DESCRIPTION

• Motor weakness may be a manifestation of neurologic disease or general medical illness. Within neurologic diseases, motor weakness can result from dysfunction in the central nervous system (CNS) or the peripheral nervous system (PNS). The PNS includes the anterior horn cells, nerve roots, neuromuscular junction, and muscle.
• Etiologies of motor weakness are varied. History and exam localize motor weakness.
• The time course of symptom onset and the pattern of weakness narrow the differential diagnosis and guide the next steps.