Dynamic changes in the dimensions of the lumbar spinal canal: an experimental study in vitro

J Orthop Res. 1989;7(1):115-21. doi: 10.1002/jor.1100070116.


The variation in the dimensions of the lumbar spinal canal under both flexion-extension and axial compression-distraction was studied using computerized tomography (CT) scans in human cadaver lumbar spine specimens. In 3-mm-thick CT slices through the disk at L3-L4, the cross-sectional area of the spinal canal was reduced by around 40 mm2, corresponding to a 16% reduction of the initial area when the lumbar spines were moved both from flexion to extension and from distraction to compression. A corresponding reduction in the midsagittal diameter of the canal of 2 mm was found. During these motions, the ligamentum flavum did not appear to be a significant factor for the dynamic changes affecting the dimensions of the canal. This held true even after the disk had been excised in order to produce a total collapse of the disk space.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Humans
  • In Vitro Techniques
  • Intervertebral Disc / diagnostic imaging
  • Lumbosacral Region
  • Movement
  • Spinal Canal / diagnostic imaging*
  • Spinal Canal / physiology
  • Tomography, X-Ray Computed