Signal between cortex and spine is carried by upper motor neurons and signal from spine to muscle is carried by lower motor neurons. Upper motor lesions can be seen with: tumors, stroke, ALS, polio and trauma. Lower motor neuron lesion seen in: peripheral neuropathy, poliomyelitis, nerve root compression or trauma. Upper motor neurons lesion presents as: no muscle wasting, hypereflexia with clonus, spasticity, no fasciculation, positive Babinski’s, pronator drift and Hoffman's sign. In lower motor neuron lesion: limited weakness, muscle wasting, absent reflexes, fasciculation and negative Babinski’s. EMG and nerve conduction studies are used to diagnose.