Advanced microscopic and histochemical techniques: diagnostic tools in the molecular era of myology.

Over the past two centuries, myology (i.e. the basic and clinical science of muscle and muscle disease) has passed through 3 stages of development: the classical period, the modern stage and the molecular era. The classical period spans the last part of nineteenth century and the earlier part of the twentieth century. During this time, several major muscle diseases were clinically and pathologically characterized, including Duchenne muscular dystrophy (DMD), myotonic dystrophy (DM) and facioscapulohumeral dystrophy (FSHD). The modern stage in the second half of the twentieth century is characterized by the adaptation of histo and cytochemical techniques to the study of muscle biopsies. These tools improved the diagnostic accuracy and made possible the identification of new changes and structures (Engel and Cunningham, 1963; Scarlato, 1975).