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Babinski's reflex

Definition

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.

Alternative Names

Reflex - Babinski's; Extensor plantar reflex; Babinski's sign

Considerations

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.

Common Causes

• 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)

Home Care

Typically, a person (older than an infant) who has a Babinski's reflex will also have incoordination, weakness, and difficulty with muscle control. Safety is important to prevent the risk of injury. The person may need assistance with activity, and the environment should be kept free of hazards.

Call your health care provider if

This finding is usually discovered by the health care provider, and the affected person usually is not aware of its presence.

What to expect at your health care provider's office

The health care provider will perform a physical exam and ask questions about the patient's symptoms and medical history.

The physical examination will include a complete nervous system (neurological) examination.

Diagnostic testing may include:

• MRI scan of the head or MRI scan of the spine
• Angiography of the head
• Somatosensory evoked potentials
• Lumbar puncture and analysis of the cerebrospinal fluid

References

Griggs R, Jozefowicz R, Aminoff M. Approach to the patient with neurologic disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 418.

Hammerstad J. Strength and reflexes. In: Goetz, CG, ed. Textbook of Clinical Neurology. 3rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 15.