Numbness of the right index finger, i.e. unilateral numbness of the index finger or unilateral numbness of the limbs, the main cause is peripheral nerve injury, the most common causes: 1, cervical spondylosis, or called cervical spine degeneration, due to cervical vertebral degeneration or disc protrusion, compression of the cervical cord dural sac, resulting in dysfunction of the corresponding spinal cord innervation area, the most common is numbness in the limbs, and some people will experience pain or weakness of the limbs and finger weakness, dysfunction. Endocrine metabolic disorders, such as diabetic peripheral neuropathy is also prone to cause numbness of the limbs, especially hands or feet; 3, carpal tunnel syndrome, unilateral compression of the median nerve or ulnar nerve of the limb, or the nerve itself caused by damage to the limbs of the numbness, the main feature is to feel the fingers, especially the anterior wall muscle swelling, swelling and pain, and the fingers will have a sense of inflexibility, superficial B-scans can be done. A superficial ultrasound can clearly show that the median nerve or optic nerve is compressed and the nerve itself is swollen. In this case, it can be diagnosed as carpal tunnel syndrome, which requires local treatment to improve microcirculation, and in severe cases, incision and decompression treatment can be done, which can achieve better results. Unilateral limb or index finger numbness is mainly considered to be peripheral nerve injury, but also pay attention to observation, can not completely exclude central injury, that is, cerebral infarction may be, once the progress of the disease, or the need to consult a doctor as soon as possible.