Which finding best indicates a positive straight leg raise for nerve root tension?

Which finding best indicates a positive straight leg raise for nerve root tension?

• A. Pain confined to the hamstring
• B. Pain-free movement
• C. Dermatomal radicular pain between 30 and 70 degrees
• D. Pain only with ankle dorsiflexion

Answer: (C)

The key idea is that the straight leg raise tests nerve root tension by stretching the sciatic nerve and its roots as the leg is lifted. A truly positive finding is when the patient experiences radicular pain that travels down the leg in a clear dermatomal pattern, and this pain is reproduced when the leg is raised within about 30 to 70 degrees of hip flexion. This specific angle range reflects the amount of nerve elongation that commonly irritates the L5–S1 nerve roots; seeing dermatomal pain in that distribution confirms nerve involvement rather than a muscle issue. If the pain is confined to the hamstring, it points to hamstring tightness rather than nerve root tension. Pain-free movement indicates no nerve irritation, and pain that appears only with ankle dorsiflexion suggests an added tension sign (like Bragard) but is not the classic, most specific indicator of a positive straight leg raise for nerve root tension.

The key idea is that the straight leg raise tests nerve root tension by stretching the sciatic nerve and its roots as the leg is lifted. A truly positive finding is when the patient experiences radicular pain that travels down the leg in a clear dermatomal pattern, and this pain is reproduced when the leg is raised within about 30 to 70 degrees of hip flexion. This specific angle range reflects the amount of nerve elongation that commonly irritates the L5–S1 nerve roots; seeing dermatomal pain in that distribution confirms nerve involvement rather than a muscle issue.

If the pain is confined to the hamstring, it points to hamstring tightness rather than nerve root tension. Pain-free movement indicates no nerve irritation, and pain that appears only with ankle dorsiflexion suggests an added tension sign (like Bragard) but is not the classic, most specific indicator of a positive straight leg raise for nerve root tension.