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Thoracic vertebrae

The thoracic vertebrae (Latin: vertebrae thoracicae) are twelve vertebrae (T1 - T12) forming the middle or the thoracic part of the spine. These vertebrae are characterized by their articulation with the ribs. The thoracic vertebrae participate in forming the rib cage.

Spine, Thoracic spine, Cervical spine, Lumbar spine, Sacrum, Coccyx, Anterior view
Thoracic spine (without intervertebral discs) by Anatomy.app
Spine, Thoracic spine, Cervical spine, Lumbar spine, Sacrum, Coccyx, Anterior view
Thoracic spine (with intervertebral discs) by Anatomy.app

The typical characteristic features of the thoracic vertebrae are the costal or rib facets on their vertebral bodies and transverse processes. Like cervical vertebrae, thoracic vertebrae are also subdivided into typical and atypical vertebrae depending on the presence and shape of the costal facets.

Within the thorax, the thoracic vertebrae form several joints. The vertebral bodies of the thoracic vertebrae articulate with the ribs forming the costovertebral joints, while the articulations between the ribs and transverse processes of the thoracic vertebrae form the costotransverse joints.

 

Typical thoracic vertebrae

The typical thoracic vertebrae are considered to be the second through ninth thoracic vertebrae (T2 - T9). These vertebrae present the following landmarks:

  • Vertebral body
  • Superior and inferior costal demi-facets (2)
  • Lamina (2)
  • Pedicle (2)
  • Vertebral foramen
  • Intervertebral foramen (2)
  • Transverse process (2)
  • Transverse costal facet (2)
  • Spinous process
  • Superior articular process (2)
  • Inferior articular process (2)
Spine, Thoracic vertebra, Typical thoracic vertebra, Fifth thoracic vertebra, T5, Landmarks, Costal facets, Superior view
Landmarks of typical thoracic vertebra (T5; superior view) by Anatomy.app

The vertebral body of a typical thoracic vertebra appears heart-shaped when viewed from above, and it is usually as broad in the anteroposterior as in the transverse direction. The vertebral body on either side presents two partial facets - superior and inferior costal demi-facets - for articulation with the head of its corresponding rib and the rib below.

The laminae are broad and thick. They overlap the laminae of a subjacent vertebra like tiles of a roof and connect with pedicles to surround and provide protection to the spinal cord. The pedicles of the thoracic vertebrae are directed backward and slightly upward.

Spine, Thoracic vertebra, Typical thoracic vertebra, Fifth thoracic vertebra, T5, Landmarks, Costal facets, Lateral view
Landmarks of typical thoracic vertebra (T5; lateral view) by Anatomy.app

The typical thoracic vertebra has a circular vertebral foramen - a large opening located posterior to the body forming the spinal canal. The intervertebral foramen are two small and circular openings on either side of the vertebra in each intervertebral level.

The transverse processes of each thoracic vertebrae present a transverse costal facet that articulates with the tubercle of its corresponding rib. The spinous process appears long and triangular-shaped in coronal cross-section studies. It projects obliquely downward, arising from the laminae.

Spine, Thoracic vertebra, Typical thoracic vertebra, Fifth thoracic vertebra, T5, Landmarks, Costal facets, Inferior view
Landmarks of typical thoracic vertebra (T5; inferior view) by Anatomy.app

The superior articular processes are two thin bony plates projecting upward from the junctions of the pedicles and laminae. The inferior articular processes are two projections going downward from the vertebral bodies also from the junction sites of pedicles and laminae.

 

Atypical thoracic vertebrae

The atypical thoracic vertebrae include the first, tenth, eleventh and twelfth vertebrae. These vertebrae present the same anatomical landmarks as typical vertebrae, but the shape and presence of costal facets differ.

  • The first thoracic vertebra (T1) contains a whole superior costal facet and an inferior costal demi-facet. It also has a transverse costal facet.
Spine, Thoracic vertebra, Atypical thoracic vertebra, First thoracic vertebra, T1, Landmarks, Costal facets, Lateral view
Landmarks of first thoracic vertebra (T1; lateral view) by Anatomy.app
  • The tenth thoracic vertebra (T10) presents a superior costal demi-facet and lacks an inferior costal demi-facet. It contains a transverse costal facet.
Spine, Thoracic vertebra, Atypical thoracic vertebra, Tenth thoracic vertebra, T10, Landmarks, Costal facets, Lateral view
Landmarks of tenth thoracic vertebra (T10; lateral view) by Anatomy.app
  • The eleventh and twelfth thoracic vertebrae (T11 and T12) have whole costal facets on their vertebral bodies but lack transverse costal facets.
Spine, Thoracic vertebra, Atypical thoracic vertebra, Eleventh thoracic vertebra, T11, Landmarks, Costal facets, Lateral view
Landmarks of eleventh thoracic vertebra (T11; lateral view) by Anatomy.app
Spine, Thoracic vertebra, Atypical thoracic vertebra, Twelfth thoracic vertebra, T12, Landmarks, Costal facets, Lateral view
Landmarks of twelfth thoracic vertebra (T12; lateral view) by Anatomy.app