MEDICAL DICTIONARY

Table of Contents

Babinski test

The Babinski test is a neurological examination used to evaluate the function of the corticospinal (pyramidal) tract. It assesses the response of the toes to stimulation of the sole of the foot and helps in diagnosing central nervous system abnormalities, particularly upper motor neuron lesions.

Procedure

  1. The patient is positioned lying down or seated with legs extended.
  2. A blunt object, such as the handle of a reflex hammer, is used to stroke the lateral sole of the foot.
  3. The stroke begins at the heel, moves along the outer edge of the sole, and curves toward the ball of the foot.

Interpretation

  • Normal Response (Negative Babinski Sign): The toes curl downward (plantar flexion) or show no significant movement.
  • Abnormal Response (Positive Babinski Sign): The big toe dorsiflexes (points upward), and the other toes fan out. This response is abnormal in adults and is considered a sign of corticospinal tract dysfunction.

Clinical Significance

A positive Babinski sign can indicate:

  • Upper motor neuron lesions
  • Stroke
  • Multiple sclerosis
  • Amyotrophic lateral sclerosis (ALS)
  • Brain or spinal cord injury
  • Other central nervous system disorders

In infants up to 12-24 months, a positive Babinski sign is normal due to incomplete myelination of the corticospinal tract.

Historical Background

The test is named after Joseph Babinski, a French neurologist who described the reflex in 1896. His work laid the foundation for its use as a diagnostic tool in neurology.

References
  1. Babinski, J. (1896). Sur le réflexe cutané plantaire dans certaines affections organiques du système nerveux central. Bulletin de la Société de Biologie, 48, 207–208.
  2. Prasad, K., & Gray, M. (2006). The Babinski sign – A review. Neurology India, 54(1), 1–5. doi:10.4103/0028-3886.25089
  3. Chitnis, T., & Syc, S. (2012). Neurological examination: A primer. Current Opinion in Neurology, 25(4), 491–498. doi:10.1097/WCO.0b013e328355c8b5