Diaphragmatic ultrasound. Curved array transducer (1) position for scanning the diaphragm in the midclavicular, right subcostal margin using the liver as an acoustic window, and linear array transducer (2) on the left in the midaxillary line at the level of ribs eight to nine. Image reproduced with permission from Maria Fernanda Rojas Gomez and Ultrasound for Regional Anesthesia (USRA; http://www.usra.ca).