Babinski Test: Screening for Upper Motor Neuron Lesions

The Babinski Test (Plantar Reflex) is a fundamental neurological exam. It is used to determine if there is damage to the central nervous system (Upper Motor Neurons), distinguishing it from peripheral nerve injuries.

1. Purpose

The primary purpose of the Babinski Test (Plantar Reflex) is to **check for** an Upper Motor Neuron (UMN) lesion. It assesses the integrity of the corticospinal tract (pyramidal tract). It helps distinguish between brain/spinal cord issues (UMN) and nerve root/peripheral nerve issues (LMN).

2. How to Perform

1. The patient is positioned in supine or sitting with the foot relaxed.
2. The examiner uses a blunt object (like the handle of a reflex hammer, a key, or a tongue depressor).
3. The examiner firmly strokes the lateral aspect of the sole of the foot, starting from the heel, moving up towards the little toe, and then curving medially across the ball of the foot towards the big toe (following the path of the dermatomes).

3. Positive & Negative Sign

Positive Sign (Pathological in adults):
A positive Babinski sign is indicated by:

• Extension (dorsiflexion) of the big toe (it moves upward).
• Fanning (abduction) of the other four toes.
• This indicates a UMN lesion (e.g., spinal cord injury, stroke, MS). Note: This is normal in infants up to ~12-18 months.

Negative Sign (Normal in adults):
A negative (normal) response is the flexion (curling) of the toes downwards.