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Babinski's Sign or Extensor Plantar Response

The Babinski sign can indicate upper motor neuron lesion constituting damage to the corticospinal tract
In 1896 Babinski first described this sign.
Joseph Francois Felix Babinski was a French physician cum neurologist. It is considered as the sign in Neurology
The response are dorsiflexion and extension of great toe.The movement occur at the metatarsophalangeal joint.This is the first movement that precedes all the other movements 
On eliciting the plantar response, there is dorsiflexion of the great toe, along with extension and fanning out of the other toes.
In addition, especially if the extensor response is marked, there is dorsiflexion at the ankle, with flexion at the knee and hip, these associated movements being brought about by contraction of the anterior tibial. hamstrings, and tensor fascia lata.
The Babinski's sign can be elicited only by stroking the lateral aspect of the dorsum of foot in the following situations.
  • Presence of minimal pyramidal tract lesion, 
  • In individuals with thick soles.
The Babinski sign can be elicited over the medial aspect of the foot when the lesion becomes dense (this is due to increase in the reflexogenic area).
If no plantar response can be elicited with the patient's knee flexed and thigh externally rotated, it can be elicited by extending the patient's knee, or even applying pressure on the knee (thigh being in the neutral position). .
With repeated stimulation of the sole of the foot, the plantar response may become fatigued, and the extensor plantar response may not be elicitable.
The components of extensor plantar response is 
Components are 
  • Extension of big toe
  • Extension of other toes and fanning
  • Dorsiflexion and eversion
  • Flexion of knee and hip joint. 

The only visible response may be dorsiflexion of big toe, contraction of other muscles can be felt by palpation.