**10. Implementation of the blockade**

Having identified the brachial plexus in the interscalene space, the needle is inserted lateral to the transducer (flat) and with a local anesthetic bolus (remember the plexus is located about 1 cm from the skin), the needle is advanced while directly visualization the plane with the transducer until it enters the interscalene groove and is located adjacent to a nerve root. It is preferable to situate the needle at the deepest roots so that when we start to infuse the local anesthetic, it pushes us toward superficial plexus, improving the success rate. After gentle aspiration, we proceed to inject the local anesthetic, confirming the spread of local anesthetic into the interscalene groove by direct visualisation.
