Which sign is elicited by extending the knee with the hip flexed, indicating meningeal irritation?

Which sign is elicited by extending the knee with the hip flexed, indicating meningeal irritation?

• A. Kernig's sign
• B. Brudzinski's sign
• C. Nuchal rigidity sign
• D. Babinski sign

Answer: (A)

Kernig's sign demonstrates meningeal irritation. When the hip is flexed to 90 degrees, extending the knee stretches the dura and spinal nerve roots. If the meninges are irritated, this stretch provokes pain and a resistance to full knee extension, sometimes felt as pain in the posterior thigh or lower back. A positive Kernig's sign points toward meningitis or other causes of meningeal irritation. For context, Brudzinski's sign involves involuntary flexion of the hips and knees when the neck is passively flexed, and nuchal rigidity is pure neck stiffness. Babinski sign is an upper motor neuron finding with an extensor plantar response, not a meningeal sign.

Kernig's sign demonstrates meningeal irritation. When the hip is flexed to 90 degrees, extending the knee stretches the dura and spinal nerve roots. If the meninges are irritated, this stretch provokes pain and a resistance to full knee extension, sometimes felt as pain in the posterior thigh or lower back. A positive Kernig's sign points toward meningitis or other causes of meningeal irritation.

For context, Brudzinski's sign involves involuntary flexion of the hips and knees when the neck is passively flexed, and nuchal rigidity is pure neck stiffness. Babinski sign is an upper motor neuron finding with an extensor plantar response, not a meningeal sign.