In vivo assessment of diaphragm contraction by ultrasound in normal subjects.

BACKGROUND--Ultrasound allows observation of the thickness of the diaphragm in the zone of apposition in vivo during relaxation and maximum inspiratory efforts. METHODS--Changes of diaphragm thickness were studied by B mode (two dimensional) ultrasound in 13 healthy men aged 29-54 years in the seated position. A high resolution 7.5 MHz ultrasound transducer was held perpendicular to the chest wall in the line of a right intercostal space between...