The common name for pestle and mortar nail is flattening of the nail plate, the edges of the nail are raised, the middle part is thin, the nail becomes brittle and cracks easily, the surface of the nail is dry and sometimes streaks appear. In severe cases of pestle and mortar, the center of the nail may become depressed. There are many causes of pestle finger, commonly due to infectious myocarditis, rheumatic heart disease, etc. Respiratory diseases such as bronchiectasis, chronic lung abscess, emphysema, etc., cause pestle finger due to insufficient oxygenation of venous blood and chronic hypoxia of tissues in the patient’s body, and other diseases such as iron deficiency anemia can cause hypoxia in the body, or insufficient oxygen supply leading to pestle finger. Sometimes it may be closely related to genetics as well, or it may be related to specific occupations, such as people who are exposed to strong acids, bases, and petroleum, and may also develop pestle fingers. If you have pestle fingers, you should go to the hospital promptly with relevant tests, such as trace elements, thyroid function, cardiac ultrasound, and routine blood tests, to determine the specific cause of pestle fingers and to carry out targeted treatment.