Which sign is described by hip and knee flexion when the neck is flexed?

Which sign is described by hip and knee flexion when the neck is flexed?

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

Answer: (C)

When the meninges are irritated, bending the neck can trigger a reflex that pulls the legs up. If passive neck flexion causes the hips and knees to flex, that is Brudzinski's sign, a classic indicator of meningeal irritation such as meningitis. This sign is different from nuchal rigidity, which is just neck stiffness without the leg movement, and from Kernig's sign, where you flex the hip and knee to 90 degrees and then try to straighten the knee to see if pain or resistance occurs. Babinski's sign is a separate motor/upper motor neuron finding. So the described response—hip and knee flexion when the neck is flexed—maps to Brudzinski's sign.

When the meninges are irritated, bending the neck can trigger a reflex that pulls the legs up. If passive neck flexion causes the hips and knees to flex, that is Brudzinski's sign, a classic indicator of meningeal irritation such as meningitis. This sign is different from nuchal rigidity, which is just neck stiffness without the leg movement, and from Kernig's sign, where you flex the hip and knee to 90 degrees and then try to straighten the knee to see if pain or resistance occurs. Babinski's sign is a separate motor/upper motor neuron finding. So the described response—hip and knee flexion when the neck is flexed—maps to Brudzinski's sign.