Skeletal muscle diseases refer to lesions that occur within the skeletal muscle. They mainly include lesions of the skeletal muscle itself and other systemic diseases. 1. Skeletal muscle itself: mainly includes polymyositis, dermatomyositis, congenital muscle disease, progressive muscular dystrophy, dystrophic muscular dystrophy, wasting muscular dystrophy, ischemic muscular dystrophy and so on. Mild patients may have morphological and functional changes in skeletal muscle; heavy patients may have pain, stiffness, weakness or even dysfunction. 2. Other systemic diseases: mainly including various types of endocrine diseases, such as mitochondrial encephalomyopathy, lipid deposition myopathy, glycogen accumulation disease, etc.; immune system diseases, such as rheumatism, rheumatoid rheumatism, ankylosing spondylitis, etc.; neuronal lesions, such as cerebral hemorrhage, poliomyelitis, etc.. Skeletal muscle disease may also have other diseases, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.