Incidence of ponticulus posterior of the atlas in migraine and cervicogenic headache

Background: The clinical significance of the ponticulus posticus is far fro m clear. It has been associated with headaches, Barre-Lieou syndrome, photo phobia, and migraine. However, little epidemiologic evidence for this exist s. Objective: This study investigated the relationship of ponticulus posticus on x-ray studies and headache symptoms in a series of chiropractic patients . Methods: Eight hundred ninety-five patients who visited a chiropractic clin ic for the first time and whose conditions required cervical spine x-ray ex aminations were studied. Complaints were categorized as migraine with aura, migraine without aura, cervicogenic headache, neck pain only, and other co nditions. The presence or absence of the ponticulus posticus (whether parti al or complete) was determined by means of a lateral cervical film and note d as a positive or negative finding. The data were analyzed by frequency an alysis and Pearson's chi(2) test. Results: Forty-six percent of the sample were men and the predominant compl aint was neck pain (33%). Most patients were in the fourth decade of life. The frequencies of the other complaints were migraine with aura (7%), migra ine without aura (4%), cervicogenic headache (22%), other conditions (33%). An 18% prevalence of ponticulus posticus was found. This finding was signi ficantly associated with migraine without aura (chi(2) = 4.97; P = .03) and not with any other conditions. Conclusion: In a chiropractic patient population that required cervical x-r ay examinations, a significant association was found between ponticulus pos ticus and migraine without aura, with an odds ratio of 2.19:1 in favor of t his complaint being present with the osseous anomaly. The mechanism for thi s remains obscure but may be related to ischemic compression of the vertebr al artery or by dural tension at the craniocervical junction.