Femoral Nerve Tension Test

Other Names

• Prone Knee Bending Test
• Femoral Nerve Stretch Test
• Mackiewicz sign
• Crossed Femoral Nerve Tension Test (FNST)
• Crossed Femoral Nerve Stretch Test

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Purpose

Femoral Nerve Tension Test

• Evaluate the Femoral Nerve and the mid lumbar (L2-L4) nerve roots

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Description

• The patient lays prone on the examination table
• The examiner stabilizes the ipsilateral pelvis with one hand to prevent movement
• The other hand flexes the knee as much as possible and holds the maximal flexion position for 45 seconds
• Positive test
  • Reproduction of the patients symptoms
• Be sure to compare to unaffected limb

Modifications

• Crossed FNST
  • Patient remains prone
  • Hip extended, knee flexed
  • Passively pull contralateral knee posteriorly, stretching thigh neuromusculature of both sides
  • Positive test is pain in contralateral anterior thigh
    • Due to stretching of the psoas/quads/lumbar disc impinging on femoral nerve roots (L2 L4 distribution)

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Pathology

• Femoral Nerve Injury
• Herniated Nucleus Pulposus

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Evidence

• Unknown

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See Also

• Back Pain (Main)
• Back Anatomy (Main)
• Physical Exam Back

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