The surgical anatomy of the spinal accessory nerve and the internal branch of the superior laryngeal nerve.

Injury to the spinal accessory nerve may occur during conservation neck dissection. In supraglottic laryngectomy preservation of the internal branch of the superior laryngeal nerve has largely been ignored. Cadaver dissection and diagrams are used to review the surgical anatomy of these two structures. Particularly important are the relationship of the spinal accessory nerve to the sternocleidomastoid muscle, its interaction with the cervical plexus, and its superficial path inferiorly. Landmarks for the identification of the internal branch of the superior laryngeal nerve are indicated, and technique for preservation is described. An intact accessory nerve can be efficiently preserved thereby eliminating the shoulder syndrome. Significant sparing of the internal branch of the superior laryngeal nerve can be routinely accomplished as an aid in minimizing postoperative aspiration.