[Reconstruction for brachial injury by the accessory nerve--anatomy of the accessory nerve and its innervation of the trapezius--Japan].

At present reconstruction of not only elbow function, but also wrist and fingers function is possible for totally paralysed root avulsion type of brachial plexus injuries by means of multiple nerve transfers and free muscle transplantation. Although denervation of the trapezius muscle may be a problem, the accessory nerve is used as the donor nerve for reconstruction. Forty-seven cadaver dissections were performed to determine the innervation of the trapezius. In 98% of the regions, branches of the accessory nerve or the cervical nerves were found to be directly innervated with the accessory nerve in the posterior triangle of the neck without anastomosis. This study came to the conclusion that it was possible to use the accessory nerve as the donor nerve without paralysis of the upper part of the trapezius, if the accessory nerve was used at an adequate point. Since the course of the accessory nerve is similar to one of the cervical nerve in the posterior triangle of the neck, it is difficult to distinguish them. The layer of the course and the great auricular nerve at the posterior margin of the sternocleidomastoid are reference points of the accessory nerve and the cervical nerves.