Normal ventilatory movement of the right hemidiaphragm studied by ultrasonography and pneumotachography.

The ventilatory movement of the right dome of the diaphragm was studied over the range of the inspiratory capacity in 50 healthy adults in the supine position using simultaneous ultrasonography and pneumotachography. Regional differences were found in movement of the hemidiaphragm; there was greater movement of the middle and posterior thirds of the diaphragm than of the anterior third. A significant positive correlation was found between body weight and amount of diaphragm movement. An apparently greater degree of movement of the diaphragm was found in males than females; this may be related to weight. About 64% of diaphragm movement has occurred by the time midinspiratory capacity is reached. These data may help to define normal movement and also to differentiate abnormal from normal diaphragm movement.