Special Sensory Innervation of the Human Tongue

¹ Mayo Graduate School of Medicine, Section of Dermatology and Section of Dentistry, Mayo Clinic, Rochester, Minnesota

Specimens (obtained during oral and pharyngeal operations) from various regions of 32 normal human tongues were studied by silver-staining and cholinesterase techniques. The greatest density of special sensory innervation in the tongue is seen in the circumvallate-papillae area. There is no quantitative difference between males and females, although there is a discernible decrease in taste innervation after the sixth decade of life in both sexes. Fungiform papillae possess fewer taste buds than do circumvallate papillae, and filiform papillae possess no taste buds. Cholinesterase, commonly found in nerve endings, is not seen in taste buds, giving support to the concept that taste buds are not neurogenic structures. The submucosal nerve network of the tongue (and other oral mucous membranes) is analogous to the subepidermal nerve network in the skin. This network is most dense in the circumvallate-papillae area and decreases toward the anterior portion of the tongue.

The neural compositions of the fungiform and circumvallate papillae are similar, that of the latter being more extensive and associated with a greater number of taste buds. Filiform papillae possess rather sparse innervation. Fibrils from each nerve fiber begin to branch about 50 µ from the base of the taste bud and project a short distance into the bud. No perigemmal or intergemmal innervation was found.