| Literature DB >> 26180712 |
Yvonne E Kaptein1, John S Kaptein1, Alexander Markarian1.
Abstract
BACKGROUND: During reconstruction or augmentation, it is important to localize the malar complex in a symmetrical and aesthetically pleasing position. Few studies have determined the location of this feature and none related the location to gender, age, or ethnicity. Some of these have attempted to relate the position to the aesthetically pleasing Golden Ratio φ.Entities:
Year: 2015 PMID: 26180712 PMCID: PMC4494481 DOI: 10.1097/GOX.0000000000000383
Source DB: PubMed Journal: Plast Reconstr Surg Glob Open ISSN: 2169-7574
Fig. 1.Predicted location of the malar prominence based on the Golden Ratio. Lines demonstrate localization of the malar prominence based on Golden Ratio relationships to other facial features.[2–4] The position of all lines drawn is those shown in Ricketts.[2–4] Ratio of the height of the malar prominence to that of the lateral canthi: (φ + 0.5)/(φ + 1) ≈ 0.809. The relative height of the malar prominence can alternatively be expressed as φ/2 ≈ 0.809.
Fig. 2.Calculating cheek height to canthus height ratio. Points represent facial landmarks. Lines through canthi and commissures converge at a vanishing point (not shown). Lines are drawn from this point to chin and malar prominence. We define height ratio of malar prominence as ratio of vertical distances a to b. Calculations for the individual are shown as follows: Origin of the coordinate system is at top left. (x,y) coordinates of the right eye canthus are (4.261, 5.039) and of the left eye canthus (6.009, 4.933), right mouth commissure (4.651, 6.616), left mouth commissure (5.430, 6.593), base of chin (5.182, 7.548), and malar prominence at the edge of the face (4.036, 5.538). Thus, the line running through the eye canthi is defined by: y = (4.933 − 5.039)/(6.009 − 4.261) × (x − 4.261) + 5.039. This can be simplified to y = −0.061 × x + 5.297. Specifically, at the x-coordinate of the malar prominence (4.036), the y-coordinate (ie, top of arrow “b”) is found to be 5.053. The y-coordinate of the top of arrow “a” is directly observed to be at 5.538. Similarly, the line running through the commissures of the mouth is defined by: y = (6.593 − 6.616)/(5.430 − 4.651) × (x − 4.651) + 6.616, which can be simplified to y = −0.030 × x + 6.753. The lines through the eye canthi and the mouth commissures meet at a vanishing point (far to the left in the diagram). At this point, the x and y coordinates satisfy the definition for each of these lines. Thus, y = −0.061 × x + 5.297 = −0.030 × x + 6.753. x is solved to be −46.780 and y is 8.135. The coordinates of the vanishing point thus allow definition of the line joining the vanishing point to the chin as: y = (7.548 − 8.135)/(5.182 + 46.780) × (x + 46.780) + 8.135, which simplifies to y = −0.011 × x + 7.607. Specifically, at the x-coordinate of the malar complex (4.036), the y-coordinate (ie, bottom of arrows “a” and “b”) is found to be 7.516. The relative height of the malar complex as the ratio of “a” to “b” is thus (7.516 − 5.538)/(7.516 − 5.053) = 0.807, which is almost exactly the value shown in Figure 1, generated using (φ + 0.5)/(φ + 1.0) ≈ 0.809. It should be noted that this individual was not one of the subjects presented in this study.
Variability due to Different Images
Variability due to Within- and Between-Reader Differences
Fig. 3.Comparing population’s average cheek height ratio to that predicted by the Golden Ratio. Dashed line represents (φ + 0.5)/(φ + 1) (≈0.809) of height from chin to canthus. The average ratio for our study population is 0.793 (as is that for females alone). Demographic groups include males and females, those under 30 years and those over 31 years, those under 25 years and those over 37 years, and whites and Hispanics. Results for various demographic subgroups are shown as mean ± SD. For this subject, the measured distance from chin to canthus is 10.8 cm, and the difference between our population’s average malar prominence height and the Golden Ratio height is 1.73 mm.
Malar Prominence Height Ratio in Various Age Groups