Light micrograph of human muscle showing neurogenic muscular atrophy. Wasting of skeletal muscle may be caused by primary muscle disease or (as here) secondary to motor nerve damage. Only those muscle fibres supplied by damaged motor neurones (nerves) become small & atrophic (wasted), appearing arranged in distinct groups. In this image, large normal muscle fibres appear at left, with small, atrophic fibres at right. This pattern contrasts to that of muscular dystrophy, where atrophic muscle fibres are scattered randomly amongst the larger, normal fibres.