Babinski's reflex occurs when the big toe moves toward the top of the foot and the other toes fan out after the sole of the foot has been firmly stroked.

This reflex, or sign, is normal in younger children, but abnormal after the age of 2.

Reflexes are specific, predictable, involuntary responses to a particular type of stimulation.

Babinski's reflex is one of the infantile reflexes. It is normal in children up to 2 years old, but it disappears as the child ages and the nervous system becomes more developed. It may disappear as early as 12 months.

The presence of a Babinski's reflex after age 2 is a sign of damage to the nerve paths connecting the spinal cord and the brain (the corticospinal tract). This tract runs down both sides of the spinal cord, therefore a Babinski's reflex can occur on one side or on both sides.

An abnormal Babinski's reflex can be temporary or permanent.

• Generalized tonic-clonic seizure (there may be a temporary Babinski's reflex for a short time after a seizure)
• Amyotrophic lateral sclerosis (Lou Gehrig's disease)
• Brain tumor (if it injures or puts pressure on the corticospinal tract)
• Familial periodic paralysis
• Friedreich's ataxia
• Head injury
• Hepatic encephalopathy
• Meningitis
• Multiple sclerosis
• Pernicious anemia
• Poliomyelitis (some forms)
• Rabies
• Spinal cord injury
• Spinal cord tumor
• Stroke
• Syringomyelia
• Tuberculosis (when it affects the spine)