Longitudinal ridge is a longitudinal stripe of varying depths on the nail bed along the long axis of the nail, and is more common on the nails of the thumb and index finger. The cause of the longitudinal ridge is uncertain and may be due to nutritional deficiencies, chronic sleep deprivation, fungal infections, thyroid disorders, and chemical stimuli such as benzene. It appears as a longitudinal stripe of varying depths along the long axis of the nail bed, often accompanied by rupture and separation of the nail bed. Treatment is usually recommended to increase the intake of calcium nutrients, discontinue chemical stimulation, improve sleep, regular anti-infection treatment, and actively treat the primary disease. It is recommended to go to the hospital to find out the cause of the longitudinal ridge of the nail and give targeted treatment if necessary.