title: Anatomical variations of the foramen transversarium in cervical vertebrae: findings, review of the literature, and clinical significance during cervical spine surgery.
abstract: To describe certain anatomical variations of the foramen transversarium, in spine cervical vertebrae in a contemporary specimen of an Indo-European population and approach their clinical importance during cervical spine surgery.
  
  
  
  102 cervical vertebrae (C2-C7) from 17 different skeletons, intact without any degenerative or traumatic disorders, which belonged to the collection of the Department of Anatomy, were examined. The age of specimens at the time of their death was between 25 and 65 years. All foramina were measured with a digital caliper.
  
  
  
  The average size of the normal foramina was: 6.49 mm × 5.74 mm on the right side and 6.65 mm × 5.76 mm on the left side. Regarding the variations, we found two cervical vertebrae (1.96 %), one C3and one C6, in which the right foramen transversarium is clearly smaller than the left. The exact dimensions of these foramina are: 2.3 mm × 2.5 mm on the right side and 6.54 mm × 8 mm on the left side in the first vertebra and 2.8 mm × 3.74 mm on the right side and 6 mm × 7.5 mm on the left side, in the second one. We also observed double foramina in 14 vertebrae (13.72 %). In seven vertebrae, the duplication was bilateral (6.86 %). We finally found one vertebra (0.98 %) with triplication of the foramen transversarium on the left side.
  
  
  
  Summarizing, 10 out of our 17 skeletons were presented with variations (extremely narrow or multiple foramina). This finding of hypoplastic, duplicated and triplicated foramina transversaria in unexpectedly high rates raises questions about the integrity of the contained structures, the possibility of a different path for them. These variations may induce an extra-osseous position of the vertebra artery, and the ignorance of such an event may have catastrophic consequences during a surgery in the cervical spine.
authors.affiliation: Department of Anatomy, School of Health Sciences, University of Thessaly, Panepistimion 3st Biopolis, 41110, Larissa, Greece. ahzibis@med.uth.gr.
authors.forename: Aristeidis H
authors.initials: AH
authors.lastname: Zibis
authors.affiliation: Department of Anatomy, School of Health Sciences, University of Thessaly, Panepistimion 3st Biopolis, 41110, Larissa, Greece.
authors.forename: Vasileios
authors.initials: V
authors.lastname: Mitrousias
authors.affiliation: Department of Anatomy, School of Health Sciences, University of Thessaly, Panepistimion 3st Biopolis, 41110, Larissa, Greece.
authors.forename: Kyriaki
authors.initials: K
authors.lastname: Baxevanidou
authors.affiliation: Department of Orthopaedics, School of Health Sciences, University of Thessaly, 41110, Larissa, Greece.
authors.forename: Michael
authors.initials: M
authors.lastname: Hantes
authors.affiliation: Department of Orthopaedics, School of Health Sciences, University of Thessaly, 41110, Larissa, Greece.
authors.forename: Theofilos
authors.initials: T
authors.lastname: Karachalios
authors.affiliation: Department of Anatomy, School of Health Sciences, University of Thessaly, Panepistimion 3st Biopolis, 41110, Larissa, Greece.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Arvanitis
mesh_terms: D000328:Adult; D000368:Aged; D063405:Anatomic Variation; D002574:Cervical Vertebrae / Q000033:anatomy & histology* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012727:Sex Characteristics; D014711:Vertebral Artery / Q000033:anatomy & histology
keywords: Cervical vertebrae; Double foramen transversarium; Hypoplastic foramen transversarium; Spine anatomical variations; Triple foramen transversarium