Numbness of the patient’s right arm and leg is commonly caused by cervical spondylosis and brain lesions, as follows: First, cervical spondylosis: patients suffering from cervical spondylosis, cervical disc herniation, lumbar spinal stenosis, lumbar disc herniation and other related diseases at the same time will have cervical nerve and lumbar nerve compression, and therefore will have numbness symptoms of the right upper and lower limbs, which will be accompanied by muscle weakness. Early treatment can lead to complete relief of clinical symptoms, while a longer course of the disease and delayed treatment can lead to difficulty in relieving numbness symptoms. Second, brain lesions: severe brain lesions, such as cerebral infarction, cerebral hemorrhage and other compression of the central nervous system, can also cause numbness symptoms in the opposite arm and leg, accompanied by limb weakness and skin sensory disorders, and the diagnosis can generally be confirmed by CT examination or MRI. Therefore, patients with numbness in the right upper and lower extremities should pay high attention and receive timely treatment.