There are many reasons for the swelling of the right ankle, which need to be analyzed on a case-by-case basis: if the patient has trauma, it is necessary to exclude fractures, soft tissue sprains and some traumas that cause arthritis, etc. If the swelling is due to infection, it is necessary to exclude the presence of bacteria, tuberculosis, etc., which cause synovitis of the ankle joint. Chronic arthritis, such as rheumatoid or gouty arthritis, is also a cause of ankle swelling. Rare cases, such as hemophilic arthritis and allergic purpura, can also cause blood accumulation in the ankle joint, leading to swelling. In addition, tenosynovitis and tendon sheath cysts, can also manifest as swelling of the ankle joint. A series of causes can be identified and judged with the help of medical history, physical examination, imaging and laboratory tests for leukocytes, neutrophils and C-reactive protein.