What is Kernig sign?

What is Kernig sign?

• A. Leg extension on a 90-degree flexed hip causes pain
• B. Neck stiffness with leg raise
• C. Foot drop
• D. Pain with hip flexion

Answer: (A)

Kernig sign points to meningeal irritation, such as from meningitis or a subarachnoid hemorrhage. To test it, have the patient lie flat, flex the hip to 90 degrees, and then extend the knee. If extending the knee provokes pain or a painful resistance, it’s a positive sign. This is described as leg extension with a 90-degree flexed hip causing pain. That differentiates it from other signs: neck stiffness with leg raise is Brudzinski sign, not Kernig. Pain with hip flexion suggests different hip or psoas involvement, not meningeal irritation. Foot drop is unrelated to meningeal signs.

Kernig sign points to meningeal irritation, such as from meningitis or a subarachnoid hemorrhage. To test it, have the patient lie flat, flex the hip to 90 degrees, and then extend the knee. If extending the knee provokes pain or a painful resistance, it’s a positive sign. This is described as leg extension with a 90-degree flexed hip causing pain.

That differentiates it from other signs: neck stiffness with leg raise is Brudzinski sign, not Kernig. Pain with hip flexion suggests different hip or psoas involvement, not meningeal irritation. Foot drop is unrelated to meningeal signs.