Variant Patterns of Palatal Rugae Induced by Chemicals in Mouse Fetuses

The oral surface of the mouse palate has eight or nine pairs of transverse ridges, or rugae. We have reported that various teratogens induce abnormal patterns of palatal rugae in mice. In the present note, we show examples of palatal ruga anomalies induced by several teratogens in mouse fetuses near term. Defined variant patterns are supernumerary, division, lateral or medial bifurcation, short, maldirection, cross, modified cross, lateral or medial fusion, lateral or medial bifurcation, median fusion, median division, and numerical reduction. In some cases naming of observed variants may be difficult, but differential diagnosis between variations in the “normal” range and “anomalous” variants seems rather easy.