anatomyEXPERT - Thoracic vertebrae

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Thoracic vertebrae

Other Terms: Thoracic vertebrae, Thoracic vertebrae (TI-TXII), Thoracic vertebrae [T I - T XII], Thoracic vertebrae set, Vertebrae thoracicae (TI-TXII), Vertebrae thoracicae [T I - T XII]

Type

group

Description

The thoracic vertebrae, of which there are twelve, are the most numerous type of vertebrae. They get progressively larger from cranial to caudal in the vertebral column. They are easily identified by the costal facets formed on their bodies and transverse processes. Because of their association with the ribs they are the least mobile of the vertebrae. The laminae and spines of these vertebrae project caudally to overlap with the subjacent vertebra. This suite of characteristics produces a strong imbricated column of bone forming the impressive thoracic skeletal cage.

Etymology

Thorax arises from the Greek word thorakos meaning a breast-plate or cuirass. Since this vestment covered the upper portion of the trunk, this bodily region adapted its name from this covering. The word vertebrae is the plural form of vertebra. It arises from the Latin verb vertere meaning to turn. In 30 A.D., Celsus originally used the word to describe a joint as well as a bone of the spine. It was during the Renaissance revival of anatomy that the term attained its present meaning as a reference to the back bones.

Articulations

The thoracic vertebrae articulate with each superjacent and subjacent thoracic vertebra, the last cervical vertebra, and the first lumbar vertebra. The two superior articular facets articulate with the corresponding inferior articular facets of the adjacent vertebra and the superior and inferior surfaces of the vertebral bodies form an articulation via the intervertebral disc of cartilage. The thoracic vertebrae also articulate with the twelve ribs. They form two articulations with the ribs. The head of the rib articulates with the body of the vertebra and the costal tubercle articulates with the transverse process.

Ossification

Five cartilaginous centers arise as anlage to all vertebrae and ribs. One center forms the body, two anterolateral centers form the costal elements, two posterolateral centers form the vertebral arch elements.