In the absence of data from previous study using 20 ml of lidocaine with epinephrine for ultrasound guided axillary brachial plexus block. Sample size was calculated based on from our pilot study of 8 patients. We found mean onset of block of 11.25 (SD, 2.3) mins. The minimum sample size required to have an 80% probability of detecting a 30% decrease in onset time (level of significance 0.05) will be 9 patients per group using an unpaired student's t test. Recruited 10 per group