Muscular atrophy is a symptom characterized by the loss of normal muscle mass. It is caused by a decline in the total number of muscle cells, or by a substantial decline in the substance of individual muscle cells. It has been associated with a preceding muscle weakness. Muscular atrophy occurs late in the course of a disease. Due to the limited ability of muscle cells to regenerate, it is frequently irreversible. Hence the aim is to detect the early stages of muscular decline and to prevent outright muscular atrophy. To achieve this it is necessary to be aware of the large number of diseases that can induce this in order to ensure timely referral to a specialist.