Palatal taste buds in man: topographical arrangement in islands of keratinized epithelium.

In an attempt to find and reconstruct the exact anatomical correlate of taste sensitivity in the human soft palate, a novel approach was used to examine the mucosal surface in conjunction with serial tissue sectioning. Six human subjects, 15 to 29 years of age, 3 females and 3 males, served to take precision impressions of the hard and the anterior soft palate, using non-commercial trays and a self-curing resin. From these impressions, replicas were cast in Epon and subsequently sputter-coated with gold and examined in a scanning electron microscope. In addition, one biopsy was taken from one of the volunteers, in an area including taste bud-suspicious elements. It was found that the anterior soft palate mucosa included 10 to 30, oval to round, site-exotic islands, about 0.2-0.6 mm in diameter, which were covered by a thin, keratinizing stratified squamous epithelium. These islands occurred mainly in an area located in the central part of the soft palate, immediately posterior to the hard/soft palate boundary. The keratinizing epithelium of such islands carried four to seven taste buds which were lacking elsewhere. These islands were formed by a large, mushroom-like connective tissue papilla penetrating most of the site-specific mucosal epithelium, with its cover of keratinizing epithelium, forming sharp external and internal cell-to-cell borderlines with the surrounding, non-keratinizing stratified squamous epithelium. These findings are discussed in relation to induction phenomena necessary to form such islands, and to the variable taste sensitivity detected clinically in this region.