Kernig's sign

Overview
Presence of Kernig's sign suggestive of Meningitis.

Original description of Kernig's sign in 1882: During the examination, the patient was seated upright with hips and knees flexed. Kernig would then attempt to extend the patient’s knee. He noted that, in patients with meningitis, he was unable to extend the knee beyond 135 degrees without causing pain.

Today, the maneuver is usually performed with the patient supine with hips and knees in flexion. Extension of the knees is attempted: the inability to extend the patient’s knees beyond 135 degrees without causing pain constitutes a positive test for Kernig’s sign.