Sixth Thoracic Vertebra

Key Features & Anatomical Relations

The sixth thoracic vertebra (vertebra T6) is one of the twelve thoracic vertebrae of the vertebral column. It is classified as an irregular bone and includes the following bony features:

- parts: vertebral body, laminae, pedicles, superior and inferior articular processes, and transverse and spinous processes;

- surfaces: superior and inferior intervertebral surfaces, superior and inferior annular epiphyses, and vertebral arch;

- landmarks: superior and inferior vertebral notches, superior and inferior articular facets, and superior, inferior, and transverse costal facets.

More information regarding these and other bony features can be found in the Parts, Surfaces, and Landmarks tabs for this bone.

The sixth thoracic vertebra is located:

- superior to the seventh thoracic vertebra;

- inferior to the fifth thoracic vertebra;

- medial to the sixth and seventh ribs.

It articulates with the:

- fifth and seventh thoracic vertebrae at the intervertebral symphyses and zygapophyseal joints;

- sixth and seventh ribs at the costovertebral joints.

Ossification

Ossification of all thoracic vertebrae occurs at eight ossification centers, these are found in the:

- vertebral body, which appears in utero during the second to fourth months;

- right and left halves of the vertebral arch, with one center found in each, which appear in utero during the third month;

- right and left transverse processes, with one center found in each, which appear during puberty;

- spinous process, which appears during puberty;

- superior and inferior annular epiphyses, with one center found in each, which appear during puberty.

The ossification centers for the right and left halves of the vertebral arch fuse with each other during the first year after birth. The vertebral arch fuses with the vertebral body during the third year. The remaining centers fuse with the vertebral arch and body during early adulthood (Standring, 2016).

Variations

In some individuals:

- the pedicles of thoracic vertebrae can display significant morphological variation;

- the transverse processes may fail to ossify (Tubbs, Shoja and Loukas, 2016).

Surface Anatomy

The spinous process of the sixth thoracic vertebra can be palpated, especially during flexion of the neck and trunk.

List of Clinical Correlates

- Fracture

- Osteoporosis

- Spinal stenosis

- Scoliosis

- Spondylosis

- Spondylolisthesis

- Spondylolysis

- Butterfly vertebra

References

Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Gray's Anatomy Series 41st edn.: Elsevier Limited.

Tubbs, R. S., Shoja, M. M. and Loukas, M. (2016) Bergman's Comprehensive Encyclopedia of Human Anatomic Variation. Wiley.