Two fingernail caps on the little toes may be a split-flap appearance, also known as a flap nail. It is mainly considered to be related to autosomal dominant inheritance and is not a pathological manifestation. It is also possible that external forces may be responsible for the damage to the nail to form a split-valve nail. 1. Genetic factors: parents or grandparents in the family, the appearance of petaloid nail. The children of those parents or grandparents may also develop this condition. There are also some people who had normal nails as children and slowly develop this condition as they grow older. Hereditary factors lead to flap nails, is a normal performance is not a disease, generally do not need treatment. 2. External force: localized by long-term friction or external force, resulting in nail damage, can appear divided flap nail. It is recommended to take good care of the local area to avoid further trauma and increase the chance of infection. With the passage of time, it can gradually improve. The appearance of flap nails in nails, if there is no any uncomfortable symptoms, it is considered to be related to heredity, and close observation is recommended. If it is caused by external force, there may be obvious redness, swelling and pain, you can use medication under the guidance of the doctor, which is conducive to the subsidence of inflammation.