Lingual distribution of the human glossopharyngeal nerve.

Conclusion: Nineteenth century anatomical descriptions of the anterior distribution of cranial nerve (CN) IX on the dorsal tongue are contrary to current concepts. By employing Sihler's stain, we demonstrated that, in fact, CN IX projects more anteriorly than the posterior third of the tongue. This may explain why some patients whose chorda tympani branch of CN VII has been severed during middle ear surgery continue to have taste function in sectors of the anterior two-thirds of the tongue.