Emergency Radiology

, Volume 6, Issue 5, pp 290–293

The lateral atlanto-dens interval: normal range of asymmetry

  • L. J. Wolansky
  • V. Rajaraman
  • C. Seo
  • N. Patel
  • K. Kazmi
  • S. Doddakashi
  • S. Siegel
ORIGINAL ARTICLE

DOI: 10.1007/s101400050070

Cite this article as:
Wolansky, L., Rajaraman, V., Seo, C. et al. Emergency Radiology (1999) 6: 290. doi:10.1007/s101400050070

Abstract

Purpose: The object of this study is to determine the normal range of asymmetry of the lateral atlanto-dens interval (LADI). Methods: Ninety-nine consecutive patients who had CT scans of the atlanto-axial complex for reasons unrelated to the upper cervical spine were studied. Subjects with a history of cervical trauma or rheumatoid arthritis were excluded. The LADI was measured at a workstation using an electronic cursor. The difference in the LADI between the right and the left side was taken as the measure of asymmetry. Results: The average asymmetry of the LADI was 0.99 ± 1.05 mm. While a number of subjects had symmetrical LADI, the maximum asymmetry in this study population was 5 mm. Conclusion: Asymmetry of the LADI is not unusual in subjects with no symptoms referable to the upper cervical spine. The LADI as a measurement in itself does not signify any type of clinical pathology. The average asymmetry at the middle third of the dens is approximately 1 mm. Ninety-five percent of patients will have an asymmetry of 3 mm or less. The LADI asymmetry is best determined in a CT section that demonstrates the maximal width of the dens. Radiologists and clinicians should be aware of this normal range of asymmetry when interpreting CT scans of the atlanto-axial region.

Key words Cervical spine – Computerized tomography – Normal anatomy – Odontoid process

Copyright information

© American Society of Emergency Radiology 1999

Authors and Affiliations

  • L. J. Wolansky
    • 1
  • V. Rajaraman
    • 2
  • C. Seo
    • 3
  • N. Patel
    • 3
  • K. Kazmi
    • 3
  • S. Doddakashi
    • 1
  • S. Siegel
    • 1
  1. 1.Department of Radiology, New Jersey Medical School/University of Medicine and Dentistry of New Jersey and Veterans Administration Medical Center, East Orange, New Jersey, USAUS
  2. 2.Division of Neurological Surgery, New Jersey Medical School/University of Medicine and Dentistry of New Jersey, USAUS
  3. 3.New Jersey Medical School/University of Medicine and Dentistry of New Jersey, USAUS
  4. 4.University of Medicine and Dentistry of New Jersey, Department of Radiology/UH C320, 150 Bergen Street, Newark, NJ 07103, USA Tel.: + 1–973–9722323US