Atrophy, << AT ruh fee, >> is the normal or abnormal shrinking of any part of the body. Some body tissues may shrink in size as a result of disease. For example, progressive muscular atrophy, a disease of a part of the spinal cord, causes certain muscles to atrophy. People with this disease lose the ability to move their arms and legs. The name atrophy comes from two Greek words meaning not nourished.