Which sign is positive when leg extension cannot occur after 90 degrees of hip flexion?

Which sign is positive when leg extension cannot occur after 90 degrees of hip flexion?

• A. Kernig's sign
• B. Brudzinski's sign
• C. Babinski sign
• D. Romberg

Answer: (A)

Kernig's sign is being tested. When a patient has meningitis or meningeal irritation, extending the knee while the hip is flexed to 90 degrees often triggers pain and prevents full leg extension. The procedure involves lying supine, flexing the hip and knee to 90 degrees, then slowly straightening the knee. A positive result is pain or resistance to extension, reflecting irritation of the meninges and spinal nerve roots from inflammation or other intracranial processes. This sign is part of the meningeal irritation constellation and helps distinguish it from other neurological signs. Brudzinski's sign is a different maneuver in which neck flexion causes involuntary flexion of the hips and knees, also suggesting meningeal irritation but via a separate reflex pathway. Babinski sign is an abnormal plantar response indicating an upper motor neuron lesion, not specific to meningitis. Romberg assesses balance and proprioception, not meningeal irritation.

Kernig's sign is being tested. When a patient has meningitis or meningeal irritation, extending the knee while the hip is flexed to 90 degrees often triggers pain and prevents full leg extension. The procedure involves lying supine, flexing the hip and knee to 90 degrees, then slowly straightening the knee. A positive result is pain or resistance to extension, reflecting irritation of the meninges and spinal nerve roots from inflammation or other intracranial processes. This sign is part of the meningeal irritation constellation and helps distinguish it from other neurological signs.

Brudzinski's sign is a different maneuver in which neck flexion causes involuntary flexion of the hips and knees, also suggesting meningeal irritation but via a separate reflex pathway. Babinski sign is an abnormal plantar response indicating an upper motor neuron lesion, not specific to meningitis. Romberg assesses balance and proprioception, not meningeal irritation.