Mortar and pestle fingers can be seen in various diseases and causes of hypoxia. Pestle fingers are characterized by enlarged and mallet-shaped ends of the fingers and toes, with a marked widening of the end knuckles and a bulging nail from root to end. Congenital diseases, such as congenital heart disease causing hypoxia, including precordial heart or wind heart, become pestle-shaped fingers after a long period of hypoxia. Respiratory diseases, such as thoracic deformity, chronic obstructive pulmonary disease, bronchiectasis, lung cancer, and pulmonary fibrosis, may also be associated with a longer period of hypoxia, and some people may have pestle-like fingers.