title: Prevalence of ponticulus posticus in a Northern Italian orthodontic population: a lateral cephalometric study.
abstract: OBJECTIVE
  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.
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, V. Mangiagalli 31, Milan, Italy. daniele.gibelli@unimi.it.
authors.forename: Daniele
authors.initials: D
authors.lastname: Gibelli
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, V. Mangiagalli 31, Milan, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Cappella
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, V. Mangiagalli 31, Milan, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Cerutti
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, V. Mangiagalli 31, Milan, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Spagnoli
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, V. Mangiagalli 31, Milan, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Dolci
authors.affiliation: Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, V. Mangiagalli 31, Milan, Italy.
authors.forename: Chiarella
authors.initials: C
authors.lastname: Sforza
mesh_terms: D000293:Adolescent; D063405:Anatomic Variation; D002508:Cephalometry; D001270:Cervical Atlas / Q000002:abnormalities* / Q000000981:diagnostic imaging; D002648:Child; D005260:Female; D006801:Humans; D008297:Male
keywords: Anatomy; Atlas; Ponticulus posticus; Population data