There are two possible causes of painful symptoms in the fourth toe: first, the most common cause is chronic injury, especially in people with a special walking posture. In people who walk with their legs and feet supported by the outside of their bodies, who walk more closely to the inside eight, and whose soles are often rubbed flat on the outside, the outer fourth toe is the toe that is mainly under pressure. Once the regular walking time is too long, or often excessive exercise, it will gradually damage the joints of the fourth toe, and the ligaments and tendons on both sides of the toe will also be damaged, and the accumulation of too much subtle damage will result in too much exudation, leading to local pain symptoms. Secondly, if people are older, their body functions degenerate more obviously, and the cartilage of the body joints will undergo degenerative calcification, which will cause the joints to lose their functions, and stimulation such as walking activities will cause inflammation of the joints and cause pain.