A physical examination finding elicited by stroking the sole of the foot with a blunt, narrow tool (e.g., handle of a reflex hammer) from the lateral heel up to the base of the small toe, then medially across the bases of the toes, following a "J" path. A normal response to the stimulus in adults is plantarflexion of all toes; a pathologic response is extension of the hallux with abduction of all toes and indicates corticospinal tract damage. A positive Babinski sign (hallux extension) is normal up to the age of approx. 2 years.