IB Vertebrae Osteology PDF

[00:00:05] >> Before we go in detail for the vertebrae of specific regions, we will take a quick overview of the spinal curves and some general characteristics of vertebral structure. The human spine consists of 33 vertebrae. 7 of these are in the cervical region, or the neck, 12 are within the thor...

[00:00:05] >> Before we go in detail for the vertebrae of specific regions, we will take a quick overview of the spinal curves and some general characteristics of vertebral structure. The human spine consists of 33 vertebrae. 7 of these are in the cervical region, or the neck, 12 are within the thoracic region, or the upper back, as we sometimes talk about it. [00:00:37] Five within the lumbar or lower back, five that are fused as the sacrum, and an additional four that are fused together as the coccyx. Within these 33 vertebrae, there are 4 spinal curves. There are two that are a forward flexing or kyphotic curve that we notice in the thoracic and in the sacrum. [00:01:05] The other two curves found in the cervical spine and in the lumbar spine are what we call lordotic or backward bending curves. We describe these spinal curves as either primary or secondary based on how they developed in life. Curves that are kyphotic or forward flexing, such as the thoracic and sacral curves, are considered primary curves because they developed during fetal embryonic development. [00:01:39] The cervical curve then develops in early childhood by six months when the baby starts to hold its head up. And then finally, as the baby or child starts to develop more standing postures, the lumbar curve develops its lordotic curve. This lumbar vertebrae gives us an example to explore the typical characteristics of any vertebrae. [00:02:14] First, the anterior component of a vertebra is its body, which is the large bony structure that gives support to the spinal column. There's also extensive vascular trabecular bone within the body that is covered by cortical bone. The size of these vertebral bodies, both in height and in width, varies throughout the spine. [00:02:40] The vertebral body also has superior and inferior end plates, essentially the top and bottom of the vertebrae that are covered with hyaline cartilage and then connect to the intervertebral discs. Much more on this in the next lecture. The vertebral arch is the combination of the pedicles or the components that come off of the body and the lamina, which close this arch posteriorly. [00:03:11] This arch, combined with the body of the vertebra, creates the vertebral canal which is where the spinal cord passes through. This is also known as the vertebral foramen. So when we talk about the vertebral foramen, we are talking about the large opening within the vertebral body itself. Whereas the intervertebral foramina are the openings that are found on the posterolateral side of a two vertebrae unit, and this is where the spinal nerves pass through. [00:03:46] We can also observe with any vertebra that there are what we call articular facets and articular processes. The articular process is the bony component that extends superiorly and inferiorly to articulate with the articular processes of the superior and inferior vertebrate. The articular facet is the flat hyaline cartilage covered surface on those facets. [00:04:17] We will also notice all vertebrae will have a transverse process or a bony extension that extends laterally. And finally, all vertebrae have a spinous process or a bony extension that extends posteriorly. This slide provides an overview of the structure of the different regions of vertebrae. We will examine these in more detail in the next session. [00:04:47] But mainly cervical vertebrae, we are going to notice the bodies are really the smallest that we see because the neck is a much smaller region. We also will notice some key components such as transverse foramina. Our thoracic vertebrae, we will notice, have a very round vertebral foramina and typically have very long spinous processes. [00:05:12] And finally, our lumbar vertebrae, we notice the largest sized bodies, as well as having some additional processes, such as the mammillary process, that we will talk about when we get into more detail on each region.