Numbness of the right arm is not a symptom of any disease, it may be an early or typical manifestation of cerebrovascular disease, radiculopathy, diabetes-induced peripheral neuropathy and other diseases. 1. Cerebrovascular disease: cerebral ischemia and cerebral infarction can damage the sensory cortex and sensory conduction pathway of the patient’s brain, thus causing the patient to experience numbness, tingling, and other sensory disorders in one side of the limb. 2. Neurogenic cervical spondylosis: arm sensation is innervated by the brachial plexus nerve, therefore, patients with neurogenic cervical spondylosis can suffer from numbness of one side of the arm due to abnormal function of the brachial plexus nerve caused by compression of one side of the cervical nerve root by the protruding cervical intervertebral disc. 3. Diabetes-induced peripheral neuropathy: Diabetes-induced chronic hyperglycemia may lead to a variety of physiopathological changes in patients, causing neurological damage to patients, peripheral neuropathy, so patients may experience numbness of the limbs, tingling and other symptoms. It is recommended that patients with numbness of the arm should consult a doctor in time to clarify the specific cause of numbness of the arm and carry out targeted treatment in time.