Which sign is tested by neck flexion causing involuntary hip and knee flexion?

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

Answer: (A)

Neck flexion causing involuntary hip and knee flexion is Brudzinski's sign, a classic finding of meningeal irritation. When the neck is passively flexed in a supine patient, the hips and knees automatically bend as a reflex response, suggesting irritation of the meninges from conditions like meningitis or subarachnoid hemorrhage. This is distinct from Kernig's sign, which involves pain and resistance to extending the knee when the hip is flexed, also related to meningeal irritation but tested differently. Babinski sign is a dorsal-plantar response indicating an upper motor neuron lesion, and Romberg assesses balance and proprioception by having the patient stand with feet together and eyes closed.