What is the proper technique for performing a straight leg raising (SLR) test?

Proper Technique for Performing the Straight Leg Raising Test

The straight leg raising (SLR) test should be performed with the patient lying supine, raising one leg at a time with the knee extended, until pain is reproduced or limitation is encountered, which serves as a sensitive screening tool for lumbar disc herniation and nerve root compression. 1

Standard SLR Technique

Patient Positioning

• Position the patient supine on a firm examination table
• Ensure the patient is relaxed with legs straight and feet uncrossed
• The spine should be in a neutral position with arms at the sides

Execution Steps

1. Stand beside the leg to be tested
2. Place one hand under the patient's heel and the other hand just above the knee to keep it extended
3. Slowly raise the straightened leg by flexing at the hip while maintaining knee extension
4. Continue raising until the patient reports pain or discomfort
5. Note the angle of hip flexion when pain is first reported (measured from the horizontal)
6. Document the location and character of pain (radicular pain along the sciatic nerve distribution is considered a positive test)

Interpretation

• A positive test reproduces the patient's radicular symptoms (pain radiating down the leg)
• Hip flexion angle less than 60° is generally considered a strongly positive test
• Normal range is typically 80-90° of hip flexion without pain

Enhanced SLR Techniques

Structural Differentiation

To confirm neural involvement and improve diagnostic accuracy, add these maneuvers after pain is provoked 2:

• Ankle Dorsiflexion: Once pain is elicited at a specific angle, dorsiflex the ankle while maintaining the leg position

  • Increased pain with dorsiflexion suggests neural tension/involvement

• Hip Internal Rotation: Apply gentle internal rotation of the hip at the angle where pain is first reported

  • Increased symptoms indicate neural tissue involvement rather than hamstring tightness

Seated SLR Variation

• While the seated SLR is an alternative method, research shows it is less sensitive (0.41) compared to the supine SLR (0.67) 3
• Consider using the seated version only as a complementary test or when supine positioning is not possible

Common Pitfalls and Considerations

• Avoid excessive force: Apply gentle, steady pressure when raising the leg
• Watch for hip rotation: Maintain neutral rotation of the hip during the test
• Beware of hamstring tightness: Differentiate between hamstring tightness (posterior thigh pain) and true radicular symptoms
• Consider bilateral testing: Always test both legs for comparison, even if symptoms are unilateral
• Document properly: Record the angle of elevation, location of pain, and any additional maneuvers performed

Clinical Significance

• The SLR test has high sensitivity (0.84) but moderate specificity (0.52) for lumbar disc herniation 1
• Consider combining with other neurological tests (reflexes, strength, sensation) for a more comprehensive assessment
• A negative SLR does not completely rule out disc pathology; consider the Slump test which has higher sensitivity in cases where SLR is negative 1

Special Applications

For monitoring neurological recovery after neuraxial anesthesia, the SLR can be used as a screening tool:

• The patient should be able to straight-leg raise (raise the heel off the bed against gravity) by 4 hours after the last dose of epidural/spinal local anesthetic 4
• Inability to perform this movement at 4 hours post-anesthesia warrants clinical assessment by an anesthetist 4