Purpose of Kernig’s sign: To determine if the patient has inflammation of the meninges (meningitis) (1).

Patient position: Lying supine (conventional practice). VM Kernig originally elicited this sign by having the patient in sitting position.

Examiner position: Standing beside the bed, facing the patient.

Procedure: With the patient lying supine, flex one of the patient’s legs (hip and knee joints) to 90 degrees, and then slowly extend the knee beyond 90 degrees.

Outcome: The presence of pain and/or resistance on a further extension of the knee joint (typically more than 130 degrees) constitutes a positive Kernig’s sign (1, 2). 

References:

1. Kernig V. Ueber ein kankheits symptom der acuten meningitis. St Petersburgh Medizinische Woschenschrift. 1882;7:398.
2. Kernig W. Ueber ein Wenig Bemerktes Meningitis- Symptom. Berlin Klin Wschr. 1884;21:829 – 32.