Adult brachial plexus injury (BPI) is a closed injury. It usually involves a plexus of nerves formed by a number of roots, spinal nerves, trunks, cords, and numerous terminal branches, in a complicated fashion. Successful results in the management of adult BPI are based on the knowledge of anatomic arrangement, pathophysiology considerations, preoperative evaluation and diagnosis, surgical technique, postoperative management, rehabilitation and regular patient follow-up, surgical treatment of sequelae deformities, and factors influencing its results. This article deals with traumatic lesions of the brachial plexus in adults, and focuses on controversial questions and philosophy of treatment of adult BPI.