has part has part characteristic of has modifier Abnormal lower lip morphology Thin vermilion border Thin lower lip vermilion Normal values for the height of the vermilion are available [Farkas, 1981] but measurements are not commonly used. Most clinicians determine this feature subjectively. The height of the vermilion of the lower lip varies considerably among ethnic groups, and the vermilion should be compared to a population of same ethnic background. If the lower lip vermilion is thin, the inferior border of the vermilion is less curved, and on a profile view, the lower lip vermilion is less convex than usual. abnormal decreased thickness lower lip