Quick Facts
Location: Vertebral column.
Bone Type: Irregular bone.
Key Features: Vertebral body, laminae, pedicles, superior and inferior articular processes, and transverse and spinous processes.
Articulates With: Third and fifth thoracic vertebra, fourth and fifth ribs.
Arterial Supply: Posterior intercostal arteries.
Related parts of the anatomy
Key Features & Anatomical Relations
The fourth thoracic vertebra (vertebra T4) 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 fourth thoracic vertebra is located:
- superior to the fifth thoracic vertebra;
- inferior to the third thoracic vertebra;
- medial to the fourth and fifth ribs.
It articulates with the:
- third and fourth thoracic vertebra at the intervertebral symphyses and zygapophyseal joints;
- fourth and fifth ribs at the costovertebral joint.
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 fourth 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.
Learn more about this topic from other Elsevier products
Vertebra
The spine is a mechanical structure composed of articulating vertebrae connected by zygapophyseal facet joints, intervertebral discs, ligaments, and muscles.
