Well, hello again! It’s Matt from Kenhub, and in this tutorial, we will be discussing the thoracic spine. The thoracic vertebrae – seen here on this image highlighted in green from a dorsal view – are located in the middle section of the vertebral column specifically inferior to the cervical vertebrae and superior to the lumbar vertebrae. These vertebrae span a large majority of the chest cavity area. The vertebrae are separated by intervertebral discs of fibrocartilage which are flexible cartilage discs located between the bodies of two adjacent vertebrae that allow movement in the spine and have a shock absorbing or cushioning function as well. In addition to providing shock resistance and cushioning, the discs also help bind adjacent vertebrae together.
There are twelve thoracic vertebrae denoted as T1 to T12 found in adult humans and they are situated in between the cervical and lumbar vertebrae with a general sizing larger than the cervical but smaller than the lumbar vertebrae. For each of the twelve thoracic vertebrae, there is a corresponding pair of ribs attached to them. This is unique since no other vertebrae have ribs attached to them. Thoracic vertebrae increase in size as they descend towards the lumbar vertebrae. This is because the lower vertebrae must be able to support more of the body's weight when a person is standing due to the effects of gravity.
Distinguishing features of the thoracic vertebrae include the presence of facets on the sides of the bodies for articulation with the heads of the ribs and facets on the transverse processes of all except the eleventh and twelfth vertebrae for articulation with the tubercles of the ribs.
The superior costal facet – seen here highlighted in green on this image of the lateral view of the vertebra – is a fossa where the head of the rib articulates. The inferior costal facet also articulates with the head of a rib; however, it is located on the lower edge of the body of the vertebra. The costal facet of the transverse process of the vertebra is the facet for articulation of the vertebra with the tubercle of the rib. In addition, the spinous processes are relatively more pointed than other vertebrae and angled sharply downward. The body of a thoracic vertebra seen here highlighted in green is somewhat heart-shaped.
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