Atlas vertebra

Atlas Vertebra

The Atlas Vertebra is the most superior (first) cervical vertebra of the spine. It is named for the Atlas of Greek mythology, because it supports the globe of the head.

Anatomy

The Atlas is a ring-like structure consisting of an anterior and a posterior arch and two lateral masses. The Atlas and Axis are specialized to allow a greater range of motion than normal vertebrae. They are responsible for the nodding and rotation movements of the head.

The anterior arch forms about one-fifth of the ring: its anterior surface is convex, and presents at its center the anterior tubercle for the attachment of the Longus colli; posteriorly it is concave, and marked by a smooth, oval or circular facet (fovea dentis), for articulation with the odontoid process (dens) of the axis.

The posterior arch forms about two-fifths of the circumference of the ring: it ends behind in the posterior tubercle, which is the rudiment of a spinous process and gives origin to the Rectus capitis posterior minor and the ligamentum nuchae. The surfaces of the arches are smooth for the attachment of muscles and ligaments.

Clinical significance

Injuries to the Atlas can cause serious consequences, such as vertebral artery injury, spinal cord injury, and even death. The most common types of Atlas fractures are the Jefferson fracture and the Atlas burst fracture.

See also

• Cervical vertebrae
• Axis vertebra
• Vertebral column