Causes of finger joints thicker reasons, common causes are finger synovitis, rheumatoid arthritis, stenosing tenosynovitis, etc., in addition, the big bone joints disease, local strain or post-traumatic hyperplasia and other factors, can also lead to this phenomenon. 1. Synovitis of the fingers: it can be caused by overwork or trauma, infection, tuberculosis and other factors in life, the main symptoms are joint swelling, pain, activity limitation and so on. In the course of the disease is relatively long, can produce local osteophytes, soft tissue swelling and other lesions, and lead to finger joints thick. 2. Rheumatoid arthritis: Rheumatoid arthritis may be associated with autoimmunity, heredity, infection, smoking and other factors. Rheumatoid arthritis usually starts from the proximal interphalangeal joints, metacarpophalangeal joints, wrists and other small joints, with symptoms such as morning stiffness, swelling, pain and so on, which is manifested as enlarged finger joints. 3. Stenosing tenosynovitis: it occurs in people who need to make repeated extension, flexion, grip and pinch movements, the typical symptoms are usually pain and activity disorder, and it can also cause swelling of the finger tendon sheaths, which is manifested as large finger joints. 4. Osteoarthritis: the cause of the disease is not clear, may be related to environmental factors or infectious factors. 5. Localized strain: mostly caused by overwork in the local area, and the hand joints will gradually become thicker if they are overworked regularly. 6. Post-traumatic hyperplasia: mostly related to infection, trauma, or repeated stimulation of foreign objects, which can lead to thickening of the knuckles. It is recommended to go to the hospital in time to clarify the cause of the problem and to have professional treatment under the guidance of the doctor.