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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