The fourth toe bending inward is an abnormal phenomenon, which may be caused by trauma, followed by rheumatoid arthritis, long-term extrusion may also cause this problem. 1. Trauma: If the fourth toe has been fractured, dislocated and other traumatic injuries, and is not treated in time, it may be bent inward. 2. Rheumatoid arthritis: Rheumatoid arthritis can leave the toe joints in a state of sterile inflammation for a long period of time, which may cause damage to the toe joints and show the symptom of inward curvature. In addition to joint bending, it may also be accompanied by redness, swelling, pain and other problems, and early treatment is recommended. 3. Long-term extrusion: If you wear narrow shoes for a long time, your toes will be in a constant state of extrusion, and they will bend inward over time. This situation mostly occurs in the group of women who like to wear high-heeled shoes. If the toes are curved inward, but there is no discomfort, you can leave the condition untreated for the time being. If the condition is already affecting your daily activities, you should seek medical attention without delay.