Disorders of the Peripheral Motor System

Abstract

The principal entities in the differential diagnosis of the peripheral motor system are primary muscle and lower motor neuron disorders.

Primary muscle disease is associated with wasting and weakness. Hypotonicity and diminution of deep reflexes parallel the muscle wasting, and muscle groups are involved bilaterally.

Lower motor neuron disorders cause changes reflecting loss of nerve supply to the muscles. Fasciculations and denervation fibrillation are present. Trophic changes of the skin and nails often occur.