Having established intravenous access, standard anaesthetic monitoring will be applied. Sedation with midazolam will be administered as clinically indicated (to a maximum of 3 mg). The operative arm will be abducted and externally rotated with elbow flexed at 90 degrees. Under strict aseptic condition, ultrasound guided axillary brachial plexus block will be performed. Having identified musculocutaneous, median, radial and ulnar nerves, a 50mm 22-gauge ultrauplex short bevel insulated needle will be used with in-plane approach to block each nerve. 20 mL of Lidocaine 2% with epinephrine and 2ml of 0.9% Nacl(group 1) or clonidine 1µg/kg in 2 ml of 0.9% Nacl(group 2) will be divided equally among the 4 nerves. All blocks will be performed by single operator experienced in the ultrasound peripheral nerve blocks.