 Good day everybody. This is Dr. Sanjay Sanyal, professor of department chair. This is going to be a demonstration of the ribs. So we have arranged the ribs sequentially. On this side of the picture you can see these are the ribs on the left side and on this side the ribs are on the right side. Let's now come down to the quick classification of the ribs. The ribs are traditionally classified as true ribs, false ribs and floating ribs. The first, second, third, fourth, fifth, sixth and seventh ribs. These are classified as true ribs. Why they called true ribs? Because the anterior portion of the ribs after that the costal cartilage it articulates directly with the sternum. These constitute the sternocostal articulations. The eighth, ninth and tenth ribs are called false ribs because they don't articulate directly with the sternum. Their costal cartilages articulate with the costal cartilage of the seventh rib. That's why they called false ribs and they constitute what is known as the intercontral articulation. And the 11th and the 12th ribs are called floating ribs because they do not articulate with the sternum at all. But there are other factors which I shall mention just a little later. The anterior portions of the ribs are replaced by costal cartilages. And they constitute the costal contral junction and after that they articulate with the sternum as we have already mentioned. The first rib articulation with the sternum is the same controsis. There is no movement. While the other ribs, there's a synobia joint and there's a small degree of movement which is possible until it is classified in old age. Having mentioned that, now let's take a look at another classification of the ribs. Now we shall talk about what is known as the typical ribs and atypical ribs. So let's focus on the left side and let's pick up a typical rib. This is a typical rib. Which are the atypical ribs? The first, second, the 10th, 11th and 12th are the atypical ribs, which I shall mention just a little later. Let me mention the parts of a typical rib. A typical rib has got a head, then we have a neck, then we have a tubicle, then we have an angle. Then we have the shaft. Let's go a little deeper. Let's take a look at the head itself. A typical rib head has got two parts, two facets, a superior facet and an inferior facet with a crest in between. The superior facet articulates with the vertebral body above, the thoracic vertebra above, and the inferior facet articulates with the vertebral body the same number. So if this is the sixth, it articulates with the sixth thoracic vertebra. To explain this further, let me just go to a typical thoracic vertebra. So this is a typical thoracic vertebra that I focused on in front of you. You can see this typical thoracic vertebra has got two demi facets, a superior and an inferior. The superior demi facet articulates with the same rib and the inferior demi facet articulates with the inferior rib. So therefore, each rib articulates with two vertebrae and each vertebra articulates with two ribs. This is what constitutes the costo vertebral articulation. So that is about the head of the rib. Now let's come to the neck of the rib. The neck is this slightly flat and a slightly constricted portion after the head. We all know in anatomy any structure after the head is always the neck. So therefore, this is the neck of the rib. Then we have the tubercle of the rib. The tubercle also has got two parts, a medial portion and a lateral portion. The medial is the articular portion which articulates with the transverse process of the vertebra of the same thoracic vertebra. And that's what constitutes the costo transverse articulation. So let's come back again to the same thoracic vertebra. We see that this is the transverse process. And there's an articular surface here. This is what constitutes the costo transverse articulation, the tubercle of the rib articulates with the transverse process. The nonarticular part does not articulate. Then we have the angle of the rib. The angle of the rib is actually a distinct angulation that we can see when we look at the chest from the posterior aspect after removing all the muscles, especially the deep muscles of the back, namely the aterospinae muscle. And once we remove the aterospinae muscle, we find that the lateral slips of the iliocostalis muscle, which is a part of the aterospinae are all attached along the angle of the ribs. And we can see it as a distinct straight line all along the length of the back of the chest wall. That can be seen in an actual cadaver dissection. The rest of the rib is the shaft of the rib. And as I mentioned, the anterior portion continues as the cartilage. In old age, the cartilage can get calcified. And that gets articulated with the sternum. Now let's take a look at the inferior border of the rib. If you take a look at the inferior border, you find that it is quite sharp. That's how we determine which is the inferior border of the rib. In contrast, the superior border is rounded and blunt. And just inner to the inferior border, there's a shallow ridge and a groove. This is called the costal groove. And this costal groove shelters the neurovascular bundle, namely the vein artery nerve going from above down in that order. The neurovascular bundle is located in the costal groove. And therefore, whenever we are doing any intercostal procedures, we have to take care to safeguard the neurovascular bundle. And therefore we have to be far from the inferior border of the rib above when we are doing any intercostal procedure. So these are the parts of a typical rib. Let's mention a quick few clinical correlations pertaining to a typical rib. The ribs can get fractured by compression force like the way I'm doing with my finger now. Like for example, a person is driving without seatbelt and he has an accident. The chest gets compressed against the steering wheel and the rib gets compressed like this. Therefore, the middle portion of the rib is the one which undergoes a springing motion and that's where it fractures. And this side of fracture is located at a region of the rib which is called the postrolateral bend of the rib. The postrolateral bend is not to be confused with angle of the rib. The postrolateral bend is where the rib makes a curve from the posterior to the lateral aspect of the chest wall because that is where the force is exerted. And the fourth through the ninth ribs or roughly the middle portion of the chest, the ribs are the ones which are most likely to fracture. If more than two ribs, adjacent ribs are fractured in two or more places, then we get what is known as a flail chest which is a very serious condition when the chest expands, this portion of the chest goes inside and that can lead to respiratory embarrassment. The first rib is rarely fractured because it is predicted by the clavicle. If it does fracture, it fractures at the groove for the subclavian artery and the subclavian vein which I'm going to mention just a little later because that is the weakest part of the first rib but it rarely fractures as I've already mentioned. A rib can be used for autologous bone graft when we have to replace bone for example in the skull after skull surgery or after trauma because the rib consists of cancerous bone. When we are doing a thoracotomy, we split the periosteum on the surface of the rib in posterior lateral thoracotomy and we lift up the periosteum and we resect that portion of the rib under the periosteum that is called subperiosteum resection of the rib by means of an instrument called a rib shear and rib respiratory. And after we have done the surgery, we just close the periosteum and the rib can grow back because of the periosteum is intact. Consider these other ribs are not very common. We can have bifid rib which is present only in about one or 1.2% of the population. We can have a cervical rib, we can have a lumbar rib in the conditions which are known as a cranial shape of the vertebral column or the caudal shape of the vertebral column. So these are a few points about the typical ribs. Now let's mention a few quick words about the atypical ribs. So let's start with the first rib itself. So now we have come to the right side. So we will pick up the right first rib. The right first rib is the most atypical. It is flat. This forms the boundary of the thoracic inlet and the surface of the rib makes an angle of approximately 60 degrees with the horizontal. That is how the thoracic inlet is oriented. We notice that the tubical and the angle of the first rib are the same. This is the tubical and the angle. More notably, the first rib has got a small elevation here. This is called scalyne tubical. On this side is the subclavian group for the subclavian artery and here is the group for the subclavian vein and in between the two is the scalyne tubical. Behind the subclavian artery we have the attachment for the scalyneus medius muscle. So therefore the scalyneus artery goes like this. It goes between the scalyneus anterior and the scalyneus medius. It enters through the scalyne triangle. So therefore the first rib forms the boundary of the scalyne triangle. And this is where we can palpate the subclavian artery against the surface of the first rib. If we dig our finger deep inside in the supraclavicular fossa. The point to be remembered here is that the subclavian artery and the brachial plexus can get compressed in the scalyne triangle. But the subclavian vein does not get compressed because it is outside the scalyne triangle because scalyne tubical is here. This is a small elevation which marks the site of attachment of a few fibers of the first digitization of the serratus anterior muscle. The bulk of the serratus anterior muscle is attached. The first digitization is attached to this tuberosity for the serratus anterior on the second rib. And after that we know the serratus anterior has got attachment by means of multiple digitations to the third fourth up to the ninth ribs. That's the features about the atypical first rib and the atypical second rib. The first rib, the 10th, 11th and 12th ribs, the head has got only one articular face. Because the first rib articulates only with T1. T1 thoracic vertebra does not have demi-facet. It has got only one articular face. And the T 10, 11 and 12 has also got only one articular face. So therefore the 10th, 11th and 12th rib heads also have got only one articular face on the head. And I have shown the 10th, 11th and 12th ribs on the left side. So that's how they are also atypical. And to explain this better, I have kept the 10th, 11th and 12th thoracic vertebra in front of us here. So this is the 10th, this is the 11th and this is the 12th thoracic vertebra. We see that each of them have got only one articular face. The 10th thoracic vertebra articular face is at the junction of the body and the pedicle. The 11th and the 12th, the articular facet is on the pedicle itself. We know this is the 12th one because we can see that the superior articular facet of the 12th rib is in the coronal plane and the inferior articular facet is in the paris-jaddle plane. So therefore this is the one which articulates above with T 11 and below with L 1. Another point about the atypical rib is that the 11th and the 12th ribs, which I'm showing on the left side, there is no distinct neck and there is no distinct tubercle. As we mentioned just a little while back, these are the false ribs, the 8th, 9th and 10th. 8th, 9th and 10th ribs, the tubercle, if you take a look at the tubercle, they are more flat because they form a sliding type of costotransverse articulation. In contrast, the tubercle of the other ribs, the true ribs, that's the upper ribs, they are more rounded because they produce a rotatory type of costotransverse articulation. So therefore the upper ribs from 1 to 7, they are responsible for a slight rotatory movement on deep respiration and they increase the thyroposteía chest diameter and that movement is called the pump handle movement. So the upper ribs are responsible for pump handle movement they increase the antyropostea diameter. The lower ribs the 8th, 9th and 10th, they slide on the transverse process, therefore they increase the transverse diameter and that movement on the ribs is called the bucket handle movement. So the lower ribs are responsible for bucket handle movement, they increase transverse diameter of the ribs. So these are a few points which I want to mention about the typical atypical ribs, their features and their clinical correlations. Thank you very much for watching. Dr. Sanjay Sanyal signing out. Please like and subscribe to this channel. If you have any questions or comments, please put them in the comment section below. Have a nice day.