In-plane needle image

Examples of in-plane technique for axillary block. Panel A shows a partial (incomplete) lineup, meaning that although some of the needle shaft is imaged, the needle tip does not lie within the plane of imaging. This is one of the most common problems during interventional ultrasound for regional anesthesia. Panel B shows a complete lineup, with the needle bevel identified (arrow). Note incidentally that there is some difference in acoustic shadowing from the neurovascular bundle along the needle shaft.