Fig. 2. A vertical centimeter scale is placed to measure the error associated with each of the three infraclavicular block approaches—midclavicular, mediocaudal to coracoid, and infracoracoid. The approach error was defined as the distance between the plexus midpoint and the actual point on the plexus targeted by a posteriorly directed needle, as recommended by a specific approach. The letters x, y , and z represent the plexus midpoint ideally targeted by the midclavicular, mediocaudad to coracoid, and infracoracoid approaches, respectively. The yellow stripe is at the midclavicle.