kernige

Kernig sign, also known as Kernig’s sign, is a clinical sign historically used to indicate meningeal irritation, typically from meningitis. It is elicited by examining a patient who is lying supine. The examiner flexes the patient’s hip and knee to 90 degrees and then attempts to extend the knee. A positive sign consists of marked resistance to extension and often pain in the hamstrings or lower back.

The sign is named after Vladimir Mikhailovich Kernig, a Russian physician who described it in the late 19th century. It reflects irritation of the meninges rather than a specific disease, and its presence suggests meningeal irritation but is not diagnostic of meningitis by itself.

Clinical value and limitations: Kernig’s sign has limited sensitivity and specificity. Many patients with meningitis may have a negative sign, especially in early disease or in certain populations, and some non-meningeal conditions (such as lumbar spine or hip pathology) can produce a positive result. Because it is not highly reliable, Kernig’s sign is used as part of a broader neurological assessment rather than as a sole diagnostic test.

In modern practice, suspected meningitis is investigated with prompt clinical evaluation and, when indicated, lumbar puncture with cerebrospinal fluid analysis. Signs like Kernig’s and Brudzinski’s remain part of the historical and clinical exam but should not delay definitive testing and treatment.