atrophy, diminution in the size of a cell, tissue, or organ from its fully developed normal size. Temporary atrophy may occur in muscles that are not used, as when a limb is encased in a plaster cast. Interference with cellular nutrition, as through starvation; diseases affecting the nerve supply of tissues, e.g., poliomyelitis and muscular dystrophy; and prolonged disuse may cause a permanent wasting away of tissue. Atrophy may also follow hypertrophy.

Decrease from previous normal size of the body or a part, cell, organ, or tissue. An organ or body part's cells may be reduced in number, size or both. Atrophy of some cells and organs is normal at certain points in the life cycle. Other causes include malnutrition, disease, disuse, injury, and hormone over- or underproduction.

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