title: Location of the transverse foramen in the subaxial cervical spine in a young asymptomatic population.
abstract: METHODS
  Computerized tomography of the subaxial cervical spine in 98 young, asymptomatic North American volunteers.
  
  
  OBJECTIVE
  To provide normative data on subaxial transverse foramen dimensions and location in relation to surgical landmarks routinely used during operative intervention in the anterior cervical spine.
  
  
  BACKGROUND
  Vertebral artery injury during anterior cervical spinal surgery is a rare but potentially catastrophic injury. There have been no prior studies in a large group of young, asymptomatic subjects without pathology and where the age, weight, and gender are known. There are no published computerized tomography data evaluating distances between the tip of the uncovertebral joint and the medial margin of the uncovertebral joint, 2 commonly used surgical landmarks.
  
  
  METHODS
  Axial and reconstructed coronal computerized tomography images of cervical vertebrae from C3 to C7 in 98 asymptomatic young volunteers were analyzed to measure interforaminal distance, transverse foramen distance from anterior and posterior vertebral body margins, transverse foramen dimensions, and transverse foramen medial margin distance from the uncus tip and medial margin.
  
  
  RESULTS
  All measurements were significantly different between males and females, with smaller female dimensions. Interforaminal distance gradually increased from C3 to C7. Transverse foramen anterior margin in relation to the anterior vertebral body was significantly more posterior at C7 compared with the C3-C6 levels. Transverse foramen posterior margin in relation to the vertebral body posterior margin gradually moved anteriorly from C3 to C6 and then posterior again at C7. The vertebral uncus tip and medial margin in relation to the medial transverse foramen averaged 2.8 mm and 5.7 mm for males and 2.7 mm and 5.3 mm for females from C3 to C6. CONCLUSION.: Useful morphometric data are provided that may assist the operating surgeon to avoid vertebral artery injury during anterior surgical approaches to the cervical spine. The medial margin of the uncovertebral joint may be the safest landmark to avoid vertebral artery injury during anterior cervical disc surgery. The vertebral artery is at increased risk of injury during neural decompression at more cephalad levels.
authors.affiliation: Department of Orthopaedic Surgery, Medical College of Wisconsin, Milwaukee, WI, USA.
authors.forename: Steven W
authors.initials: SW
authors.lastname: Malik
authors.forename: Brian D
authors.initials: BD
authors.lastname: Stemper
authors.forename: Umesh
authors.initials: U
authors.lastname: Metkar
authors.forename: Narayan
authors.initials: N
authors.lastname: Yoganandan
authors.forename: Barry S
authors.initials: BS
authors.lastname: Shender
authors.forename: Raj D
authors.initials: RD
authors.lastname: Rao
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001368:Axis, Cervical Vertebra / Q000000981:diagnostic imaging*; D001270:Cervical Atlas / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D019637:Orthopedic Procedures / Q000009:adverse effects; D012737:Sex Factors; D014057:Tomography, X-Ray Computed; D014711:Vertebral Artery / Q000000981:diagnostic imaging*; D055815:Young Adult