Straight leg raise

Overview
The Straight leg raise also, called Lasègue sign or Lasègue test, is a test done during the physical examination to determine whether a patient with low back pain has an underlying herniated disk.

Technique
With the patient lying down on a table, the examiner lifts the patient's leg while the knee is straight.

A variation is to lift the leg while the patient is sitting. However, this reduces the sensitivity of the test.

Interpretation
"The straight leg raise test is positive if pain in the sciatic distribution is reproduced between 30° and 70° passive flexion of the straight leg."

A meta-analysis reported the accuracy is :
 * sensitivity 91%
 * specificity 26%

If the raising the opposite leg causes pain (cross straight leg raising):
 * sensitivity 29%
 * specificity 88%