Enlargement of knuckles can be seen in physiological enlargement and pathological enlargement. The common causes of physiological enlargement are genetic factors, more use, etc. The common causes of pathological enlargement are trauma, tenosynovitis and arthritis. 1. It may be due to genetic factors, family members have large knuckles, resulting in the inheritance of large knuckles to themselves, so the knuckles are large. 2. It may be due to the frequent use of finger joints in daily life and work, and more activities of the finger joints, resulting in the appearance of enlarged finger joints. 3. Finger joint tendinitis may be caused by prolonged overwork or cold stimulation of the finger joints, which results in aseptic inflammation of the finger joints and swelling of the finger joints. 4. Rheumatoid or rheumatoid arthritis may be present, which may lead to tissue degeneration at the knuckles, causing swelling and enlargement. There may be other reasons for enlarged knuckles. If there is swelling, pain and other discomforts, it is recommended to consult a doctor in time and give standardized treatment under the guidance of the doctor.