Fourth Cervical Vertebra

Key Features & Anatomical Relations

The fourth cervical vertebra (vertebra C4) is one of the seven cervical vertebrae of the vertebral column. It is considered a typical cervical vertebra because it has similar characteristic features to those of the third, fifth and sixth cervical vertebrae. The fourth cervical vertebra is classified as an irregular bone, and it 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, anterior and posterior tubercles, uncinate processes, and superior and inferior articular facets.

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

The fourth cervical vertebra is located:

- superior to the fifth cervical vertebra;

- inferior to the third cervical vertebra.

It articulates with the third and fifth cervical vertebrae at the intervertebral symphyses and zygapophyseal joints.

Ossification

Ossification of all typical cervical 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:

- accessory transverse foramina may be present;

- the spinous process may be present in a nonbifid form (Tubbs, Shoja and Loukas, 2016).

Surface Anatomy

The spinous process of the fourth cervical vertebra is difficult to palpate, as it lies deep to the nuchal ligament.

List of Clinical Correlates

- Fracture

- Osteoporosis

- Spinal stenosis

- Scoliosis

- Dislocation

- Spina bifida

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.