Dens

Dens is a term in anatomy that refers to a part of the second cervical vertebra, or axis, which is named for its tooth-like projection that fits into the vertebra above it. This structure allows for the rotation of the head.

Anatomy

The dens, also known as the odontoid process, is a strong, tooth-like process projecting upwards from the body of the axis. It serves as a pivot that allows the first cervical vertebra, known as the atlas, to rotate around it.

The dens is held in place by the transverse ligament of the atlas, which wraps around the dens and holds it against the anterior arch of the atlas. This allows for rotation of the atlas and the head, while also keeping the dens and atlas in alignment.

Clinical significance

Due to its pivotal role in the rotation of the head, the dens is susceptible to fractures. A fracture of the dens is a serious condition that can lead to instability of the cervical spine and potential damage to the spinal cord.

Rheumatoid arthritis can also affect the dens, leading to its erosion and subsequent instability of the cervical spine. This can result in a condition known as atlantoaxial instability, which can cause severe neck pain and neurological symptoms.

See also

• Axis
• Atlas
• Cervical vertebrae
• Rheumatoid arthritis
• Atlantoaxial instability

References

Dens Resources
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