Frequent throbbing of the left hand at the muzzle can be caused by local muscle exertion, anterior horn cell lesion of the spinal cord, and cervical spinal cord disease. 1. Localized muscle exertion: over-exertion or calcium deficiency of the muscles of the left hand at the muzzle can lead to increased muscle excitability, triggering muscle spasms, resulting in involuntary muscle throbbing at the muzzle. 2. Spinal cord anterior horn cell lesions: degeneration of the anterior horn cells of the spinal cord can lead to abnormal nerve discharges, triggering involuntary contraction of the local muscles, which can lead to muscle spasm and throbbing, and then the symptoms. 3. Cervical spinal cord disease: spinal cord occupation or myelitis, etc., can cause involuntary local muscle throbbing, can also be accompanied by muscle weakness and sensory deficits and other manifestations. If the throbbing in your left hand does not get better, you should consult a doctor in time, and under the guidance of the doctor, you can improve the discomfort symptoms as soon as possible.