A disorder affecting the upper motor neuron of the pyramidal tract may result in a number of clinical findings.
Neuro-anatomic involvement: corticospinal tracts
Manifestations:
(1) spasticity
(2) weakness
(3) slowing of rapid alternating movements
(4) hyperreflexia
(5) Babinski's sign: extension of the great toe and fanning of the toes after plantar stimulus, rather than flexion
(6) Hoffmans's sign: flexion movement of the thumb and index finger when the fingernail of the middle finger is flicked down
The Babinski and Hoffman signs are "normal" up until the age of 2, after which myelination is complete.
