Ponticulus posticus on the Posterior Arch of Atlas, Prevalence Analysis in Asymptomatic Patients

The Ponticulus posticus is a bony bridge located in the posterior arch of the atlas in relation to the passage of the vertebral artery. Its presence has been associated with development of cervical pain and cerebrovascular disorders. The purpose of this study was to assess its prevalence in asymptomatic patients. We examined 436 digital teleradiographs of patients aged from 5 to 70 years (mean of 18.44 years, SD. 9.59) of both sexes (173 men, 263 women). In 80.7% (n = 352) of cases, no radiographic evidence of ossification was found; 19.3% showed some degree of ossification, of which 10.1% had partial ossification and 9.2% complete ossification. The prevalence of complete ossification was slightly higher in women than in men and occurs in all the age groups analyzed. Our results suggest that the Ponticulus posticus is an anatomic condition with a protective function.