🦵 Straight Leg Raise Test Simulator

Supine Positioning for the Straight Leg Raise Test

Patient placement sets the baseline before any nerve tension is applied.

• Supine: Patient position (flat, relaxed)
• 0°: Starting angle (leg fully extended)
• Extended: Knee state (kept straight throughout)
• Lasègue's: Test also known as (sign / maneuver)

Baseline setup

Patient lies supine, legs relaxed and extended on the table.

Beginning the Passive Leg Raise

The examiner lifts the straight leg slowly by the ankle or heel.

• Passive: Raise type (examiner-controlled)
• Ankle/heel: Grip point (knee kept locked)
• Slow: Raise speed (steady controlled lift)
• 0–30°: Early range (usually painless)

Controlled lift

Leg rises slowly while knee stays extended and hip flexes.

Sciatic Nerve Tension Builds With Hip Flexion

Increasing hip flexion stretches the sciatic nerve and its roots.

• Sciatic: Nerve involved (L4–S3 roots)
• ~30°: Tension onset (nerve begins to glide)
• Traction: Mechanism (root stretch over disc)
• High: Sensitivity (for disc herniation)

Root stretch

Nerve root tension rises steadily as the raise angle increases.

Pain Onset Angle Indicates Nerve Root Irritation

Radicular pain typically appears between thirty and seventy degrees.

• 30–70°: Classic window (positive test range)
• Radicular: Pain type (shooting, leg-length pain)
• Unlikely: Below 30° (true nerve pain rare)
• Nonspecific: Above 70° (often hamstring tightness)

Threshold crossing

Pain at the irritated root angle flags a positive finding.

Reproducible leg pain between 30–70° suggests nerve root compression.

Clinical Interpretation of the Straight Leg Raise Angle

The onset angle and pain pattern guide the clinical conclusion.

• 30–70°: Positive test (radicular reproduction)
• >90° ok: Negative test (no pain reproduced)
• High spec.: Crossed SLR (contralateral pain sign)
• Disc herniation: Common cause (L4-L5 / L5-S1)

Putting it together

Angle, pain quality, and severity combine into one classification.