“…It is well known that RLN is generally divided into two main bundles before enter ing the larynx and that the posterior branch combining with a branch of SLNI composes Galen's anastomosis [Dilworth, 1921;Lemere, 1932a, b;Armstrong and Hinton, 1951;Bowden, 1955;Harrison, 1981]. The present study shows that the posterior branch contains many noradrenergic nerve fibers, though the anterior branch contains only a few.…”