Fig. 4.

Diaphragmatic excursion. A Placement of ultrasound probe to record diaphragmatic excursion from (left) right hemidiaphragm, and (right) left hemidiaphragm. B Diaphragmatic excursion measurements in M-mode. Diaphragm excursion plotted versus SCPP C during quiet breathing, and D during deep breathing. Black, all recordings; blue, recordings when not attached to ventilator. Red is data from controls without cervical TSCI. Mean ± standard error. Best fit curve (C black, linear r² = 0.00; C blue, linear r² = 0.38; D black, cubic r² = 0.79; D blue, quadratic r² = 0.93). Sample sizes in Additional file 8