1b.3 Vertebrae by Region.pdf

[00:00:06] >> This presentation will examine specific characteristics of the vertebrae region by region. At the completion of this, you should be able to distinguish a cervical from a thoracic from a lumbar vertebrae based on these characteristics. As we all know, the sacrum is going to be significa...

[00:00:06] >> This presentation will examine specific characteristics of the vertebrae region by region. At the completion of this, you should be able to distinguish a cervical from a thoracic from a lumbar vertebrae based on these characteristics. As we all know, the sacrum is going to be significantly different because it consists of fused vertebrae. [00:00:34] This slide provides an overview of all seven cervical vertebrae. We often, in PT, break down the cervical spine into the upper cervical, which actually consists of C1, C2, and the occiput, or the base of the skull, from the lower cervical spine, which is our C3 through C7. We will also notice C7 has some of its own unique characteristics. [00:01:07] This example of a cervical vertebrae allows us to explore the typical characteristics of the cervical vertebrae. First, if we look at the body, the body of a vertebrae will always be the largest bony portion. However, the body of the cervical vertebrae is small compared to the other region. [00:01:29] We also notice all vertebrae have a spinous process, but a key in the cervical vertebrae is that they are short, and they are also what we call bifid or split. So you will always notice a little space between the two ends. The vertebral foramen or vertebral canal is very large in the cervical region and it is triangular shaped. [00:01:53] As we will see later, the spinal cord is very large in the cervical region which accounts for this larger space. As with all vertebrae, we have transverse processes on the cervical vertebrae. However, several unique characteristics. First, the cervical vertebrae transverse processes have an anterior and posterior tubercle. There also is a small opening or the transverse foramen in all of these cervical vertebrae. [00:02:26] From the level C6 up through C1, this is where the vertebral artery passes through. We also will notice that the articular facets in each region have a unique line up. In the cervical region, the superior articular processes face posterosuperiorly. In other words, they extend upward with the articular surface facing posteriorly. [00:02:56] Whereas the inferior articular processes, which are not visible here, they would be extending down this way, their facettes are oriented anteriorly or facing forwards. We also do see what we call some uncinate processes. This is not as important or significant but there's usually an up sloping on the lateral edges of the body. [00:03:22] These can be more significant as individuals get older. This slide provides a summary of what we just discussed about cervical vertebrae characteristics. Including the body, the vertebral foramen, the characteristics of the transverse processes, the articular processes, and the spinal processes. Feel free to pause the video here and read the details. [00:03:49] Here we see the cervical vertebrae from a lateral view, and then a plain film radiograph of the same perspectives. So a couple pieces to note, because of the orientation of the articular facets, from a lateral view, we see these facet joints, or zygopophyseal joints, more on that coming up, that they tend to have an anterior-superior alignment, somewhat of a diagonal. [00:04:20] And you will see that in the radiographs as well. What you will also notice in the radiograph, and much more on this when we get into our radiology, you will notice that because the discs are made of fibrocartilage, they appear as spaces between the vertebral bodies. We will take more time to explore the radiographic details of the cervical vertebrae later. [00:04:48] The upper cervical vertebrae, C1 and C2, are considered atypical cervical vertebrae because they have several unique characteristics. C1, you will typically recognize because it looks more like a ring than a typical vertebrae, it has no body. Instead, we will see a ligament coming across, which we will talk about in an upcoming lecture, that will help to stabilize the extension from C2 which is the dense. [00:05:23] What we also see on the C1 or Atlas vertebrae is that the superior articular facettes are very large and face directly superiorly because they articulate with the condyles of the occipital bone. We will talk about this in a later lecture, but this allows primarily a flexion extension of the skull. [00:05:51] Essentially, you're nodding. C2, or the axis vertebrae, also has some unique characteristics. First, you will recognize it because of this great bony extension or the DENS or odontoid process which extends upward and forms a pivot joint with the anterior arch of C1. This as you could imagine, allows rotation, essentially turning left to right of the upper cervical vertebrae on C2. [00:06:30] You will also notice that C2 has a very small transverse process, whereas C1 has essentially no transverse process. It has only what we refer to as the posterior tubercle. The key with these two, you should be able to recognize C1 and C2 very uniquely based on these characteristics. [00:06:55] And once again, in summary, C1, bony-wise, Is typically going to look like a ring. And C2 is always going to have a large almost spike sticking up out of the body, which is your dens. The final atypical cervical vertebrae is C7. And you may notice right off, one of the factors is the spinous process is long, extending directly posteriorly, and it is not bifid or split. [00:07:32] It more so resembles the spinous process of the upper thoracic region. We also will notice while it still has transverse foramina, they are very small because the vertebral artery does not actually pass through these foramina. One of the key pieces that you will note with C7, as we noted that the spinous process is more like the thoracic vertebrae. [00:08:00] Any vertebrae in either the very beginning of the region or the very end tends to share characteristics with the next region. You will see this as well when we get to the lower thoracic vertebrae. As we examine the thoracic vertebrae, we will notice that some of the key characteristics relate to the fact that all thoracic vertebrae have a rib associated with them. [00:08:32] But first, as we look at the body of the thoracic vertebrae, we will notice that they are becoming larger compared to the cervical. And as you move from T1 down to T12, they will continue to become larger. We will also notice that the spinous process in the thoracic region are very long and tend to be pointed posterior inferiorly. [00:08:59] The vertebral foramen in the thoracic region, or the vertebral canal, we will notice is round. That is different from what we saw in the cervical where the cervical vertebrae had a more triangular shaped vertebral foramen. We will also notice differences in the transverse processes. First the transverse processes in the thoracic region are much longer, and they are also posterior to the articular facets. [00:09:29] In addition vertebrae T1 through T10 will have a small facet on it that articulates with the tubercle of the rib. We will also notice the articular processes tend to extend directly superiorly and inferiorly. With their articular facets or the articular surface directed directly posteriorly or directly anteriorly. Making these facet or zygapophyseal joint oriented almost perfectly superior inferior. [00:10:08] And finally, one of the most key characteristics to the thoracic vertebrae is that each body will have a costal facet. Now, due to the alignment of the ribs, most bodies in a typical thoracic vertebrae will actually have to costal facets sometimes called demifacets that will articulate with the ribs. [00:10:32] Much more on how the ribs articulate coming up. But if you are looking to identify a vertebrae, your cues to the thoracic region are going to be these demifacets on the body. We can take another look at the thoracic vertebrae from a superior view. And again, we will notice those thin and superiorly directed articular processes. [00:10:59] You can also see there's sort of a little flat spot on the posterior lateral aspect of the bodies. And that is your costal facet or demifacet. Once again you can also notice the size and alignment of the transverse processes that they are posterior to the articular facets and intervertebral foramen. [00:11:23] And finally that we see one direct clear posterior-inferiorly directed spinous process. On this slide we note the characteristics of the cervical vertebrae. And again, taking each component that we just talked about, feel free to pause here if you would like to read in more detail to review these characteristics. [00:11:57] Often the first thing that we notice about lumbar vertebrae is the size of the body, both in a cross section, as well as from an anterior or lateral view. The bodies are wide and tall, and this accounts for the fact that they do carry much of our body weight. [00:12:18] We will also notice spinous processes are again short and directed almost directly posteriorly. The vertebral foramina, or the vertebral canal is now triangular-shaped again. So both the cervical and lumbar vertebrae have this Somewhat triangular shaped foramen whereas the thoracic has a very round foramen. Our transverse processes in the lumbar region are short and directed directly laterally. [00:12:54] They also are once again anterior to the articular processes. The articular processes now face medially and laterally. So what we will see is that the superior articular processes, the surfaces face medially, whereas the inferior articular processes, the articular surface is going to face laterally. What we will notice as we talk about movement is that this combination tends to limit rotation in the lumbar region. [00:13:32] One other key process to note on the lumbar vertebrae is what is known as the mammillary process. These are essentially a little bump that sticking off the inferior portion of the superior articular processes. Why we are interested in these very small mammillary processes is because this is where our multifidus muscle attaches. [00:14:00] We will talk a lot more about multifidus as we get into the muscles, as well as, as you get into your musculoskeletal content. This slide just provides another superior view of the lumbar vertebrae, where you can really appreciate the size of the body as well as the very triangular vertebral foramen. [00:14:24] We can again see the very short components of the transverse processes. Some sources referring to them as costal processes even though the lumbar vertebrae obviously do not have ribs. You can also note the very short posterior spinous process. This slide provides another written summary of what we have discussed about the different characteristics of the body, the foramen, the transverse processes, articular processes, and spinous processes of the lumbar vertebrae. [00:14:59] Again, feel free to pause, to read through, and review. The sacrum is essentially five fused vertebrae with a kyphotic curve that in the human form essentially one bone. However, we can identify components of the sacrum that relate to our typical vertebral structure. First of all, instead of having intervertebral foramen where the spinal nerve roots emerge, the sacrum has ventral or anterior sacral foramen. [00:15:42] Essentially little holes on the anterior surface, both on the left and on the right, as well as having ventral sacral foramen. So again, small holes on the posterior on both the left and the right where sacral level nerve roots will emerge. We also see the superior articular processes which parallel the articular processes the superior articular processes of any vertebrae. [00:16:15] And these will articulate with the inferior Articular processes of the L5 vertebrae. We also see the superior aspect of essentially what looks like the sacral body, which this will also form the L5S1 joint with the lumbar vertebrae. We note, the anterior ridge of the sacral body is what we refer to as the sacral promontory. [00:16:49] With the sacrum, we don't see the typical transverse processes, but what we see instead are what are called the wings or the ala. Which are the broad components on either side of the sacrum. On each of these wings or all up, there is another articular surface which is typically referred to as the auricular because it sort of shapes like an ear. [00:17:18] And this is an articular process that is covered with cartilage that will articulate with the bony ilium or the pelvic bone. This is what composes the sacroiliac joint that we will talk about more when we get to arthrology. We will also notice that on the posterior, we have what essentially parallel are spinous processes, which is known as the median crest and spinous tubercles. [00:17:49] And finally, the inferior opening of what was the vertebral canal is known as the sacral hiatus. So this opening down at the inferior level of the sacrum is the sacral hiatus.