Stroking the lateral part of sole of the foot with a fairly sharp object produces plantar flexion of the big toe; often there is also flexion and adduction of the other toes. This is normal, flexor plantar reflex.
In some patients, stroking the sole produces extension of the big toe, often with extension and abduction of the other toes. This abnormal response is termed, the extensor plantar reflex, or Babinski reflex.
Babinski reflex is a classic sign of upper motor lesion.
