Muscle fiber tremor is a stimulation phenomenon of the anterior horn cells of the spinal cord or the motor nucleus of the cranial nerve, and is a small, rapid or peristaltic-like tremor within a few centimeters of the muscle belly of a muscle. It is a continuous fluctuating undulation of the muscle group, caused by continuous spontaneous contraction of the motor unit. When the muscle is denervated, the diseased muscle is very sensitive to acetylcholine in the blood circulation; a small amount of acetylcholine in the blood circulation can cause spontaneous contraction of the muscle fibers and the appearance of myofibrillation potentials that can only be seen on the electromyogram; when similar changes occur in the whole bundle of muscle fibers, the bundle tremor is visible to the naked eye. However, after a certain degree of denervation of the diseased muscle, it no longer presents fascicular fibrillation. 1, common diseases are encephalitis, craniocerebral injury, atherosclerosis, basal ganglia tumor, certain chemical poisoning, such as mercury, manganese chronic poisoning can appear muscle tremor of toxic effects manifestation. 2, physiological tremor. In some cases, most normal people will have subtle rapid tremor in the hand when the two upper limbs are stretched forward flat. Intensification of physiologic tremor can be seen with anxiety, stress, fatigue, metabolic disorders (e.g., alcohol withdrawal, thyrotoxicosis), or the application of certain medications. 3. Primary (benign hereditary) tremor. A subtle to coarse slow tremor that usually affects the hands, head and vocal cords. There is an autosomal dominant factor in 50% of cases. The tremor may be unilateral. The tremor is mild or does not occur at rest and is occasionally incorrectly referred to as senile tremor. 4. Resting tremor in Parkinson’s disease.