Monoparesis may occur with central and peripheral nervous system lesions. Hemiparesis due to a single lesion occurs exclusively with central nervous involvement. Peripheral lesions involving the brachial plexus and the lumbar plexus on the same side can produce hemiparesis but they are very rare. Decreased limb movements of both upper extremities (upper extremity diparesis) usually results from bilateral brachial plexus lesions. Bilateral lower extremity weakness usually implies a lesion in the thoracic spine, conus, or cauda equina. Quadriparesis usually results from cervical spine lesions, although diseases of the anterior horn motor neurons (Werdnig-Hoffmann disease) may produce similar findings. More about...132