Which sign indicates meningeal irritation when neck flexion causes involuntary flexion of the hips and knees?

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

Answer: (D)

Meningeal irritation triggers reflexive body movements when the meninges are stretched. The sign where passive neck flexion causes the hips and knees to flex involuntarily is Brudzinski's sign. It indicates irritation of the meninges, as seen with meningitis or subarachnoid hemorrhage. To assess it, you have the patient lie flat and gently flex the neck; if the hips and knees automatically bend, the sign is positive. This differs from Kernig's sign, where pain or resistance occurs when extending the knee with the hip flexed at 90 degrees, another manifestation of meningeal irritation but via a different maneuver. Romberg tests balance and proprioception, not meningeal irritation, and Babinski reflects an upper motor neuron lesion through the plantar response.