The ankle joint inexplicably appears swollen and painful for the patient, that is, without having been traumatized. The common causes of this condition are the following: 1, ankle synovitis, due to to to the synovial membrane appears aseptic inflammation, resulting in the synovial membrane of the hyperplasia, hypertrophy, vascular hyperplasia, inflammatory exudation increased, appearing joint cavity fluid, joint local swelling, local tissue tension increased, produce pain, and then due to the stimulation of inflammation, will also be to appear painful symptoms. 2, seen in gouty arthritis, especially Seen in middle-aged obese men, who usually prefer to eat meat and drink alcohol, resulting in increased blood uric acid. Under the stimulation of unfavorable factors, such as cold, injury, etc., resulting in uric acid crystals, deposited around the joints, irritating the symptoms of swelling and pain, especially the typical local symptoms of redness, swelling, heat and pain. 3, can be seen in local poor blood circulation, including varicose veins, vasculitis, etc. Due to poor local blood circulation, there will be an accumulation of tissue metabolites, local tissue ischemia and hypoxia, resulting in corresponding congestion, edema and inflammatory reactions, which will also lead to local symptoms of swelling and pain.