bones. Now, one thing that you find with these ribs is that sometimes we get a bit confused. Now, remember, they are curved, they are fun, okay, they are protective, protecting many the lungs, the heart, as well. Okay, they have flatness. Even the scapula is also a flat bone, protective. Okay, now, the ribs, which I call them costal bones, costal bones. Okay, one problem we find is that some people think it's a long bone. Yes, it's very wrong. It's elongated, but it's a flat bone. Okay, that's one thing that makes people think it is a long bone is that we tend to have this in having what we call a head, but it's not rounded. Now, mostly for long bones, they tend to be rounded. That's one thing. They tend to be rounded, cylindrical, as you can see over here, rounded. That is what we see. So it is not a long bone. So these are classic examples of the flat bones.
Now, whenever I mention flat bones, okay, and I talk about bones of the calvaria, then it reminds me of something. It reminds me of something that there are some bones, they confine, they are in the skull region, right? Yes, no problem. But what happens is that now, you were told that in senior high school, that bones of the skull, they are joined by some fibrous, immovable joints, which you call them sutures. S-U-T-U-R-E-S, which is now. One thing that we find is that even between these kind of fibrous joints, sometimes, especially at the rear aspect, you know, of the skull, we tend to see other bones developing within the sutures. And sometimes we also call them wormian-like, a web, means. So another bone type, which whenever I talk about these kind of flat bones, which you have to also make mention, okay, is what we call the sutural bones. They are flat anyway, but the only thing like that, it tends to, okay, they develop in between the sutures, okay, within sutures, we call them sutural bones or wormian bones. Sutural or wormian. Yes, so that's okay. Now, sometimes, if we take a very close look, okay, at what I have here, sometimes, let me show you something. Okay, now, there's a small bone. I'm trying to use this marker to show you the outline. Now, there was a suture where the yellow thing is, I can see a small bone developing in there. Okay, it's not supposed to be there. Okay, so we call it sutural bone. Similarly, there's another bone over here at the right, especially on the right aspect of that, I mean, of the skull, okay, we have it. There's also a suture developing within a suture. So you're traveling or wormian bones, they are also flat bones, but we call them wormian or sutural bones. They form within sutures of bones.
Now, for this reason, it reminds me of something. Now, sometimes we see that in the adult human being, we have 206 bones. Normal case scenario. But my friends, there's a big catch. There's a big catch. Because these bones, they work beyond most adults. They have more than 206 bones. I tell you the reason is that now, for instance, assuming I don't have this kind of wormian bones or sutural bones, you get someone with a lot, maybe two or three or even more of these six bones at the right aspect of the skull. Therefore, such a person, the total number of bones will go beyond 206 bones. Okay, so that was also one useful term that you should be aware of. One way in which bones, the total bones will go beyond 206 bones. Okay, that's one way. Sometimes too, there's someone, they are supposed to fix. Typical example. Another way in which bones go beyond. In the other one, they go beyond 206 bones. Another reason is that we expect that now, when we're in your mother's womb, we are having left and right frontal bones. Left and right frontal bones, and they were separated by somebody called frontal suture, otherwise some people call it metopic. M-E-T-O-P-I-C, metopic suture. Now, after birth, as air begins to blow over it, okay, it starts beginning to fuse. My friends, by age eight, it is completely fused. We expect that it is completely fused, except in some people, they have something called persistent metopic suture. It will still be present. In other words, such a person will reach adulthood or whatever, and to also have having two frontal bones, although we are told that in the adults, we have a single frontal bone. So that's also another way, failure of fusion, which are destined to fuse. Then we take the total number of adult bones going beyond 206. Okay, so that's also another good.
Now, we'll go through all the possible reasons why all these things will happen. Under example, there are some people, yes, we have 12 pairs of ribs. Ribs, 12 on either side of the body. Now, there are some people, and they are playing only these. Less people, they have supernumerary ribs. So that they have accessory. Ascending to baby C7, the seventh cervical degree. Okay, so it means that the total bones will go beyond 206 bones. They have cervical ribs as well. Okay, that is also another term that you should be aware of. These are some things which will make the total number of bones going beyond 206. There will be another reason. I'll explain that one to you as we move on. Okay, so that is, I mean, that one. Okay, that we are having all these sutural bones as well, also being, you know, present, okay, over there.
Now, if you have seen sutural bones confined to the skull only, then it also reminds me of something again. And this time around, yes, we are looking at some bones of the skull, especially the cranial bones, with something. Facial bones. So some bones on the skull, this time around, these bones, they are very close to the nasal cavity. They have around the nasal cavity, like in this manner. These bones, okay, they have this kind of air-filled spaces, which will help lighten the skull. They also serve as resonating chambers of sound. One thing is that it will help in some immune function. Why? Because they have to humidify the air. They have to condition the air before it gets to the alveoli of the lung. My friends, these guys, because they are around where we have the nasal cavities, around, then we call them pneumatic bones, and they have something called paranasal sinuses. So I understand that I want you to do it is paranasal sinuses. Pneumatic, pneumatic bones. The approach of the skull, but just that they have this kind of air-filled spaces. These air-filled spaces are around where you have the nasal cavity. What they are going to do is that because they are air-filled, they'll make the air buoyant. They reduce the weight of the skull. And as I talk, you know, I have this characteristic, very characteristic voice that I have whenever I have a cold. It means these guys have been inflamed. That's what we call sinusitis. Sinusitis. Now, so what bones, okay, can we say they are pneumatic bones? They are skull bones, but they have those air-filled spaces, having paranasal sinuses. And there's a simple mnemonic for you, that is, MESS. MESS. M-E-S-S. Now, whenever we say M, E, S, S, it will present a massive sinuses. But there are sinus, madrasound used to be present. So they are the maxillary sinuses. Okay, we'll be present. So...
Now, when I break this area, you see the air-filled. You can see it's very close and it's all cavity, air-filled area. When I break the same, you see that kind of cavity. Now, maxillary sinus is the largest cavity. The largest cavity. Then you also go to the ethmoid air cells. So we have ethmoid, ethmoid sinuses, or cells. Around, they also have frontal. Now, sometimes you see that especially for the males, because most males tend to have, you know, larger frontal sinuses compared to females. I told you that these guys, they lighten up that, they lighten up the skull. What they are also going to do is that they will say some kind of immune function, okay, by humidifying the air, purifying the air, warming the air to suit the body temperature. Males, we are more involved in, you know, dangerous activities. We hear a lot of things which are not very good over here. Okay, if you break this area, you see the sinus over the frontal sinuses. Frontal sinus, you know, is over here. Just one frontal sinus is over here. Now, the second largest, they also have the sphenoid. Sphenoid, sphenoidal, or sphenoid sinus. Okay, the tenth largest. The least one, the smallest ones are more important and point out air cells in there. Now, all these guys, they are just around, close to the nose. That's where we find them. Okay, so another, I mean, mnemonic for you is the frontal bone, the sphenoidal bone. We can say that they are pneumatic bones, although yes, we are still talking about bones of the skull. Okay, so that's also another useful thing that I want you to be aware of.
Now, the next bone type, okay, which we are going to look at, is what we call the so now, the fourth type, and something called sesamoid. Sesamoid. So we have some bones, they resemble sesame seeds. Some seeds, okay, so since they are called them sesamoid bones. Now, what's the uniqueness of these bones? Most of these bones, they are very small, except the largest one that we have in front of the tendons of muscles. Tendons of muscles, that's where they belong from. Okay, so that's one useful thing that I want you to be aware of, that these are small bones. They develop within tendons of muscles. One thing, two, that we find with these bones, these are some more bones, is that they don't have the right hand. Just like I told that the clavicle doesn't have medullary cavity. Sesamoid bones are also devoid of medullary cavities. Therefore, they will not be relevant in hematopoiesis, production of blood cells. They will not be relevant in that. Number two, I'll be explaining that one to you, and I'll use the long bone to show you. Now, normally, if you take a bone, the outer cortical bone, you will see that there will be something surrounding it, we call it periosteum. In that one, periosteum. Now, one unique thing is that erosion will have some blood vessels called periosteal arteries. And those arteries, they are very important in healing of bones, healing of bones. Periosteal arteries. Therefore, if you don't have periosteum and for that matter, multiple arteries, then whenever there's a fracture of the bone of such bone, then I mean healing of that bone will be very slow, will be very, I mean, uh, what do you call it, a humping. It won't go on very fast. Okay, so that's, I mean, one thing that I want you to be aware of. And for that matter, what about the patella? And whenever we say patella, if you look at this guy, that's the kneecap. Whenever you have the patella getting fractured, it will take months and months and months, several, I mean, period for it to heal. Practically, I mean, healing is not possible compared to some of these bones.
The bone becomes much facilitated. Okay, so that's one. Now, I told you that the largest small bone is this guy, we call it patella. And we said that this bone, they develop within tendons of muscles. Tendons of muscles, yes. And this bone, example, is this guy, okay, there's a patella and a tendon. Now, there are some very big muscles over here, there are four of them. So important quadriceps group of musculature. We understand these ones, these quadriceps muscles. Okay, before they transmit, before they transmit mechanical force, okay, for that matter, their tendon, or something called patellar ligament, onto what you call the tibial tuberosity. They will attach over here. What they are doing is that they have this guy over here, okay, before it were attaching here. So the tendon, within the tendon of the quadriceps muscle, we have what we call the patella developing in there. And what is it doing? It is increasing the mechanical advantage of the quadriceps muscles. So that's one thing that you have to be aware of, that you know, mechanical advantage is load over effort. We don't have this one to work so much to cause that kind of knee extension. Now, when you are walking, you flex. When you flex, starts like that, you decrease the angle. Then when you extend. So in walking, extension, flexion is very important at the knee joint. Okay, that is why we are having this patella, the largest small bone we have in the human body, patella, in the and transfer of the knee joint, okay, over here, to help increase the mechanical advantage. Now, one thing is that they also help protect, you know, the tendon. Okay, also they will do that. But importantly, what will happen is that if this one will not be around, then what will happen is that there will be more compression, compressive force, causing increased arthritis, the incidence of arthritis at the knee joint. Okay, so one thing I want you to be aware of is that quick joints is most susceptible to arthritis. Your answer is the knee joint because we have, we use it more in walking and all that, locomotory movement. Then it means that this area is very okay. So what about this muscle contracts? Because of what, what you have the patella, then the compression and the knee joint is minimal. Okay, so that arthritis is also reduced. The incidence is reduced. Okay, also increasing the mechanical advantage. So that of course, you don't have to wear too much. Okay, for instance, if you are climbing stairs and all that, it means that if you don't have patella, that your walking movement, whatever, especially when you are.
Climates test will be very, I mean, difficult, and it may be prone to frequency of arthritis. Okay, that's good. Now, I told you that it is not only the kneecap that's the classic example of what we call there, there's a small group. But you also have another small bone, but here, although it's a short bone, that is what we call the patella. The patella bone that tendon is what we call the tendon of flexor copiae or nice sesamoid. Okay, very important. So another way that we can understand, okay, these are small bones that they serve as something called anatomical pulleys. Anatomical pulleys. Another name, another, I mean, way we can describe these guys by increasing the mechanical advantage, reduce natural joint protection, you know, knocking off tendon. Okay, so what we are saying is that they, I mean, serve as an anatomical pulley, p-u-l-l-e-y. Now, when you are in the scenario, you learned about pulleys, okay? So that was, I mean, what we are talking about, anatomical pulleys. Now, have you seen that? Okay, these are small bones. There are other small bones that we have. Yes, there are no names we don't talk about them. So another way in which an adult, the total amount of bones will go beyond 206, will be the presence of additional sesamoids. Now, there is one sesamoid which you call it fabella. Fabella. Okay. Now, it's present in about 10 to 10 percent of the population. We call it fabella. Now, if you look at those are the knee joints, I can see the patella here anteriorly, and then other crucial aspects, I see the popularity of the USA. Okay, okay, up over here. Now, this is the femur. That's not the end of the femur. It's also a long bone. So that's the end of the femur. Represents with something we call them condyles. We come to these condyles. Now, those condyles, the one towards the lateral aspect, how do I know? I know because over here I see the fibula. Fibula is the lateral bone of the leg. The medial bone of the leg is this big guy which we are called the tibia. And so if I go upwards, okay, that's the fibula. If I go across towards the posterior aspect of what you call the lateral femoral condyle, then I see that there's something that's another bone developing over here. And this time, that bone develops within, you know, another muscle. Okay, and that muscle, okay, the tendon of that muscle is what we call the medial head of gastrocnemius. Now, there's one muscle. Don't worry so much about these names. You will come to them. Okay, if you look at the is. And therefore, when I go to the opposite side, okay, where I have the little two negative 20, then what will happen is that if I go across, now look at this. I mean, mostly we tend to see them more in Asians. Among Asians, it's very predominant over there. Okay, very common feature that we find. Most of the time, they don't present with any issue. But sometimes some people may be having pain over there. Okay, fabella, you know, pain. And whenever there's that one or something, it could be that kind of compression on one nerve which runs laterally. You divide in a public health visa, and it runs laterally. Okay, so from the sciatic nerve, then we have what we call the tibial nerve. Right? Now, we have the common peroneal nerve, and then they will mention that one or the people are common peroneal nerve. Anything peroneal has to do with the fibula. So get to understand that. So that one to make compress it. Sometimes just some analgesics that will be prescribed if there's that too much pain over there. Some, I mean, anesthesia can also even happen over there. But one thing is that if you become very persistent, you are feeling more pain, more pain, then they may be the need that will remove this bone. And the removal of this bone will therefore be called parableectomy. Okay, so that is, I mean, you have to be, I mean, aware of. Now, not only that, even sometimes the plasma tendon that we have with what you call the, I mean, popliteus. There's another, I mean, muscle that we call popliteus. Okay, we get to know that there will be another bone also developing in there. That one we call it semella. Semella. Okay. That one too also be developing in there. That one is also around, yes, that same area. Okay, lateral aspect around here. Okay, where the popliteus were, I mean, b. So around here, then we have what we call. Okay, okay. These are. And that one is the incidence is less than two percent. Okay, in less than two percent of the population. So it means that if I'm having such a person and have more of these bones, even there's one muscle which we call it peroneus longus. Okay, so if you look at this muscle, yes, this big, this muscle over here, it runs all. We call it peroneus or fibularis longus. We will come toward you. We understand the domain creature. Okay, so around that, that's of course going laterally. And there's one wrong way is also playing. If you look at this guy, the lateral aspect, right? So this is the lateral aspect. Sometimes we see that bone also developing in here. So we call it os peroneum. And now I've told you that anything peroneal has to do with the fibula. Like, okay, in the lateral aspect. Okay, this week. So we can have all these things. Now, especially you may also even have, you know, distance around that, I mean, hollows, they're great too. Okay, so all these guys, eh, I mean, sesamoids of the hallux. Okay, there may be two of them around. And all these. So you can have some of them in that they get the tendons, they send each other, they get the tendons, they're standing in today, they get, okay, as well of the toes. So all these guys, okay, will be present, you know, over there. So please be aware that we have whenever someone is having a lot of someone doing this, yes, then it means that the person will be having more, more way beyond the 206 bones that we find in the airport. Okay, so that is one thing that we have to be aware of. Now, for that reason, this reason, let me be quick and say this. We are told that a newborn has, yes, more bones. Yes, the number will have more bones. Yes, newborn. Let's say three months old. Then I have someone who is, let's say, two years old. Then I have someone who is, let's say, 30 years old. Then which of them will have more bones? I'm sure you are confused. You will say that it is the three-year-old because the newborn has more bones. But I've explained to you that there are two ways in which bones form. One of them is by what we call intramembranous ossification, and the other is by endochondral ossification. Now, what it means is that most of what you call the fetal skeleton, and for that matter, the newborn, will become cartilage. Mainly hyaline cartilage will be predominant over there. It is later that these ones through the ossification centers, they'll be converted gradually and gradually to become bone. So it means that you don't want just say that yes, is, I mean, I mean, the newborn. No, no, no, no. It is later that later they'll get ossified. Let's say by two years, someone's ossification has taken place. But when these bones get to us, but they'll be separate. It's later that they have to fuse to form single bones. That is why I will take the two-year-old, okay, to be the one with the most numerous, you know, bones. Okay, so that is, I mean, one thing that I want you to be aware of. Now, if you have seen that, okay, that was the, I mean, it says someone moves. Then there's another bone type that you have to be aware of. There's another bone type, and that other bone type, you fail to put them as, you know, particular places. You have 18, and therefore we call them irregular bones. Irregular bones. Irregular bones and foreign. Yes, irregular bones. Already I've told you that some of the facial bones are irregular. Regular. I told other calcaneus is irregular. Okay, the heel bone. This guy, that's one half of it that I'm taking, it's irregular. Okay, the heel. Yes, irregular. Irregular bones is what we call the vertebrae or the vertebral column. Demonstrate that one for instance. If, if I say this is okay, then what we are saying is that it's just having these kind of processes standing out of it. Okay, so all these, it makes it what, irregular. Okay, so this is an irregular, I mean, these are irregular bones that we are talking about. So now, having seen these kind of, I mean, bone types that we have, then the next term, okay, that I want you to also be aware of is that we want to look at how this kind of bone is. Okay, so let's now look at these kind of bones we've been talking about. So the whole parts, totally, I told you that most of energy will be put or will be spent on what you call me belonging for us to really understand all that we have to be aware of. So assuming I have this at the long run, let's see. I assume there's a long bone. Okay, assuming there's a long bone. That one thing that we've come to understand is that the long bone will have a diaphysis. Okay, now the diaphysis is the one that we are calling it that is. So this is the shaft. All the diaphysis. Okay, now we appreciate why we call it diaphysis. Now, one thing you should be aware of is that normally the ends of the bones are epiphysis. One end of the bone, this end of the bone, okay, is called epiphysis, and then the opposite end of the bone, yes, this is also epiphysis. With respect to a reference point, that this one becomes proximal epiphysis. Is that around here? Let me see over here. Okay, we find. [Music] This one is called diaphysis. Now, whenever we say diaphysis, it's the same as epiphyseal plate. Please, epiphyseal plate is the same as epiphyseal plate. So precisely, the area for me to call it epiphysis, actually, the one present above it will be the epiphysis. Now, that region below the epiphysis, that means have gone beyond the epiphysis, becomes what we call the metaphysis. So let's say this area is the metaphysis. Now, for this reason, I can say that the metaphysis is more or less like part of the epiphysis. So we say that the epiphyseal end of the epiphysis is metaphysis. I hope you understand what I'm saying. Epiphyseal and metaphysis. It's in closer to the epiphysis. So the epiphyseal end of the epiphysis is metaphysis. Okay, so that's one huge photo. Now, I'll come to it. But for now, you should know that it is this metaphysis, this region where we tend to find more of, you know, osteomyelitis taking place, especially in children. We understand why. [Music] Means that if you look at the long bone, it's going to have a diaphysis inside the body or the shaft, then it's going to have its ends by way of the proximal epiphysis and distal epiphysis. But when I take the epiphysis, so that's actually the real epiphysis we are talking about. And why? Because it's having a growth plate over there. That growth plate, which is supposed to grow, healthy elongation on the long bones, which will become exhausted with time. Okay, I mean, because of high levels of estrogens, a lower level of testosterone in females, it had to, you know, fuse earlier compared to that of the male. Now, with time, this epiphysis will become something we call epiphyseal line. Epiphyseal line. Okay, so please understand that one for us. It fuses to become an epiphyseal line. Or it's a form. Okay, so either we say fusion of epiphyseal plate or formation of epiphyseal line. That is, I mean, they are synonymous. Okay, whatever we can use. That is. Now, before this one, you know, it's after the epiphysis that we are saying metaphysis. Okay, so that was, I mean, what we see is that these bones, they form joints. They form joints, and that is why that portion of the bone is forming joints. We call the articular surface of the bone. So assuming this portion of the bone is going to form joints, the bone doesn't form joints just like that. It has to be covered by some cartilage. So I'll give you this area. It is covered by some cartilage, and that cartilage, okay, is what we call the cartilage. Now, anytime you hear the word articulate, it has to do with a joint. Or arthrosis, it has to do with joints. Okay, so sometimes that's why inflammation on the joint, you call it arthritis. Okay, so that is, I mean, one thing you should be aware of. Thus, hyaline cartilage is devoid of something we call perichondrium. We come to understand that perichondrium is connective tissue. It is actually a dense irregular connective tissue, and it's supposed to have nutrients and downward blood vessels that are supposed to nourish through diffusion, nourish this kind of cartilage. We talked about including hyaline cartilage. Now, those guys, articular cartilage is a hyaline cartilage, only that it doesn't have perichondrium. Okay, so that's one useful thing I want you to be aware of. We have to explain all these things. Okay, their usefulness later. But one thing that we find is that around the epiphysis, okay, of the bone, then this kind of connective tissue over here, let me say this, there's this connective tissue around. So where I'm indicating with this red, the connective tissue that surrounds bone, we call it periosteum. Periosteum. Just like my marker, you can see this. Let's get in tone. So if the diaphysis of the bone, then it's having this kind of sticker around it. That's thicker. That connective tissue made of dense irregular connective tissue is the periosteum around the bone. Peri means around, around the bone. And this, through the same periosteum, that blood supply will get the diaphysis of the bone. So supplying what we call the inner to outer portion of the cortical bone, okay, of the compact bone around, as well as the medullary cavity. You get to know that the space over here, cavity, will be by what we call periosteal arteries. Now, it is the same periosteum which carry pain fibers. Okay, carry pain from the bone. So anytime you like feeling that kind of bone pain, because the nerve endings, okay, in what we've got the fibers in what we call the periosteum have detected it. Okay, so that is why it's a useful term that I want you to be aware of. Okay, so the arteries will invade. So those arteries, okay, from the side, will invade the work. So for instance, if I'm supposed to use this one to shoot, so the arteries will supply this way from this side, sorry, and this one, we call that periosteal arteries. They will supply the outer. [Music] Let me make it this way. Up to here. Okay, they'll supply what we call the outer one-third portion of. That's what is going to happen. Okay, so they will invade it like that. Now, this thicker that I put on this marker, now there should be something to glue it to the bone. There should be something, and that is that one is what we call Sharpey's fibers. So gradually we are going into the bone. Okay, this is what we call the Sharpey's fibers. One thing I want you to be aware of is that if [Music] then it means the inside lining, the medullary cavity, there should also be another covering in there. My friends, that one is called endosteum. Endosteum. So assuming the inside, the inside, okay, the covering from the inside, that one is called endosteum, my friends. Unlike the previous jumper, it's made up of dense irregular connective tissue. That of periosteum is rather having something called reticular connective tissue forming that kind of framework. Okay, to support the growing cells, why? Because over there, we are going to have red bone marrow. And that coming through. Before medically covers. So the cavity over here, let me see this one. Now, I've already told you that the medullary cavity in the young person will be filled with something we call red bone marrow entirely. And that red bone marrow is will be relevant in something we call hematopoiesis. Hematopoiesis. But as you age, this cavity, mainly for the diaphysis of the bone, will be filled by what we call yellow bone marrow. The storage site for fat. Okay, so that is one important thing you should be aware of. Now, if I've mentioned red bone marrow, then I have to be quick and tell you that in the ends of the bones, however, in the ends of the bones, so from here, the ends of the bones, the ends of the bones, rather, will be having what we call, I mean, red bone marrow. It's having spongy bone. Okay, which will be having red bone marrow. It's not going to compartment, but there will be a shell of compact bone around it, mainly having hollow spaces in the light sponge. So we've got to explain.