Myogenic damage refers to damage caused by lesions in the muscle itself, prominently represented by polymyositis and progressive muscular dystrophy. It is characterized by damage to muscle fibers, which reduces the number of muscle fibers in the motor unit.
Electromyography of myogenic damage is characterized by a shortening of the average duration of motor unit action potentials by more than 20% of the normal value, accompanied by a decrease in wave amplitude, an increase in polyphasic potentials, and a pathological disturbed phase during vigorous contraction.
Muscle biopsy shows that myofibers are of different sizes, with atrophic fibers and hypertrophic fibers in between, and that the nuclei can be seen to be shifted inward, granular degeneration, flocculent degeneration, vacuolar degeneration and phagocytosis.
Some of the myogenic damage can be cured, while some cannot be cured and can only relieve the symptoms. In traumatic myogenic damage, if the injury is mild, it can be gradually relieved by conservative treatments such as physical therapy, massage, traction, braking, and medication. For more severe injuries, such as muscle ruptures and lacerations, surgery is required.