ObjectivesM‐mode sonography is a noninvasive method for detection of diaphragmatic excursion and thickness. A few studies have assessed diaphragmatic kinetics in children with diaphragmatic paresis and paralysis, but to our knowledge, no data about normal values in pediatrics are available. The aims of this study were to determine reference values for diaphragmatic excursion and thickness, as evaluated by sonography in healthy infants and children, and identify correlations between them and anthropometric measurements, age, and sex.MethodsA total of 400 healthy participants aged between 1 month and 16 years, divided into 4 equal groups (group 1, 1 month–2 years; group 2, 2–6 years; group 3, 6–12 years); and group 4, 12–16 years) were studied. M‐mode sonography was used to measure the excursion and thickness of the right and left hemidiaphragms (using the liver and spleen as acoustic windows, respectively).ResultsReference values for diaphragmatic excursion and thickness were determined in different age groups of healthy infants and children. There were no significant differences with respect to sex. Significant positive correlations were found between excursion of the right hemidiaphragm and body weight in all age groups (r = 0.52, 0.25, 0.27. and 0.20; P < .001, .013, .011, and .047 for groups 1–4, respectively). We plotted percentile curves for right diaphragmatic excursion against body weight.ConclusionsThis study provides reference values for diaphragmatic excursion and thickness in healthy infants and children. Percentile curves for right diaphragmatic excursion plotted against body weight were plotted.