Restoration of elbow flexion is a major objective in the treatment of brachial plexus palsies affecting the upper roots. The “Ulnar-Biceps Median-Brachialis” (the so-called UBMB) double nerve transfer described by Oberlin became a standard procedure in C5-C6 and C5-C6-C7 injuries. Motor fasciculi of the ulnar and median nerves dedicated to wrist flexors are transferred onto branches from the musculocutaneous nerve, aiming at the biceps and the brachialis muscles, respectively. Perioperative nerve stimulation is essential for choosing the appropriate donor branches, in order to spare the priority functions of the hand. On the other hand, lesions of the posterior cord of the brachial plexus are rare. The symptoms are usually described as palsy of the deltoid and triceps brachii muscles and of the extensor muscles of the wrist, thumb, and fingers. In the absence of spontaneous recovery, surgery is Indicated. For elbow extension restoration, our preferred technique is the transfer of one fascicule of the ulnar nerve to a nerve branch of the triceps brachii (medial or lateral head). This procedure is easier than the transfer of intercostal nerves and spares them to perform reinnervation of deltoid muscle.