Lingual distribution of the human glossopharyngeal nerve.
CONCLUSIONS
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.


OBJECTIVE
To assess the anatomical distribution of CN IX on the lingual dorsum.


METHODS
Three human cadaver tongues were microdissected following staining with Sihler's stain, a procedure that renders most of the tongue tissue translucent while counterstaining nerves. CN IX nerve branches were visually tracked within the tongue's dorsum.


RESULTS
Branches of CN IX were observed that extended anteriorly beyond the sulcus terminalis and the circumvallate papillae, with extensions occurring along the lateral lingual margin anterior to the foliate papillae. Anastomoses were identified between CN IX and the lingual nerve, raising the possibility of functional interactions between CN V and CN IX.
Doty
Richard L
RL
Smell & Taste Center, Department of Otorhinolaryngology: Head and Neck Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA. doty@mail.med.upenn.edu
Cummins
Daniel M
DM
Shibanova
Anna
A
Sanders
Ira
I
Mu
Liancai
L
D000368:Aged; D005260:Female; D005930:Glossopharyngeal Nerve / Q000033:anatomy & histology*; D006801:Humans; D008036:Lingual Nerve / Q000033:anatomy & histology; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D013649:Taste / Q000502:physiology*; D013650:Taste Buds / Q000033:anatomy & histology; D014059:Tongue / Q000294:innervation*