L’exploration Fonctionnelle Et L’etude Histologique Quantitative Des Muscles Atrophies*

Abstract

Some methods of electrophysiological and histological exploration that can be used for the clinical diagnosis of muscle atrophies, are described. The excitability of neuromuscular tissue may be expressed graphically by current-duration curves. These curves are different in case of partial and complete denervation. Electromyography reveals some specific modifications of electrical activity in diseased muscles, and may throw some light on the cause of an atrophy. Histopathological alterations of muscle tissue are often lacking specificity, and are of little diagnostic value, when informations about the state of innervation are not available. The pattern of muscular innervation can be studied quantitatively, by the estimation of the terminal innervation ratio and by the measurement of the variations in size and shape of the subneural apparatuses, which represent the post-synaptic part of the myoneural junction. This investigation has been performed on neuromuscular biopsies stained by original histological methods. The modifications occurring in various amyotrophies are described and compared with electromyographic data. The diagnostic value of a quantitative study of terminal motor innervation in cases of chronic partial denervation is pointed out.