Nail curvature may be caused by lack of micronutrients, lack of oxygen, pestle finger, gray nails, etc. It may also be caused by hereditary factors. 1. Lack of trace elements: When the body lacks calcium, zinc and other trace elements, it may cause abnormal nail development and the phenomenon of too large a curvature of the nails. 2. Mortar and pestle finger caused by lack of oxygen: chronic obstructive pulmonary disease, emphysema and other diseases can lead to lack of oxygen in the body, which can lead to mortar and pestle finger, which can be manifested as too large a curvature of the nails. 3. Gray nail: due to fungal infection of the nail, it can cause the middle of the nail to arch up, which can appear as too much curvature of the nail. 4. Genetic factors: some people are also caused by genetic factors, do not need to be too nervous. It is recommended to go to the hospital in time to clarify the cause of the disease and carry out standardized treatment under the guidance of the doctor.