Cervical vertebrae
Overview
The cervical vertebrae are the seven vertebrae of the vertebral column located in the neck region, immediately below the skull. These vertebrae are designated C1 through C7, with C1 being closest to the skull and C7 closest to the thoracic vertebrae. The cervical vertebrae are unique in their structure and function, providing support and mobility to the head and neck while protecting the spinal cord.
Anatomy
General Structure
The cervical vertebrae are characterized by their small size and the presence of a foramen in each transverse process, known as the transverse foramen. This foramen allows the passage of the vertebral artery, vein, and sympathetic nerves. The vertebral bodies of the cervical vertebrae are smaller compared to those of the thoracic and lumbar vertebrae, reflecting the lesser weight-bearing role of the cervical spine.
Individual Vertebrae
C1 (Atlas)
The atlas is the first cervical vertebra (C1) and is unique in its structure. It lacks a vertebral body and a spinous process. Instead, it consists of an anterior and a posterior arch, connected by lateral masses. The atlas supports the skull and forms the atlanto-occipital joint with the occipital condyles of the skull, allowing for nodding movements of the head.
C2 (Axis)
The axis is the second cervical vertebra (C2) and is distinguished by the presence of the odontoid process, or dens, which projects upward from the vertebral body. The dens acts as a pivot for the rotation of the atlas and the skull, forming the atlanto-axial joint. This joint allows for rotational movements of the head.
C3-C6
The third through sixth cervical vertebrae (C3-C6) share common features, including a small vertebral body, a large and triangular vertebral foramen, and bifid spinous processes. The transverse processes contain transverse foramina for the passage of the vertebral arteries.
C7 (Vertebra Prominens)
The seventh cervical vertebra (C7) is known as the vertebra prominens due to its prominent spinous process, which is easily palpable at the base of the neck. C7 has a larger vertebral body compared to the other cervical vertebrae and a single, non-bifid spinous process.
Function
The cervical vertebrae play a crucial role in supporting the head, protecting the spinal cord, and allowing a wide range of head and neck movements. The unique structure of the atlas and axis enables significant rotational and nodding movements, while the other cervical vertebrae contribute to flexion, extension, lateral flexion, and rotation.
Clinical Significance
Common Conditions
Cervical Spondylosis
Cervical spondylosis is a degenerative condition affecting the cervical spine, often associated with aging. It involves the wear and tear of the intervertebral discs, vertebral bodies, and facet joints, leading to pain, stiffness, and reduced mobility.
Herniated Disc
A herniated disc in the cervical spine occurs when the nucleus pulposus of an intervertebral disc protrudes through a tear in the annulus fibrosus. This can compress nearby nerve roots, causing pain, numbness, and weakness in the neck, shoulders, and arms.
Cervical Radiculopathy
Cervical radiculopathy is a condition resulting from the compression or irritation of a cervical nerve root. It can cause radiating pain, numbness, and weakness in the areas served by the affected nerve.
Diagnostic Imaging
Diagnostic imaging techniques such as X-rays, MRI, and CT scans are commonly used to evaluate the cervical vertebrae and diagnose various conditions. These imaging modalities provide detailed views of the vertebral bodies, intervertebral discs, and surrounding soft tissues.