Accessory ossicle of the anterior arch of the atlas

The accessory ossicle of the anterior arch of the atlas is a normal variant and is best appreciated on a lateral cervical/sagittal study. It is observed as a circular and corticated osseous density that articulates with the inferior aspect of the anterior arch of the atlas

It is not associated with patient symptomatology. Historical and clinical correlation of injury or other disease states may reveal the other differential considerations as possibilities if radiographic findings are nonspecific. 

Differential diagnosis

Anatomy: Spine
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Article information

rID: 19582
Section: Anatomy
Synonyms or Alternate Spellings:
  • Accessory ossicle at the anterior arch of the atlas

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