The enlargement of the bones at the fingertip joints is seen in two cases: 1. In the course of adolescent development, if there is a contusion of the fingers, such as in basketball, accidental falls resulting in significant damage to the joints of the fingers, it can lead to damage to the epiphysis at the fingertip joint location, which can affect the normal development of the bones and lead to enlargement and deformity of the joint location. 2. Due to rheumatoid arthritis. Rheumatoid arthritis is mainly manifested in symmetrical small joint pain, deformity and enlargement of both hands, which is due to the formation of local sterile inflammatory lesions in rheumatoid, and the calcium salts of inflammatory metabolites in the process of gradual deposition, forming local calcification and hyperplasia, which will appear enlarged and deformed after a long time.