High-resolution sonography of the recurrent laryngeal nerve: anatomic and pathologic considerations.

During sonographic examination of the neck using high-resolution small-parts equipment, the minor neurovascular bundle may be identified in virtually all patients. Postmortem studies in three cadavers demonstrated that this structure is actually the recurrent laryngeal nerve (RLN). Furthermore, findings observed during sonographic examinations of the neck in nine patients with RLN paralysis of unknown origin were reviewed. Compression, displacement, or infiltration of the nerve from thyroid (seven cases) or parathyroid (two cases) nodules were noted, and this allowed the site and cause of the paralysis to be identified.