Atlas (first cervical vertebra, C1) (Atlas)
Educational content only — not medical advice.
Anatomy
The first cervical vertebra — a ring with no body and no spinous process: anterior and posterior arches join two lateral masses whose superior articular facets receive the occipital condyles in the atlanto-occipital joint for nodding, while the transverse ligament holds the dens of the axis away from the spinal cord.
Clinical notes
A Jefferson fracture (burst of both arches from axial load) usually spares the cord because the fragments disperse; atlantoaxial instability after trauma or inflammation threatens the spinal cord directly.
Related structures
Educational references
FAQ
What is the role of the Atlas (first cervical vertebra, C1)?
The first cervical vertebra — a ring with no body and no spinous process: anterior and posterior arches join two lateral masses whose superior articular facets receive the occipital condyles in the atlanto-occipital joint for nodding, while the transverse ligament holds the dens of the axis away from the spinal cord.
Why is the Atlas (first cervical vertebra, C1) clinically important?
A Jefferson fracture (burst of both arches from axial load) usually spares the cord because the fragments disperse; atlantoaxial instability after trauma or inflammation threatens the spinal cord directly.
Source & license
Derived from Z-Anatomy (Gauthier Kervyn et al.), CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/); upstream geometry from BodyParts3D, © The Database Center for Life Science. license details