The Straight leg raise, also called Lasègue

Charles Lasègue

Charles Lasègue, full name Ernest-Charles Lasègue was a French physician who was born in Paris. In 1847 he received his medical doctorate from the University of Paris, and during the following year was sent to Southern Russia by the French government to research an epidemic of cholera...

's sign, Lasègue test or Lazarević's sign, is a test done during the physical examination to determine whether a patient with low back pain

Low back pain

Low back pain or lumbago is a common musculoskeletal disorder affecting 80% of people at some point in their lives. In the United States it is the most common cause of job-related disability, a leading contributor to missed work, and the second most common neurological ailment — only headache is...

 has an underlying herniated disk

Spinal disc herniation

A spinal disc herniation , informally and misleadingly called a "slipped disc", is a medical condition affecting the spine due to trauma, lifting injuries, or idiopathic, in which a tear in the outer, fibrous ring of an intervertebral disc allows the soft, central portion A spinal disc herniation...

, mostly located at L5 (fifth lumbar

Lumbar

In tetrapod anatomy, lumbar is an adjective that means of or pertaining to the abdominal segment of the torso, between the diaphragm and the sacrum ...

 spinal nerve), S1 (the first sacral spinal nerve) or S2 (the second sacral spinal nerve).

Technique

With the patient lying down on his/her back on an examination table/or exam floor, 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 degrees passive flexion of the straight leg."

A meta-analysis

Meta-analysis

In statistics, a meta-analysis combines the results of several studies that address a set of related research hypotheses. In its simplest form, this is normally by identification of a common measure of effect size, for which a weighted average might be the output of a meta-analyses. Here the...

 reported the accuracy as:

• sensitivity 91%
• specificity 26%

If raising the opposite leg causes pain (cross straight leg raising):

• sensitivity 29%
• specificity 88%

Lasègue's sign

Lasègue's sign was named after Charles Lasègue

Charles Lasègue

Charles Lasègue, full name Ernest-Charles Lasègue was a French physician who was born in Paris. In 1847 he received his medical doctorate from the University of Paris, and during the following year was sent to Southern Russia by the French government to research an epidemic of cholera...

 (1816-1883). In 1864, Lasègue described the signs of developing low back pain while straightening the knee when the leg has already been lifted. In 1880, Serbian doctor Laza Lazarević

Laza Lazarevic

Laza K. Lazarević was a Serbian writer, psychiatrist, and neurologist. The primary interest of Lazarević throughout his short life was the science of medicine...

described the straight leg raise test as it is used today, so the sign is often named Lazarević's sign in Serbia and some other countries.