Cervical Vertebrae

Description

The cervical vertebrae are one of the five regional groups of the vertebral column. They are found along the posterior aspect of the neck and are located between the cranium and the thoracic vertebrae. They are numbered one to seven and become progressively larger from superior to inferior. This progressive increase in size is necessary to support the progressive increase in body weight that is placed on each successive vertebra. The cervical vertebrae are unfused and articulate with adjacent vertebrae via:

- intervertebral discs, forming intervertebral symphysis joints;

- articular facets, forming zygapophyseal and atlantoaxial joints.

One of the key characteristic features of the cervical vertebrae is that they all have a foramen transversarium in each of their transverse processes. The cervical vertebrae can be subclassified into typical and atypical groups.

The third to sixth cervical vertebrae are considered typical because they have similar characteristic features:

- vertebral bodies with uncinate processes;

- vertebral foramina that appear triangular when viewed from above;

- spinous processes that are short, horizontally oriented in the posterior direction, and can be bifid or nonbifid, depending on the race and sex of an individual (Duray, Morter and Smith, 1999);

- transverse processes with anterior and posterior tubercles and grooves for spinal nerves;

- superior articular processes with articular facets that face posterosuperiorly;

- inferior articular processes with articular facets that face anteroinferiorly.

The atlas (first cervical vertebra), axis (second cervical vertebra), and seventh cervical vertebra are considered atypical because some of their features differ to those of typical cervical vertebrae:

- the atlas has no vertebral body or spinous process and consists of lateral masses and anterior and posterior arches;

- the axis has a dens;

- the seventh cervical vertebra has a long, nonbifid spinous process.