The maneuver described as placing the patient supine, lifting the relaxed leg with hip flexion, and dorsiflexing the foot is known as which test?

The maneuver described as placing the patient supine, lifting the relaxed leg with hip flexion, and dorsiflexing the foot is known as which test?

• A. Kernig's sign
• B. The straight-leg raise
• C. The plantar response
• D. The ankle reflex

Answer: (B)

This maneuver tests for nerve root irritation from a lumbar disc herniation, typically L5–S1. Lifting the leg with the knee extended stretches the sciatic nerve and lumbosacral nerve roots; if radicular pain radiates down the leg, especially below the knee, it’s a positive sign. Dorsiflexing the foot during the maneuver increases nerve tension and can bring on or amplify the pain, strengthening the finding of nerve involvement. This helps distinguish radicular pain from simple local muscle pain. Kernig's sign involves loading the meninges and presents differently, often with hamstring discomfort and pain upon knee extension after hip/knee flexion, not a nerve root stretch. The plantar response and ankle reflex assess different neural pathways (upper motor neuron signs and reflexes) and do not specifically test lumbar nerve root tension.

This maneuver tests for nerve root irritation from a lumbar disc herniation, typically L5–S1. Lifting the leg with the knee extended stretches the sciatic nerve and lumbosacral nerve roots; if radicular pain radiates down the leg, especially below the knee, it’s a positive sign. Dorsiflexing the foot during the maneuver increases nerve tension and can bring on or amplify the pain, strengthening the finding of nerve involvement. This helps distinguish radicular pain from simple local muscle pain.

Kernig's sign involves loading the meninges and presents differently, often with hamstring discomfort and pain upon knee extension after hip/knee flexion, not a nerve root stretch. The plantar response and ankle reflex assess different neural pathways (upper motor neuron signs and reflexes) and do not specifically test lumbar nerve root tension.