A patient with meningitis demonstrates pain when attempting to straighten the knee with the hip flexed.

A patient with meningitis demonstrates pain when attempting to straighten the knee with the hip flexed.

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

Answer: (A)

Kernig sign reflects irritation of the meninges from meningitis. To test it, you have the patient lie on the back with the hip flexed to about 90 degrees, then attempt to straighten the knee. If extending the knee causes pain and resistance (or cannot be fully extended), the sign is considered positive. The reason this occurs is that meningeal inflammation makes the dura and nerve roots more sensitive to stretch; extending the knee when the hip is flexed lengthens the meninges and the nerve roots, provoking pain. This helps distinguish meningeal irritation from other signs. Brudzinski sign involves involuntary flexion of the hips and knees when the neck is flexed. Nuchal rigidity refers to stiffness of the neck itself. Babinski sign is an upgoing plantar response indicating an upper motor neuron lesion, not meningeal irritation. In meningitis, Kernig sign is a classic indicator of meningeal irritation.

Kernig sign reflects irritation of the meninges from meningitis. To test it, you have the patient lie on the back with the hip flexed to about 90 degrees, then attempt to straighten the knee. If extending the knee causes pain and resistance (or cannot be fully extended), the sign is considered positive. The reason this occurs is that meningeal inflammation makes the dura and nerve roots more sensitive to stretch; extending the knee when the hip is flexed lengthens the meninges and the nerve roots, provoking pain. This helps distinguish meningeal irritation from other signs.

Brudzinski sign involves involuntary flexion of the hips and knees when the neck is flexed. Nuchal rigidity refers to stiffness of the neck itself. Babinski sign is an upgoing plantar response indicating an upper motor neuron lesion, not meningeal irritation. In meningitis, Kernig sign is a classic indicator of meningeal irritation.