Scarlata S, et al. - In a sample of one-hundred healthy volunteers, researchers prospectively evaluated the supine diaphragmatic motion amplitude, intra- and inter-observer agreement, and anthropometric correlates of diaphragm motion variability, measured through M-mode ultrasonography. The findings from the present study suggested that diaphragm excursion measurements using the M-mode technique were accurate and could be reproduced also when obtained in recumbent patients. Sex and height were the main predictors of diaphragmatic motion, which should be considered to design a specifically tailored study and to develop normality reference equations after adjustments.