ABSTRACT
Figure 15.24). If a nerve stimulator is used, paraesthesia in the elbow or thumb is looked for, or movements of the wrist or fingers occur.
Keeping a finger in this groove, the needle is inserted where the drawn line from the cricoid crosses the interscalene groove. This is often where the external jugular vein crosses the groove, and is at the level of C6. This is shown in Figure 15.27. The needle is introduced at 90° to the skin, and slightly dorsally (Figure 15.28). The sheath is usually entered between 1 and 2.5 cm from the surface and a ‘pop’ can be felt on occasion with a short bevelled needle.
