Atrophy: A wasting away or diminution. Muscle atrophy is a decrease in muscle mass, often due to extended immobility. From Healthy Resources How IL Inhibitors Work to Treat PsoriasisModerate to Severe UC: Targeted SolutionsExpert Insight on a New Treatment for C3G Featured Centers What Are the Best PsA Treatments for You?Understanding Biologics 10 Things People With Depression Wish You Knew