In clinical practice, we often encounter patients who come to the clinic with numbness in the extremities. Although numbness in the extremities is manifested in the hands, in fact, it is often a signal of systemic diseases, or even a precursor of some critical illnesses, which must be paid great attention to. So clinically numbness of the extremities is common in which diseases? First of all, it may be a precursor to a stroke. Cerebral hemorrhage, commonly known as stroke, is a common disease among the elderly, more men than women, and most cases of stroke are caused by hypertensive disease. If sudden numbness of the limbs excludes other causes or is accompanied by hemianesthesia, you should be alert and seek medical attention in a timely manner. Although some of the numbness of the limbs accompanied by hemianesthesia relieves itself after a few minutes, it should not be taken lightly and there is still a possibility that a stroke may occur after a few hours or a day or two. Therefore, friends with hypertension should pay close attention to this symptom, which is likely to be the precursor of a stroke. Secondly it may be a sign of cervical spondylosis. There are many people who develop numbness in the upper limbs, often caused by cervical spondylosis, commonly between the fifth and sixth and sixth and seventh cervical vertebrae, which compress the sixth and seventh cervical nerve roots. Acute cases have raised neck and shoulder pain that radiates to the radial side of one upper extremity (both arms are down, palms forward, and the side against the body is the radial side). When the sixth cervical nerve root is compressed, it often causes numbness in the thumb and index finger, and if the seventh cervical nerve root is compressed, numbness in the index finger and middle finger occurs. Usually, the symptoms can be reduced or disappeared by traction, massage or physiotherapy treatment. Again it may be a symptom of polyneuritis. The numbness in the limbs that occurs in this condition is often a symmetrical glove and sock-like distribution of the fingers and toes. The causes of polyneuritis are particularly complex and are usually caused by infection, metal or chemical poisoning, malnutrition, metabolic or endocrine disorders, connective tissue diseases, allergic diseases, cancer, genetics, and other factors. In addition, clinical conditions such as myelopathy or hypoparathyroidism can also present with limb numbness and need to be differentiated in conjunction with other conditions.