Babinski sign HP:0003487 HP:0001352 Positive Babinski sign Extensor plantar reflexes Upturning of the big toe (and sometimes fanning of the other toes) in response to stimulation of the sole of the foot. If the Babinski sign is present it can indicate damage to the corticospinal tract. Extensor plantar response UMLS:C0034935 A positive Babinski sign can indicate damage to the corticospinal tract. SNOMEDCT_US:246586009 Extensor plantar responses SNOMEDCT_US:366575004 Abnormal pyramidal sign Abnormal superficial reflex