Cervical Spine

The cervical spine consists of seven vertebrae that make up the neck region of the spine. These vertebrae are smaller than those in the thoracic and lumbar regions, and their primary function is to support the weight of the head while also providing a great deal of flexibility and movement.

1. C1 – The Atlas: This is the first cervical vertebra, and it’s unique in the fact that it doesn’t have a body or a spinous process, unlike the other vertebrae. Instead, it consists of an anterior and posterior arch and is ring-like in structure. The Atlas is named after the mythological figure who held the world on his shoulders, as the C1 vertebra holds up the skull. It articulates with the occipital bone of the skull above and the Axis (C2) below, permitting nodding of the head.
2. C2 – The Axis: The second cervical vertebra has a characteristic bony prominence known as the odontoid process, or dens, which projects upwards and fits within the ring of the Atlas. This allows for the rotation of the Atlas (and therefore the skull) around the Axis, providing the ability for side-to-side head movement.
3. C3 – C7: The next five vertebrae (C3-C7) are more similar in structure to the rest of the spine’s vertebrae. They all have a body, a vertebral foramen (a hole through which the spinal cord passes), a spinous process that projects outwards at the back, and two transverse processes that project outwards at the sides. Unique to cervical vertebrae are the transverse foramina (holes in the transverse processes), through which the vertebral arteries pass to supply the brain. The spinous processes of C3-C6 are often bifid, or split, but this is variable. The spinous process of C7 is notably longer and is often palpable at the base of the neck, earning it the nickname “vertebra prominens.”

The cervical vertebrae, particularly C1 and C2, have unique structures to support specific movements of the head. The remaining cervical vertebrae allow for flexion, extension, and rotation of the neck, offering great mobility while still protecting the spinal cord and supporting the skull.

Intervertebral discs, made of fibrous cartilage, are present between each pair of vertebrae (from C2-C3 to C7-T1), providing cushioning and shock absorption. These discs can become problematic in conditions like herniated disc disease. The cervical vertebrae are also attached by various ligaments to provide stability to the spine.