Atrophy: A wasting away or diminution. Muscle atrophy is a decrease in muscle mass, often due to extended immobility. From Healthy Resources 10 Rheumatoid Arthritis Symptoms How IL Inhibitors Work to Treat PsoriasisModerate to Severe UC: Targeted Solutions Featured Centers What Are the Best PsA Treatments for You?Understanding Biologics 10 Things People With Depression Wish You Knew