A three-dimensional quantitative analysis of lips in normal young adults.

OBJECTIVE To supply information about (1) sex-related dimensions (linear distances and ratios, vermilion area, volume) of normal adult lips, (2) presence of sexual dimorphism, and (3) correlations between anthropometric characteristics of the lip and nose. METHODS The three-dimensional coordinates of soft tissue landmarks on the lips and nose were obtained using an optoelectronic instrument in 90 healthy young adult women and 90 healthy young adult men. From the landmarks, several linear distances (mouth width, total vermilion height, nose height, anatomic nose width, total lip height, upper lip height), the ratio of vermilion height to mouth width, and some areas (vermilion of the upper lip, vermilion of the lower lip, total vermilion) and volumes (upper lip volume, lower lip volume, total lip volume) were calculated. Linear correlation analyses between pairs of variables were also conducted within each sex. RESULTS All lip dimensions (distances, areas, and volumes) were significantly larger in men than in women (p<.005), but no sex differences were found in the vermilion height to mouth width ratio. Overall, mouth and nose dimensions were not significantly correlated, with the exceptions of the upper and lower lip volumes in both sexes and of the mouth and nose widths in the female sample, in which a modest part of the variance in one measurement could be explained by the other. CONCLUSION The dimensions of the mouth and the nose did not seem to be strictly related. Data collected in the present investigation could represent a database for the quantitative description of human lip morphology in adult subjects.