Kernig's Sign

Description[edit | edit source]

Overview of the meninges of the brain (coronal view)

Kernig's sign is one of the physically demonstrable symptoms of meningitis. Severe stiffness of the hamstrings causes an inability to straighten the leg when the hip is flexed to 90 degrees.[1]

Image: Overview of the meninges of the brain (coronal view)[2]

Purpose[edit | edit source]

Kernig's sign is used to diagnose meningitis

Technique[edit | edit source]

To elicit the Kernig's sign[3]

Step 1. The patient is positioned in supine with hip and knee flexed to 90 degrees

Step 2. The knee is then slowly extended by the examiner (Repeat on both legs)

Step 3. Resistance or pain and the inability to extend the patient's knee beyond 135 degrees, because of pain, bilaterally indicates a positive Kernig's sign

Evidence[edit | edit source]

The study was done on 297 adults with suspected meningitis to determine the diagnostic accuracy of Kernig's sign, Brudzinski's sign, and Nuchal rigidity for meningitis And the study shows kernig's sign has diagnostic value of

Sensitivity 5%[4]

Specificity 95%[4]

Positive predictive value 27%[4]

Negative predictive value 72%[4]

The results of this study shows that the diagnostic accuracy of Kernig's sign and Brudzinski's sign was poor for patients with moderate and severe meningeal inflammation and patients with microbiological evidence of CSF infection. And also patients with severe meningitis on the basis of laboratory evidence both Kernig's sign and Brudzinski's sign as low diagnostic value.[4]

Another study suggest that Kernig's sign and Brudzinski's sign as low sensitivity and high specificity for diagnosing meningitis.[5]

  • Low sensitivity suggest when both signs absent should not conclude that there is no evidence of meningitis[5]
  • High specificity suggest when both signs are present there is a high likelihood for meningitis.[5]
  • In clinical practice both kernig's and brudzinski's sign are frequently performed together.[5]

References[edit | edit source]

  1. MedlinePlus. Kernig's sign of meningitis. Available from: (accessed 1 August 2021).
  2. Overview of the meninges of the brain (coronal view) image - © Kenhub
  3. Brunner & Suddarth's Textbook of Medical-surgical Nursing, Volume 1. edited by Suzanne C. O'Connell Smeltzer, Brenda G. Bare, Janice L. Hinkle, Kerry H. Cheever. Lippincott Williams & Wilkins, 2010
  4. 4.0 4.1 4.2 4.3 4.4 Thomas KE, Hasbun R, Jekel J, Quagliarello VJ. The diagnostic accuracy of Kernig's sign, Brudzinski's sign, and nuchal rigidity in adults with suspected meningitis. Clinical Infectious Diseases. 2002 Jul 1;35(1):46-52.
  5. 5.0 5.1 5.2 5.3 Mehndiratta M, Nayak R, Garg H, Kumar M, Pandey S. Appraisal of Kernig's and Brudzinski's sign in meningitis. Annals of Indian Academy of Neurology. 2012 Oct;15(4):287.