title: Variations in Entrance of Vertebral Artery in Korean Cervical Spine: MDCT-based Analysis.
abstract: BACKGROUND
  Knowledge of the anatomical variation of the vertebral artery has clinical importance not only for the performance of interventional or surgical procedures itself but also to ensure their safety. We conducted a study of the anatomical variation by reviewing multi-detector computed tomography (MDCT) images of the cervical spine from 460 Korean patients.
  
  
  METHODS
  16-row MDCT data from 460 patients were used in this study. We observed 920 vertebral arteries. Examination points included level of entrance of the artery into the transverse foramen of the cervical vertebra, origin site of the vertebral artery, course of a vertebral artery with aberrant entrance.
  
  
  RESULTS
  The vertebral artery in 2 (0.2%) cases in this study entered into the transverse foramen of the 7th cervical vertebra from the left. In 45 (4.9%) cases, the vertebral artery entered into the transverse foramen of the 5th cervical vertebra. Of these, the entrance was on the right in 15 (1.6%) and on the left in 30 (3.3%). We found 17 (1.8%) cases in which the artery entered into the transverse foramen of the 4th cervical vertebra, 10 (1.1%) on the right and 7 (0.7%) on the left side. As is commonly acknowledged, the 6th cervical vertebra was the most common site of entry; the vertebral artery entered the transverse foramen of the 6th cervical vertebra in the remaining 855 (93.0%) cases, on the right in 434 (47.2%) and on the left in 421 (45.8%).
  
  
  CONCLUSIONS
  In conclusion, the possibility of an atypical course of the vertebral artery in segments V1 and V2 should be evaluated with magnetic resonance imaging (MRI) or CT images before carrying out procedures involving the anterior cervical vertebrae.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Kosin University Gospel Hospital, Busan, Korea.
authors.forename: Hye Young
authors.initials: HY
authors.lastname: Shin
authors.affiliation: Department of Radiology, Pohang Stroke and Spine Hospital, Pohang, Korea.
authors.forename: Ji Kang
authors.initials: JK
authors.lastname: Park
authors.affiliation: Department of Anesthesiology and Pain Medicine, Jeju National University Hospital, Jeju, Korea.
authors.forename: Sun Kyung
authors.initials: SK
authors.lastname: Park
authors.affiliation: Jeju National University School of Medicine, Jeju, Korea.
authors.forename: Gyu Seo
authors.initials: GS
authors.lastname: Jung
authors.affiliation: Department of Anesthesiology and Pain Medicine, Jeju National University Hospital, Jeju, Korea.
authors.forename: Yun Suk
authors.initials: YS
authors.lastname: Choi
keywords: cervical spine; multi-detector computed tomography; vertebral artery