Some of the unevenness of the right thumb nail is caused by congenital factors. Excluding congenital factors, the main consideration for unevenness in the later stage is malnutrition, infection or trauma. 1. Congenital factors: most of the nails caused by congenital factors are hereditary and will not cause any discomfort. 2. Malnutrition: Prolonged anorexia, picky eating, resulting in a lack of calcium and other trace elements, may cause related symptoms, mainly calcium deficiency will affect the normal growth of nails. 3. Infection: the most important is fungal infection, especially after the appearance of gray nails, it will cause the nails to become brittle, thick, uneven. 4. Trauma: Trauma causes localized damage to the nail bed, and in the process of repair, it can also cause uneven nails. There are other reasons for uneven nails, so you need to consult a doctor for observation and standardized treatment after determining the specific condition.