Observations on the Geniculate Ganglion in Adult Human Dissections

Abstract

The geniculate ganglion is of clinical importance because it is the site of the nerve cell bodies for the special sense of taste. Its location has been described in anatomy textbooks as being on the facial nerve at the point in the facial canal where the nerve bends sharply backwards laterally making a right angle. The name “geniculate” is derived from the shape of the ganglion described above. None of the textbooks give a detailed account of the shape of the ganglion or of the ramus that arises in the vicinity of the ganglion and communicates with tympanic nerve and tympanic plexus. We made detailed dissections of the ganglion in Japanese adults and found that the communicating ramus with tympanic nerve and tympanic plexus was usually not a single branch, but several branches that arose in all of the regions described in the literature. The ganglion often had an outer S or sigmoid shape that varied with the number and region of origin of the branches. Regarding the three dissections, we counted neurons in the geniculate ganglion.