Sudden weakness and lack of strength in the right hand are usually caused by the following reasons: 1, the most common and most serious often due to acute cerebrovascular disease, such as acute cerebral infarction, acute cerebral hemorrhage and other conditions compressing the motor nerve center, resulting in damage to the upper motor neurons, so there will be dominant motor areas, such as sudden weakness and lack of strength in the right hand. 2, periodic hypokalemic paralysis, there will be sudden numbness and paralysis of the upper limbs bilaterally ear The symptoms of weakness, especially in the bilateral upper limbs. 3, some cervical spondylosis compression for too long will also appear similar to the sudden weakness of the right hand.