RÉSUMÉ
The brachial plexus block is a valuable method of providing anesthesia for the surgery of forearm and hand. Common technique for brachial plexus block include axillary, supraclaviculer, and interscalene approaches. The supraclavicular brachial plexus block offers adventages, ie, high success rate, rapid onset of action and relatively complete block over axillary and interscalene approach, but may be associated with pneumothorax. We marked the P point which was placed on the upper margin of clavicle that crossed the first rib on the chest PA film and marked on the skin of the patient and inserted 23G scalp needle at that point to the first rib. We performed this modified technique of supraclavicular brachial plexus block using chest PA film in 20 patients and there was no incidence of pneumothorax after this block but general anesthesia was sdministered in one case because of incomplete block. We recommend that this modified technique guided by chest PA film for supraclavicular block is simple, reliable and may reduce the incidence of pneumothorax and to increase the success rate in difficult case such as patient with extremely obesity.