 What are the features of a typical cervical vertebra? For that, let me pick up a typical cervical vertebra. We can see this for MN here, these are the transverse for MN. And this gives passage to the very important artery, which supplies the posterior part of the brain, that is the vertebral artery. It goes from the sixth, fourth, third, second, first, up. The next important feature of a typical cervical vertebra is the bifid spinous process. And we can see that the spinous process is bifid. It's especially bifid in the case of the second one, but all the spinous process will be bifid. And the seventh vertebra spinous process is the largest. That's why C7 is referred to as the vertebra prominence. The third important feature of a typical feature of a cervical vertebra is the hook-shaped process on the lateral margins of the upper part of the vertebral body. And that is referred to as the anchors. This forms a unique joint with the vertebra above, and that is known as anko-vertebral joint, which in contrast to the rest of the body, which forms a cartilaginous joint, the anko-vertebral joint is a synable joint. So, these are the typical features of a typical cervical vertebra. Okay. So, I'm holding in my hand the atlas and the axis. So, this one is the atlantoaxial joint in the middle. It's the median atlantoaxial joint, which is formed by the dense of the axis articulating with the anterior arch of the atlas. It is held in place by a very strong ligament which goes like this. And that is known as the transverse ligament of atlas. And that is what holds the dense in its place. And this transverse ligament of atlas is very important in maintaining the integrity of the median atlantoaxial joint. Additionally, we have the two lateral atlantoaxial joints formed by the articular processes. One on this side, another on this side. This atlantoaxial joint is the one which gives you the side-to-side movement. And that is the reason why this is called the axis, because the dense acts as an axis around which the atlas rotates. Now, let's come to some important clinical correlations pertaining to the axis and the atlas. We can have hangman's fracture. When a person is hung by the neck, the seat to fracture just posterior to the transverse for MN. This is the place where the fracture occurs. And as a result of which, the cervical vertebral column gets kinked. And that's what produces injury to the spinal cord and results in respiratory arrest. That's what hangman's fracture is. This is a natural X-ray of the cervical spine to show a hangman's fracture of C2, axis vertebral. We can have another fracture pertaining to the dense itself. The fracture can go through the root of the dense, in which case the dense gets separated from the rest of the vertebral. The problem with the fracture through the root of the dense is that the arterial supply to the dense runs like this, where my probe is pointing. So if the fracture occurs at the root of the dense, then this portion of the dense loses its blood supply. And it undergoes what is known as avascular necrosis. There can be another fracture of the dense, and that is through the body of the dense. The body of the dense fracture does not have this problem of avascular necrosis because the blood supply to the dense is spared. So we can have two different types of fracture, root and body of dense. So these are some clinical correlations pertaining to axes. Now let's take a look at the atlas. When there's a crushing injury from top, then the atlas can fragment in four segments. One, two, three, four. And the four pieces when they move out. And that is known as a burst fracture. More specifically Jefferson burst fracture. So that is with pertaining to the atlas. This is a CT scan to show Jefferson burst fracture of C1 atlas vertebra. The type of injury that we can get in the cervical vertebrae as such is what is known as flexion injury. If the cervical spine gets hyper flexed, it can move, the vertebra above can move on the vertebra below. And that is known as a translation. And depending on the severity of the movement, it has been classified as stage one, two, three, four. This is a lateral x-ray of the cervical spine to show stage three translation of C6 over C7. In the fourth stage, if you take a close look at the articular facet, in the fourth stage the articular facet can jump. If you look carefully. If this is the articular facet, it can jump. That is the fourth stage. And that is known as facet jumping. Like a train which has jumped from the railway tracks in derailment. That is called jumping the rails. So here also when it jumps like this, it's called facet jumping. So that is what you can get in flexion injury. The reason why cervical spine is more prone to injuries is because of its mobility. So therefore cervical injuries, flexion injuries and cervical spondylosis is more common in the cervical region. Thank you for watching. If you have any questions or comments, please put them in the comment section below. Dr. Sajja Sanyal signing out. Have a nice day.