Kernig sign
A clinical hallmark of meningitis, inflammation of the meninges, the membranes covering the brain and spinal cord.</P> The test for Kernig sign is done by having the person lie supine (flat on the back), flex the thigh so that it is at a right angle to the trunk, and completely extend the leg at the knee joint.
If the leg cannot be completely extended due to pain, this is Kernig sign.