filliformpapillae

Filiform papillae, sometimes spelled filliform papillae, are the most numerous type of lingual papillae on the dorsum of the tongue in humans and many other mammals. They are slender, conical or thread-like projections of the stratified squamous epithelium and are heavily keratinized. Unlike other papillae, filiform papillae do not contain taste buds.

Filiform papillae are densely arranged in rows across much of the anterior two-thirds of the tongue, giving the tongue its characteristic rough texture. Their surface is highly keratinized, contributing to mechanical friction with food and aiding in moving material within the mouth. They are thought to provide tactile sensation and assist in oral cleaning rather than gustation.

In development, filiform papillae arise from the tongue epithelium and acquire keratinization as the individual matures. Histologically, they are slender cores of connective tissue enveloped by stratified squamous epithelium with a thick keratin layer.

Clinically, elongation or hypertrophy of filiform papillae can occur, most notably in hairy tongue (lingua villosa), where the papillae become elongated and discolored, producing a hairy appearance. Contributing factors include poor oral hygiene, tobacco use, certain medications, antibiotics, and xerostomia. These changes are typically benign and reversible with improved hygiene and removal of risk factors.