Kernig's sign is a test used in physical examination to look for evidence of
irritation of the meninges. The test involves flexing the thighs at the hip, and the knees, at 90 degree angles, and assessing whether subsequent extension of the knee is painful (leading to resistance), in which case it is deemed positive. This may indicate
subarachnoid haemorrhage
Subarachnoid hemorrhage (SAH) is bleeding into the subarachnoid space—the area between the arachnoid membrane and the pia mater surrounding the brain. Symptoms may include a severe headache of rapid onset, vomiting, decreased level of cons ...
or
meningitis. Patients may also show
opisthotonus—spasm of the whole body that leads to legs and head being bent back and body bowed forward.
Karl et al. noted much of the literature on Kernig's sign is old and they could find no randomised trials of it. They also noted low
Sensitivity of 5% meaning absence of Kernig's sign does not rule out meningitis, specificity however is 95% so if positive then meningitis is very likely. Kernig's should not be relied on when meningitis is suspected and a
Lumbar puncture should be performed.
Name
The test is named after
Woldemar Kernig (1840–1917), a Russian neurologist.
See also
*
Brudziński's sign
References
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Medical signs