How is sciatic nerve tension evaluated in patients with mechanical low back pain?

Updated: Mar 30, 2020
  • Author: Everett C Hills, MD, MS; Chief Editor: Stephen Kishner, MD, MHA  more...
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Clinical tests for signs of sciatic nerve tension are as follows:

  • Supine straight leg raising (SLR) test - Reproduction of pain caused by elevation of the contralateral limb raises the probability of a disk herniation to 98%. Remember that the SLR test result can be negative in persons with spinal stenosis.

  • Sitting SLR (knee extension) test (for lower roots) - The patient should sit on the table edge with both hips and knees flexed at 90° and extend the knee slowly. This maneuver stretches the nerve roots as much as a moderate degree of supine SLR. The SLR test result, if positive, reproduces symptoms of sciatica with pain that radiates below the knee.

  • The prone SLR test (also called the reverse SLR test or the femoral nerve stretch test) assesses the upper lumbar roots, a less common site of radiculopathy worth remembering.

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