What is the angle range associated with a positive straight leg raise for disc herniation?

What is the angle range associated with a positive straight leg raise for disc herniation?

• A. 20-30 degrees
• B. 60-100 degrees
• C. 40-70 degrees
• D. 0-20 degrees

Answer: (C)

The straight leg raise measures how much neural tissue tension is needed to provoke radicular symptoms from the lumbar nerve roots. When a disc herniation irritates a nerve root, lifting the leg with the knee straight stretches that nerve root and often reproduces radiating pain in the leg. The common window where this pain is most reliably elicited is about 40 to 70 degrees of hip flexion. Angles lower than 40 degrees may not tension the nerve enough and can be influenced by hamstring tightness, while angles much higher than 70 degrees reduce the specificity for nerve root irritation. So, a positive result within roughly 40–70 degrees best indicates disc-related radiculopathy.

The straight leg raise measures how much neural tissue tension is needed to provoke radicular symptoms from the lumbar nerve roots. When a disc herniation irritates a nerve root, lifting the leg with the knee straight stretches that nerve root and often reproduces radiating pain in the leg. The common window where this pain is most reliably elicited is about 40 to 70 degrees of hip flexion. Angles lower than 40 degrees may not tension the nerve enough and can be influenced by hamstring tightness, while angles much higher than 70 degrees reduce the specificity for nerve root irritation. So, a positive result within roughly 40–70 degrees best indicates disc-related radiculopathy.