Ponticles of the atlas: a review and clinical perspective.

The condition of ponticles of the atlas was reviewed in relation to their development, anatomy, incidence and diagnosis with an objective directed toward assessment of their clinical significance. The ponticles are commonly encountered radiographic anomalies characterized by osseous bridging of the posterior margin of the superior articular facet and the posterior arch of the atlas. They are present to a variable degree in about 35% of dissections and a complete osseous ring enclosing the vertebral arteries is identifiable in up to 15% of cases. The ponticles have been considered a significant factor in transient vertebro-basilar insufficiency, Barre-Lieou syndrome and chronic upper cervical syndrome. The presence of atlantic ponticulus should be considered to some degree as a contraindication to forceful manipulation of the cervical spine.