Kernig sign
Pronunciation: KERN-ig
Clinical sign of meningeal irritation where passive knee extension with hip flexed at 90 degrees elicits pain and resistance.
Full Definition
Kernig sign is a classic neurological sign used to assess for meningeal irritation, particularly in suspected meningitis or subarachnoid hemorrhage. The test is performed by flexing the patient's hip to 90 degrees and then attempting to extend the knee. A positive Kernig sign occurs when this maneuver elicits pain in the lower back or posterior thigh and resistance to knee extension. The sign reflects irritation of the meninges and nerve roots caused by inflammation or blood in the cerebrospinal fluid. While historically considered important for diagnosing meningitis, modern studies show variable sensitivity and specificity. Clinical documentation should describe the exact technique used and the patient's response, as the sign can be present in other conditions causing back pain or nerve root irritation.
Usage
Usage note: Named after Vladimir Kernig. Often tested alongside Brudzinski sign; both assess meningeal irritation but use different techniques.
In Context
- "Physical examination was notable for positive Kernig and Brudzinski signs, raising concern for meningeal irritation." — Emergency department evaluation
- "The patient's Kernig sign became negative following treatment for bacterial meningitis." — Infectious disease follow-up