Kernig’s sign is seen in –
**Core Concept**
Kernig's sign is a clinical indicator used to assess meningeal irritation by testing the patient's ability to extend their knee while lying on their back with their hip flexed at 90 degrees. This maneuver helps to gauge the presence of meningeal inflammation, which is often associated with conditions such as meningitis.
**Why the Correct Answer is Right**
When Kernig's sign is positive, it indicates that the patient experiences pain or resistance when attempting to extend their knee, suggesting meningeal irritation. This occurs due to the inflammation of the meninges, which are the protective membranes surrounding the brain and spinal cord. In a normal individual, the meninges do not cause pain when stretched, but in cases of meningeal irritation, the inflamed meninges become sensitive to stretching, leading to pain and resistance.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Kernig's sign is not a characteristic feature of lumbar disc herniation. While lumbar disc herniation can cause lower back pain, Kernig's sign specifically tests for meningeal irritation, which is not directly related to this condition.
**Option B:** This option is incorrect because Brudzinski's sign, not Kernig's sign, is often associated with lumbar disc herniation. Brudzinski's sign involves flexion of the hip and knee when the patient's knee is lifted, indicating meningeal irritation.
**Option C:** This option is incorrect because Kernig's sign is not typically associated with conditions such as osteoarthritis or rheumatoid arthritis, which primarily affect the joints.
**Option D:** This option is incorrect because the straight-leg raise test, not Kernig's sign, is used to assess sciatica and lumbar disc herniation. The straight-leg raise test involves lifting the patient's leg to assess for sciatic pain.
**Clinical Pearl / High-Yield Fact**
A positive Kernig's sign is a significant indicator of meningeal irritation, which can be a life-threatening condition if left untreated. It is essential to recognize this sign in patients presenting with symptoms such as headache, fever, and stiff neck.
**Correct Answer:** B. Meningitis