Kernig and Brudzinski signs
Kernig and Brudzinski signs are bedside physical exam maneuvers used to assess meningeal irritation in suspected meningitis. [1] These signs reflect pain or involuntary movement when passive motions increase strain on the meninges. [1]
Kernig sign
Kernig sign is elicited with the patient supine. [1] Hip flexion and knee flexion are performed to 90 degrees. [1] Knee extension is then attempted. [1] A positive Kernig sign is resistance to knee extension and/or pain in the setting of suspected meningeal irritation. [1]
Brudzinski sign
Brudzinski sign is elicited by flexing the upper trunk of a supine patient. [1] In the setting of meningeal irritation, involuntary flexion of both knees occurs in response to neck flexion or upper trunk flexion. [1] This knee flexion in response to attempted neck flexion is considered a positive Brudzinski sign. [1]
Clinical context
Kernig and Brudzinski signs are described as classic meningeal signs alongside nuchal rigidity. [2] Diagnostic accuracy can be limited, and these signs should be interpreted in conjunction with clinical assessment. [3]
Practical interpretation
Both signs are manifestations of meningeal irritation and are most clinically useful as part of an overall evaluation for meningitis. [2] Negative results do not exclude meningitis. [3]