There is a 90-year-old woman in good health, life can basically take care of themselves, although some arrhythmia (irregular heartbeat rhythm), did not pay too much attention. One day suddenly left lower limb pain, and numbness, cold, in a number of hospitals for treatment, diagnosis is not clear, treatment is not prescription, left lower limb gradually purple, cold, 3 days after the onset of the onset of a referral to the clinic, the emergency surgery, take out the thrombus of about 50 centimeters, hospitalized for 10 days to be cured and discharged. The old lady suffered from acute arterial embolism. Arterial embolism refers to a disease in which an embolus is dislodged from the heart or proximal arterial wall, or enters the artery from outside and is swept to the distal side by blood flow, blocking the arterial blood flow and leading to severe ischemia or even necrosis of the corresponding limb. The embolus of atheroembolism can be composed of thrombus, atherosclerotic plaque, bacterial fibrin clot, air, tumor tissue, foreign objects (e.g., shrapnel), broken guidewire, catheter, amniotic fluid, and fat, etc., but left atrial thrombus is the most common. The disease is acute and life-threatening, so early diagnosis and proper treatment are essential. Generally speaking, if the onset of 12 hours or less can be timely treatment, more than 95% can save the limb; if the onset of 24 hours or less can be timely treatment, more than 80% can save the limb. More than 24 hours there are some patients will inevitably occur necrosis and have to amputate. Some patients with extensive necrosis of the limb to produce a large number of toxins, severe pain stimulation coupled with the original poor physical condition, will be life-threatening, about 20% of the patients died as a result. Arterial embolism of the limb is often characterized by the so-called “5P” sign (the first letter of the English word of the five main symptoms are P): pain, pulseless, pallor, numbness and dyskinesia. The clinical diagnosis of this disease is not difficult, as long as the thought of this disease, without the use of any auxiliary examination, most patients can be clearly diagnosed. If the sudden onset of pain in the limb, accompanied by numbness, coldness, dyskinesia, pallor or bruising of the skin, the first consideration is acute limb arterial embolism. If the diagnosis can be made early, surgical removal of the embolus has a good therapeutic effect. The old lady mentioned earlier is a good example.