Arm nerves have been jumping may be arm muscles in the beating: one, may be caused by overwork. Arm long time lifting heavy objects can easily cause arm muscle overwork, muscle involuntary jumping and trembling, generally as long as the appropriate rest after a period of time can be restored. Secondly, if the arm muscle jumps frequently, there may be anterior horn cell injury symptoms. Such as cervical spinal cord cavernous disease, motor neuron disease in amyotrophic lateral sclerosis and progressive spinal muscular atrophy, cervical cord tumors, poliomyelitis, etc., can appear arm muscle jumping, it is recommended to do electromyography examination or cervical cord MRI. Third, other calcium deficiency, calcium ions will lead to increased neuromuscular excitability, easy to appear muscle jumping, it is recommended that the biochemical calcium ion test. Fourth, the cause of arm muscle throbbing may also be peripheral neuritis, which is due to limb peripheral nerve damage caused by neurosensory disorders due to the phenomenon. Fifth, arm nerves have been jumping may also be the blood vessel beat, and this beat is generally consistent with the rhythm of the heart beat, clinically common in people who often exercise and part of the hypertensive patients.