Anaesthesia for surgeries to the upper extremity commonly is provided using brachial plexus anaesthesia.Various local anaesthetic mixtures can be used to prolong local anaesthesia duration and epinephrine , opioids and dexmedetomidine are frequently used for this purpose. this study was conducted to compare the effects of adding dexmedetomidine to local anaesthetics in the supraclavicular brachial plexus block by using nerve stimulators and ultrasonography guided. dexmedetomidine has also been found the prolong the duration of bupivacaine infraclavicular brachial plexus block.