Background: The nasolabial angle is defined as the angle between the line drawn through the midpoint of the nostril aperture and a line drawn perpendicular to the Frankfurt horizontal while intersecting subnasale. An arbitrary range of 90 to 120 degrees for the nasolabial angle is usually stated in the literature. The purpose of this study was to objectively define the ideal nasolabial angle.
Methods: Life-sized, lateral photographs of 10 men and 10 women who had undergone rhinoplasty performed by the senior surgeon were selected. The photographs were electronically altered to change the nasolabial angle by 4 degrees. For men and women, these angles were 90, 94, 98, 102, 106, and 110 degrees. Sixteen raters, including plastic surgery attending staff, residents, and office staff, selected their most aesthetically pleasing nasolabial angle.
Results: Data analysis was done using the distribution of means of the first preference nasolabial angle values based on all 16 raters. The mean angle for ideal male nasolabial angle was 95.96 degrees ± 2.57 degrees (mean ± SD). The mean angle for women was 97.7 ± 2.32 degrees. Based on these standard deviations, the ideal nasolabial angle would be 93.4 to 98.5 degrees for men and 95.5 to 100.1 degrees for women.
Conclusions: The authors' results indicate a much closer range of nasolabial angle between men and women than previously reported in the literature. This study is the first of its type to objectively define the ideal aesthetic nasolabial angle. In addition, the ideal nasolabial angle for women was found to be less obtuse than previously thought.