Purpose: The term "ponticulus posticus" refers to a partial or complete bony arch over the vertebral artery as it crosses the superolateral surface of the posterior arch of the atlas. This anatomical modification is linked to different symptoms, ranging from neckache to headache and migraine. This bony arch may also be incorrectly assessed during orthopaedic surgery for fixation of C1-C2, with consequent risk of damaging the vertebral artery. Its frequency in the general population has been widely analysed by literature in different geographic contexts, but an analysis of the prevalence of such feature in the Italian population is still missing.
Methods: A Northern Italian orthodontic sample was analysed to assess the prevalence of ponticulus posticus. Lateral teleradiographies of 221 patients were examined. All the patients underwent lateral cephalometry for odontoiatric purposes and none of them was affected by congenital diseases or skeletal deformities.
Results: In the analysed sample, ponticulus posticus had a prevalence of 7.7 % for the complete form, and 9.0 % for the incomplete form. Complete and partial forms were observed, respectively, in 8.8 and 11.0 % of males, and in 6.9 and 7.7 % of females, without statistically significant differences.
Conclusions: The current investigation provided the first data concerning the frequency of ponticulus posticus in Italy: further studies are needed to widen the sample, verify possible regional variations and improve the analysis by more advanced radiological examinations such as CT and cone beam CT scans.
Keywords: Anatomy; Atlas; Ponticulus posticus; Population data.