Patchy analgesia and incomplete motor blockade sometimes occur during surgery of the upper limb under axillary brachial plexus blockade. To avoid these problems, we sought an alternative approach to the brachial plexus to guarantee reliable anaesthesia. Based on anatomic studies, we undertook a prospective clinical study with 175 patients. METHODS. One hundred seventy-five patients undergoing surgery of the upper limb were anaesthetised using the new technique, based on the results of the anatomic study. We divided the distance between the fossa jugularis and the ventral process of the acromium into two equal parts. An exactly vertical puncture was made using an electrical stimulation cannula and nerve stimulator set at 1.0 mA until muscle contractions were noted in the area to be operated. The current was then progressively reduced to at least 0.3 mA; 400 mg Prilocaine 1% and 50 mg bupivacaine 0.5% were applied in a single injection. RESULTS. Operability was achieved in 94.8% of patients within an average time of 13.5 min after injection (minimum 5 min, maximum 30 min). The tourniquet was tolerated in all cases. For sedation or analgesia, 32.5% required no drugs, 57.1% received low doses of hypnotics (< 5 mg midazolam) as desired, and 5.2% required systemic analgesia due to patchy anaesthesia. In 5.2% of cases the block was insufficient and general anaesthesia was administered. Except in these cases, complete blockades were found after surgery. Postoperative analgesia lasted for 3 to 20 h with an average of 8 h. All patients were satisfied with the anaesthesia and would choose this method another time. Venous puncture occurred in 18 cases without significant problems. In 12 cases we observed Horner's syndrome. No arterial or pleural injury was observed. CONCLUSIONS. Infraclavicular vertical brachial plexus blockade represents a highly successful method compared to other common techniques. Tolerance of the upper arm tourniquet for even longer periods also demonstrates the effective anaesthesia. Other important advantages include a very rapid onset of complete neural blockade and long-lasting postoperative analgesia. The method had low risks and high acceptance by both patients and anaesthesists.