Curved toes can be caused by congenital developmental abnormalities, trauma, bunion, rheumatoid arthritis, tenosynovitis of the toes and other causes. 1. Congenital developmental abnormality: If the toes are curved at birth, this is a congenital developmental abnormality. 2. Trauma: When the toes are hit or knocked, it will easily lead to injury of toe tendons, fracture or deformation of bones and joints, resulting in bent toes. 3. Bunion: If the shoes you wear are too narrow, your toes cannot be straightened, which in the long run may lead to deformation of the toe joints, resulting in a bunion, which causes the symptoms of bent toes. 4. Rheumatoid arthritis: Rheumatoid arthritis is an autoimmune disease, which can lead to destruction of articular cartilage and bone, and deformity of the toe joints, resulting in curved toes. 5. Toe tenosynovitis: Toe tenosynovitis is mainly manifested as pain and pressure pain around the tendon, and with the aggravation of the disease, the symptom of toe bending may also occur. When toe bending occurs, patients should go to the hospital immediately, after clarifying the cause of the disease under the guidance of the doctor to standardize the treatment.