Which sign is triggered by passive neck flexion that causes hip and knee flexion?

Which sign is triggered by passive neck flexion that causes hip and knee flexion?

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

Answer: (B)

Brudzinski's sign is a sign of meningeal irritation. When the neck is passively flexed, the hips and knees involuntarily flex as well. This reflexive movement occurs because irritation of the meninges (as in meningitis) makes the spinal roots respond to neck flexion with protective flexion of the lower extremities. Kernig sign, by contrast, looks for pain or resistance when extending the knee with the hip flexed, not a reflex of neck movement. Nuchal rigidity refers to stiff neck itself, not the reflex hip/knee response. Babinski sign is a separate upper motor neuron sign (toes extending upward when the sole is stroked) and not related to neck flexion triggering leg movements.

Brudzinski's sign is a sign of meningeal irritation. When the neck is passively flexed, the hips and knees involuntarily flex as well. This reflexive movement occurs because irritation of the meninges (as in meningitis) makes the spinal roots respond to neck flexion with protective flexion of the lower extremities.

Kernig sign, by contrast, looks for pain or resistance when extending the knee with the hip flexed, not a reflex of neck movement. Nuchal rigidity refers to stiff neck itself, not the reflex hip/knee response. Babinski sign is a separate upper motor neuron sign (toes extending upward when the sole is stroked) and not related to neck flexion triggering leg movements.