What indicates a positive Kernig sign during an examination?

A positive Kernig sign is indicated by pain and resistance to knee extension when the hip is flexed at 90 degrees. This sign is particularly significant in the assessment for meningeal irritation, commonly associated with conditions such as meningitis. When a clinician performs the Kernig test, they position the patient with the hip flexed and then attempt to straighten the knee. If the patient experiences pain or is unable to extend the knee fully due to discomfort, it suggests irritation of the meninges.

The presence of pain and resistance demonstrates that there is potential inflammation affecting the nervous system, which is critical information for diagnosing central nervous system issues. Therefore, this clinical sign is a useful indicator for healthcare providers when evaluating a patient with symptoms suggestive of meningeal irritation.