Hemiplegic atrophy

LOSS OF MUSCLE BULK may result from primary diseases of muscle (myopathy), disorders of the lower motor neuron (neural atrophy), disturbances of suprasegmental influences (“central” atrophy), and a heterogenous group of conditions in which debilitation or immobilization are present (“disuse” atrophy). Myopathy and neural atrophy are readily diagnosed by histological examination, and much is known about their pathophysiology. In contrast, the histological observations in central atrophy and disuse atrophy are sparse, and the two frequently are grouped together as possessing a common etiologic mechanism. The purpose of this report is to describe the histopathology of atrophy, secondary to hemiplegia, resulting from a cerebral vascular accident. This atrophy is usually considered to be the result of disuse of the paralyzed extremity. In some instances, parietal lobe dysfunction with a resulting loss of “trophic” influences on muscle is held as causal. Evidence is presented to question the importance of disuse as a major factor, and the literature concerning atrophy of suprasegmental origin is reviewed.