Involuntary twitching of the right thumb is generally associated with hypocalcemia, muscle fatigue, and may also be associated with Parkinson’s disease and idiopathic tremor. 1. Hypocalcemia: When there is insufficient free calcium in the body, it may trigger an increase in neuromuscular excitability, and myoclonic spasms may occur. The early stage of peripheral nervous system may be manifested as numbness of fingers (toes) or involuntary hand twitching. 2. Muscle spasm: It is often caused by overworked hand muscles and fascial tension, which may result in localized pain or swelling and involuntary twitching. 3. Parkinson’s Disease: A common symptom of Parkinson’s Disease patients is a resting tremor with slow movements. Therefore, the patient’s right thumb will keep twitching, and the symptom will be aggravated when resting or under emotional stress. 4. Idiopathic tremor: One of the symptoms of this movement disorder is involuntary tremor of the limb muscles, and the patient usually has twitching of the right thumb. It should be noted that if the twitching of the fingers is not relieved on its own, and persists for a long time, it is recommended to go to the hospital in time to avoid delaying the condition and affecting the treatment.