Neck Bones Anatomy

The neck is a very interesting and unusual part of the body in anatomical terms. It contains vital organs and blood vessels, many of which are not enclosed by a protective bony framework.

The main bones we examine when studying the neck are the vertebrae that form the cervical spine. In this article, we will focus on these bones.

The vertebral column is an extremely important part of the skeleton and forms the main supporting axis of the human body. Its anatomy is closely related to upright posture and the need to support the head and trunk while standing and walking on two legs.

In addition to providing support, the vertebral column protects the spinal cord. Each vertebra has a vertebral foramen formed by the vertebral body and arch.

When the vertebrae are stacked on top of one another, these foramina form the vertebral canal, which contains the spinal cord. The spinal cord carries signals involved in movement and sensation, including touch, pain, and temperature. This is one reason injuries to the vertebral column can be very serious.

The vertebral column is formed by vertebrae separated in most regions by intervertebral discs. These discs contain fibrocartilage and help absorb loads during walking, running, jumping, and other movements. The vertebral column is also stabilized by strong ligaments and muscles.

Rear view of the skull base and upper cervical vertebrae.

The vertebral column is divided into several regions:

Cervical;
Thoracic;
Lumbar;
Sacral;
Coccygeal.

The vertebrae of each region differ in shape and size. Moreover, each region contains a different number of vertebrae.

Typical Cervical Vertebrae

A typical cervical vertebra is small in comparison with the more massive thoracic and lumbar vertebrae.

Typical cervical vertebra shown from above.

If you look at the vertebra, you will immediately see a dense bony mass – this is the vertebral body (corpus vertebrae). The vertebral bodies bear much of the weight transmitted through the spinal column. Intervertebral discs are located between the bodies of adjacent vertebrae.

Behind the vertebral body is the vertebral arch (arcus vertebrae). The vertebral body and arch together enclose the vertebral foramen (foramen vertebrale). When the vertebrae are stacked, these foramina form the vertebral canal containing the spinal cord.

Lateral to the vertebral arch are the transverse processes (processus transversi). The transverse processes of typical cervical vertebrae have several distinctive features, and you can identify a cervical vertebra by characteristics such as:

Small size;
Anterior and posterior tubercles;
The presence of transverse foramina (foramina transversaria).

The cervical vertebrae also have superior and inferior articular processes. Articular processes are present in the other regions of the vertebral column as well.

Cervical vertebra anatomy with the vertebral body, arch, foramina, spinous process, and articular processes labeled.

Atlas

The atlas is the first cervical vertebra. Its anatomy differs significantly from that of the typical cervical vertebrae.

First, the atlas does not have a vertebral body. Instead, it has an anterior arch (arcus anterior) and a posterior arch (arcus posterior), which are connected by the lateral masses and surround the vertebral foramen (foramen vertebrale).

The thickened areas connecting the anterior and posterior arches are called the lateral masses. On their superior and inferior surfaces are articular facets (facies articulares) for articulation with the skull and the second cervical vertebra, respectively.

On the inner surface of the anterior arch of the atlas is a small articular facet called the facet for the dens (fovea dentis).

Atlas vertebra anatomy with the anterior and posterior arches, transverse foramina, articular facets, and facet for the dens labeled.

Axis

The axis is the second cervical vertebra. The atlas and axis form the atlanto-axial joints, which allow much of the rotational movement of the head.

The axis, or second cervical vertebra, has a clearly visible upward projection called the dens. The rounded upper end of this process is called the apex of the dens. The dens articulates with the facet for the dens on the anterior arch of the atlas. This articulation allows the atlas and head to rotate around the dens.

The first two cervical vertebrae differ considerably from the typical cervical vertebrae. Their distinctive anatomical features allow them to support the skull while providing a wide range of head movements.