Diaphragm excursion,diaphragm thickness,and diaphragmatic thickening fraction are three indicators for evaluating the two hemidiaphragms by ultrasound.Diaphragm ultrasound has been widely applied in clinical practice including anesthesia management.It can help to diagnose postoperative residual curarisation and identify patients at a high risk of suffering from postoperative pulmonary complications.It can serve to recognize patients with diaphragm paralysis due to surgical or anesthetic factors as early as possible.Moreover,diaphragm ultrasound plays a role in preoperative pulmonary function assessment for special sufferers with chronic obstructive pulmonary disease,adolescent idiopathic scoliosis,or neuromuscular disease.Apart from these,diaphragm ultrasound can give anesthesiologists and colleagues in intensive care unit an important clue for extubation and weaning from mechanical ventilation of patients.