Any of the the series of transverse folds (ridges) of the mucosa located on the anterior third part of the secondary (hard) palate of most mammalian species.
Comment:
[structure-note] "rugae are present on each side of the median palatal raphe and behind the incisive papillae, but their number and arrangement are species specific; together with the teeth and the tongue, rugae take part in mastication by helping to sense, hold and mash the food; rugae harbor various types of intraepithelial sensory structures (such as Merckel cells, corpuscular endings and free nerve endings), and play a sensory role when the food is pressed by the tongue against the hard palate[MP]"