in this report we are going to discuss the following subjects: 1. indications of muscle biopsy in which situation it can not be helpful. 2. how to take a muscle biopsy? 3. how a muscle biopsy should be operated? 4. which techniques do we need to read and interpret a muscle biopsy histologically (h & e staining, histochemical study, electron microscopy). 5. muscle disease histopathologic changes...