Open edges of nails are usually referred to as split nails and separated nails. Consider and history of trauma, malnutrition, fungal infections and other factors. 1. History of trauma: Nails are subjected to external forces, such as smashing, which may lead to separation of the nail from the flesh and upturning of the nail edge. It is recommended to take good local care, keep the area around the wound clean and dry to avoid inducing infection, and go to the hospital to ask the doctor for treatment if necessary. 2. Malnutrition: If there are eating disorders, nutrient absorption disorders or excessive dieting, resulting in severe malnutrition, it will affect the growth of nails, and nails may have open edges, upturned nails, nails and flesh separation and so on. 3. Fungal infection: Fungal infection of the nails can lead to onychomycosis, which may lead to changes in texture, color and character, and the occurrence of nail splitting and nail separation. Nail cracking, nail separation may also have other reasons, it is recommended to do a good job of local care, timely to the dermatology department, combined with the doctor’s advice to standardize the treatment.