C1 (Atlas) - Transverse Process

C1 - Anterior and Posterior Facets

Position C1 Relative to the Cranial Vault

Atlas Landmarks

The lateral masses of the atlas vertebrae can be visualized on a Dental Orthogonal Xray (mouth open)

Drawing by Elizabeth Cunningham, Reproduced with Permission, 

©Postural Resolution Institute®

Superior facets of the Atlas forming the Occipital Atlas (O/A) Joint.  

The O/A joint is actually comprised of two pairs of facets.  

  • When the chin is tucked, the head sits atop the anterior facets.  
  • When the head is tilted upwards, the posterior facts hold the weight of the head.