The Concept of Ideal Caucasian Male Lips: An Anthropometric Analysis of the Lower Third of the Face

Abstract

Background

The lips play a significant role in determining the aesthetic perception of a human face. However, there are little data on the perioral region morphometry of attractive males.

Objectives

This study investigates the morphology of the lower third of the face, including the lips and jawline, of attractive young Caucasian males.

Methods

A complex semi-automatic photogrammetric analysis of faces of male photo models (n = 300) of the Caucasian race, aged 18 to 39 years, was performed. Linear, angular, and surface area parameters were evaluated. In addition, an Averaged Body Contours image was created, providing the graphical summarization of facial size and shapes of all analyzed individuals.

Results

The height of the lower third of the face equaled 0.35 ± 0.03 of the total facial height. The average lip width was 50.98 ± 3.74 mm. The upper vermilion height was significantly lower than the lower vermilion height (5.9 ± 1.62 vs 11.15 ± 1.88 mm, P < 0.01). The lip obliquity angle was found to be 1.01° ± 0.73°. The area surface of the lower lip vermilion was considerably larger than the vermilion of the upper lip (P < 0.01).

Conclusions

The vast amount of morphometric data, including the novel presentation method as an Averaged Body Contours image, on the attractive male’s lower third of the face may provide the surgeons with practical guidelines for lip surgical and nonsurgical rejuvenation procedures. It may also support the perioral region reconstruction and sex reassignment surgery in achieving satisfactory results.

See the Commentary on this article here.

The lips play a significant role in determining the aesthetic and emotional perception of a human face. That is why lip rejuvenation procedures have gained such popularity in the last 2 decades, especially labial volume augmentation with dermal fillers and lipofilling.^1-5 However, distortion of lower face natural proportions may lead to disastrous results. Therefore, a clinician must know what factors contribute to attractive lips.

Since the beginning of art, humans have tried to establish a universal concept of facial beauty. Ancient Greeks attempted to characterize attractiveness by establishing ideal proportions and symmetry rules.^5-9 Their classical canons of beauty were later adopted and modified by Renaissance artists such as da Vinci and Dürer.^5-7 The search for an objective definition of attractive lips continues in modern times. Numerous studies on this subject have been conducted, including direct anthropometric measurements popularized by Farkash et al, qualitative and quantitative assessment of facial photographs, and analysis of 3-dimensional (3D) models.^10-16 However, despite the centuries of debate and search for the ideal beauty concept, there is currently no widely accepted agreement on facial attractiveness determinants.^15-17 It also applies to the lip aesthetics. Perception of beauty is subjective in nature and seems to be confounded by multiple factors, such as culture, gender, age, or socioeconomic status.^15,17-21

Most of the studies on lip morphology and attractiveness focus on females.^5,18,22-25 There are little data in the literature on the male perioral region and lower third of the face. The senior author has observed in his practice the increased interest in lip augmentation procedures among young men in recent years. Lack of detailed knowledge on men’s lips constitutes a significant clinical problem not only for aesthetic procedures but also reconstructive and gender reassignment surgery.

The aim of the this study was to investigate the young Caucasian males’ lip morphology and their relationship with various face components. It is worth emphasizing that with the utilization of our novel analytic software, we were able not only to obtain a vast amount of anthropometric data but also to generate the detailed graphical summarization of contours of the lower third of the face of the attractive male.

METHODS

Study Material

This study followed the Declaration of Helsinki and was reviewed and approved by the Medical Centre of Postgraduate Education (Warsaw, Poland) IRB. We conducted a search of digital photographic website databases of 8 prominent model management agencies from the United States, Canada, and Europe. Face photographs of professional male models of the Caucasian race were included in the study if the inclusion criteria presented in Table 1 were met. Black-and-white photographs were also included if they enabled reliable distinction of all facial contours. Because not every database provided the model’s age, after the initial selection, each male with unknown age was independently assessed by 2 evaluators. If at least 1 evaluator considered the individual’s age to exceed the established age range, the photograph was excluded from the study.

Table 1.

Inclusion and Exclusion Criteria for the Study Group

Inclusion criteria	Exclusion criteria
Male of Caucasian race Age group: 18-39 y Facial photography in frontal view Relaxed, neutral expression of face Eyes open and lips closed Head in upright position in Frankfort’s plane	Wearing eyeglasses Hairstyle preventing identification of Trichion landmark Dense facial hair preventing clear distinction of facial contours and outline

A.I.D. System and Assessment Protocol

For the anthropometric evaluation in this study, we used the A.I.D. system (Warsaw, Poland), an analytic software developed as a private, non-commercial initiative. This novel computer program was explicitly designed to enable researchers and clinicians to perform a precise and complex anthropometric analysis of the face. Straightforward utilization, achieved with a step-by-step process of evaluation and a system of textual and graphical instructions, allows obtaining a reliable morphometric assessment even for users without any knowledge or experience with anthropometry.²⁶ The nasolabial and the lower face region analysis with the A.I.D. software has been validated in the past on faces of healthy individuals and adult patients after cleft and lip palate treatment.^26,27 Analysis with the A.I.D. system was found to be equally reliable and nearly 10-fold faster than the reference ImageJ (National Institutes of Health, Bethesda, MD), an analytic tool commonly employed for photogrammetric assessment. No significant differences in measurements were found between the medical professionals and laypeople evaluators. The A.I.D. system provided strong inter-rater and intra-rater variability for linear (0.898 and 0.928, respectively), angular (0.894 and 0.892, respectively), and area measurements (0.964 and 0.963, respectively) in the frontal face view.²⁷

Employing the A.I.D. software, the evaluator (senior author) conducted a semi-automatic anthropometric and morphometric analysis of acquired facial photographs in 2 evaluation sessions. The sessions were scheduled at 2-week intervals and had a random sequence of analyzed images to minimize the risk of memorization bias. The evaluator manually identified and labeled specific landmarks and areas of the entire face under 3× magnification view, following the instructions provided by the computer system (Video). Regarding the lower third of the face, a set of landmarks described by Farkas was mainly used (Figure 1; Table 2).^10-13 A metric calibration was conducted for each photograph, enabling the transformation of pixels to millimeters. For this purpose, an iris diameter was set equal to 12 mm, which is an actual mean diameter of the male iris. This approach is a reliable method of metric calibration of frontal view photographs commonly employed in similar studies in the past.^28,29

Table 2.

Summary of Anthropometric Landmarks Employed in the Lower Third of the Face Analysis

Abbreviation	Landmark	Description
ChR	Cheilion right	Most lateral point of labial commissure on right side
ChL	Cheilion left	Most lateral point of labial commissure on left side
Sto	Stomion	Midline point at junction of upper and lower lip vermillion
Ls	Labial superius	Lowest vermilion point of Cupid’s bow
CpR	Crista philtri right	Point at right peak of Cupid’s bow
CpL	Crista philtri left	Point at left peak of Cupid’s bow
Li	Labial inferius	Midpoint of mucocutaneous border of lower lip
Ml	Mentolabial sulcus	Midpoint of mentolabial sulcus
Me	Menton	Most inferior midline point of soft tissue chin
Sn	Subnasale	Midline point at junction of columella and upper lip skin
SbalR	Subalar right	Point at lower inner limit of right alar base
SbalL	Subalar left	Point at lower inner limit of left alar base
AlR	Alar right	Most lateral point of right nasal alae contour
AlL	Alar left	Most lateral point of left nasal alae contour
Tr	Trichion	Midline point at junction of hairline and forehead

Figure 1.

(A) Anthropometric landmarks of the lower third of the face and nose region used in the study. Descriptions of the abbreviations are presented in Table 2. (B) Types of investigated linear distances: (H) the horizontal distance between two landmarks; (V) the vertical distance between two points; and (Dr) the direct distance between two landmarks. (C, D) The summary of investigated angular parameters of the lips.

Video 1.

Watch now at http://academic.oup.com/asj/article-lookup/doi/10.1093/asj/sjac057

After completing landmark labeling, the software automatically calculated a set of linear, angular, and surface area measurements (see Supplemental Material). The results were then exported to an Excel spreadsheet (Microsoft Corp., Redmond, WA). With the utilization of our novel algorithm, the A.I.D. system also generated the Averaged Body Contour (ABC), a graphical summarization of facial contours of all evaluated individuals.³⁰

Statistical Analysis

The Pearson’s correlation coefficient and the Bland-Altman index (BAIx) were employed for intra-observer reliability evaluation, thus enabling a quality control of the measurements performed in the study. A mean and standard deviation were calculated for every photogrammetric measurement. The symmetry of paired anthropometric parameters was analyzed with the independent t test.

Proportions between the jawline contour and the characteristic landmarks of the lips and nose were described with mean, standard deviation, median, and 10th and 90th percentile and quartiles. In addition, a receiver operating characteristic curve was employed to estimate ratio ranges defining the proportional lower third of the face.

The statistical significance threshold was set at 5% (P ≤ 0.05). All calculations were carried out with IBM SPSS Statistica v.13 (TIBCO Software Inc., Palo Alto, CA).

RESULTS

We successfully performed 2 sessions of complex anthropometric analysis of the face of 300 professional male photo models of the Caucasian race. However, for the purpose of this study topic, only results related to the lower third of the face evaluation shall be presented.

Anthropometric Analysis

According to the statistical analysis, high intra-observer reliability for all 3 types of measurements was achieved, confirming their results’ correctness. The Pearson’s r was 0.94, 0.85, and 0.97 for the linear, angular, and surface area measurements, respectively. For linear parameters, BAIx was 3.7%. For angular and surface area measurements, BAIx was found to be 3% and 3.85%, respectively.

Results of photogrammetric analysis of the lower third of the face are presented in Table 3. Statistical analysis showed no significant asymmetry between any of the paired anthropometric components of the lip region. Table 4 presents a set of proportion indices of selected measurements of the perioral area and other facial regions.

Table 3.

Lips and Perioral Region Measurements^a

Type of parameter	Parameter	Both sides	Right side	Left side	P
		Mean ± SD	Mean ± SD	Mean ± SD
Linear parameters,mm	Total facial height (V)	185.51 ± 12.27			n/a
	Lower third of face height (V)	65.02 ± 6.02			n/a
	Facial width: lower third of facial height level (H)	122.18 ± 7.04			n/a
	Facial width: labial commissure level (H)	112.34 ± 8.72			n/a
	Lip width (D)	50.75 ± 3.65			n/a
	Lip width (H)	50.98 ± 3.74			n/a
	Distance between cheilion and crista philtri (D)		20.25 ± 2.06	19.89 ± 2.27	0.001
	Distance between cheilion and crista philtri (H)		18.67 ± 1.98	18.26 ± 2.08	0.001
	Distance between cheilion and labial superius (H)		25.51 ± 1.98	25.51 ± 2.19	0.950
	Total height of upper lip (V)	21.54 ± 2.49			n/a
	Cutaneous upper lip height (V)	15.64 ± 2.27			n/a
	Upper vermilion height (V)	5.9 ± 1.62			n/a
	Total height of lower lip (V)	18.21 ± 2.21			n/a
	Cutaneous lower lip height (V)	7.06 ± 1.94			n/a
	Lower vermilion height (V)	11.15 ± 1.88			n/a
	Chin height (V)	25.69 ± 3.21			n/a
	Cupid’s bow (Philtrum) width (D)	14.19 ± 2.32			n/a
	Cupid’s bow (Philtrum) width (H)	14.22 ± 2.3			n/a
	Cupid’s bow arm width (D)		7.54 ± 1.29	7.96 ± 1.35	<0.001
	Cupid’s bow arm width (H)		6.98 ± 1.28	7.40 ± 1.29	<0.001
	Cupid’s bow arm height (V)		8.03 ± 1.66	7.87 ± 1.69	<0.001
	Philtrum height (V)	15.82 ± 4.59			n/a
	Philtrum column height (V)		12.97 ± 2.21	13.03 ± 2.21	0.033
	Distance between crista philtri and subalar (D)		15.18 ± 2.24	14.9 ± 2.17	<0.001
	Distance between crista philtri and subalar (V)		14.34 ± 2.17	14.26 ± 2.21	0.030
Angular parameters, o	Lip obliquity	1.01 ± 0.73			n/a
	Cupid’s bow angle	138.27 ± 8.26			n/a
	Cupid’s bow arm angle		68.59 ± 4.6	69.68 ± 4.2	<0.001
	Lip spread angle	101.81 ± 8.85			n/a
Surface area parameters, cm2	Upper lip vermilion area	28.54 ± 7.47			n/a
	Lower lip vermilion area	42.2 ± 8.17			n/a

^aD, direct distance; H, horizontal distance; n/a, not applicable; SD, standard deviation; V, vertical distance.

Table 4.

Selected Ratios of the Lower Face Parameters^a

Parameters ratio	Mean ± SD
Lower third of face height (V): total facial height (V)	0.35 ± 0.03
Lip width (H): lower face width (subnasion level) (H)	0.42 ± 0.02
Lip width (H): lower face width (labial commissure level) (H)	0.46 ± 0.03
Intercanthal distance (H): lip width (H)	0.62 ± 0.06
Nasal width (H): lip width (H)	0.72 ± 0.05
Nasal base width (H): lip width (H)	0.45 ± 0.05
Cupid’s bow (philtrum) width (H): lip width (H)	0.28 ± 0.04
Total vermilion height (V): lip width (H)	0.33 ± 0.06
Upper vermilion height (V): lip width (H)	0.12 ± 0.03
Lower vermilion height (V): lip width (H)	0.22 ± 0.04
Philtrum height (V): lip width (H)	0.31 ± 0.07
Cupid’s bow right arm width (H): Cupid’s bow left arm width (H)	0.95 ± 0.16
Total height of upper lip (V): lower third of face height (V)	0.33 ± 0.02
Total height of lower lip (V): lower third of face height (V)	0.28 ± 0.03
Chin height (V): lower third of face height (V)	0.4 ± 0.03
Total height of upper lip (V): total height of lower lip (V)	1.19 ± 0.16
Cutaneous upper lip height (V): total height of upper lip (V)	0.73 ± 0.06
Upper vermilion height (V): total height of upper lip (V)	0.28 ± 0.06
Cupid’s bow right arm height (V): Cupid’s bow left arm height (V)	1.02 ± 0.07
Cupid’s bow right arm height (V): upper vermilion height (V)	1.39 ± 0.17
Cupid’s bow left arm height (V): upper vermilion height (V)	1.36 ± 0.17
Cupid’s bow right arm height (V): Cupid’s bow (Philtrum) width (H)	0.58 ± 0.15
Cupid’s bow left arm height (V): Cupid’s bow (Philtrum) width (H)	0.57 ± 0.15
Philtrum height (V): total height of upper lip (V)	0.74 ± 0.15
Philtrum right column height (V): philtrum left column height (V)	1 ± 0.04
Cutaneous lower lip height (V): total height of lower lip (V)	0.39 ± 0.09
Lower vermilion height (V): total height of lower lip (V)	0.62 ± 0.09
Cutaneous lower lip height (V): chin height (V)	0.28 ± 0.08
Cutaneous upper lip height (V): cutaneous lower lip height (V)	2.37 ± 0.7
Upper vermilion height (V): lower vermilion height (V)	0.53 ± 0.12
Upper lip vermilion area: lower lip vermilion area	0.68 ± 0.13

^aH, horizontal distance; SD, standard deviation; V, vertical distance.

Descriptive statistics of the aspect ratios of the jawline outline and distinctive landmarks of the lips and nose are summarized in Table 5. Parameters ratio ranges characteristic for the proportional aesthetic jawline were calculated based on the receiver operating characteristic curve data analysis. In 40.33% of assessed men (n = 121), all 6 evaluated ratio values were in the range between the 10th and 90th percentiles (Table 6).

Table 5.

Proportions Between the Jawline Outline and Distinctive Landmarks of the Lower Face^a

Demographic	Parameters ratio	Mean ± SD	Min	10th Percentile	Q1	Median	Max	90th Percentile	Q3
All males	Al-FR (V): Al-FR(H)	1.60 ± 0.14	1.22	1.45	1.52	1.62	2.08	1.79	1.71
	Al-FL (V): Al-FL(H)	1.65 ± 0.13	1.35	1.49	1.57	1.64	2.29	1.83	1.74
	Al-F (V): Al-F (H)	1.64 ± 0.13	1.22	1.47	1.54	1.63	2.29	1.81	1.72
	Ch-FR (V): Ch-FR(H)	1.19 ± 0.12	0.73	1.05	1.1	1.18	1.58	1.33	1.26
	Ch-FL (V): Ch-FL(H)	1.24 ± 1.12	0.91	1.09	1.16	1.24	1.59	1.4	1.32
	Ch-F (V): Ch-F(H)	1.21 ± 0.12	0.73	1.06	1.13	1.2	1.59	1.37	1.29
	Cp-FR (V): Cp-FR(H)	1 ± 0.08	0.71	0.9	0.95	1	1.26	1.11	1.06
	Cp-FL (V): Cp-FL(H)	1.02 ± 0.08	0.79	0.93	0.97	1.03	1.33	1.12	1.07
	Cp-F (V): Cp-F(H)	1.01 ± 0.08	0.71	0.91	0.96	1.01	1.33	1.11	1.06
	Al-F (V): Al-F (H)	1.64 ± 0.08	1.46	1.52	1.59	1.64	2.29	1.75	1.7
Average parameter proportions: males with all ratios values in 10th-90th percentile range (n = 121)	Ch-F (V): Ch-F(H)	1.21 ± 0.08	1.05	1.10	1.15	1.21	1.59	1.32	1.28
	Cp-F (V): Cp-F(H)	1.01 ± 0.05	0.9	0.94	0.97	1.01	1.33	1.07	1.05
	Al-F (V): Al-F (H)	1.63 ± 0.16	1.22	1.43	1.51	1.62	2.29	1.85	1.76
Average parameter proportions: males without all ratio values in 10th-90th percentile (n = 179)	Ch-F (V): Ch-F(H)	1.21 ± 0.14	0.73	1.03	1.11	1.2	1.59	1.41	1.32
	Cp-F (V): Cp-F(H)	1.01 ± 0.1	0.71	0.89	0.94	1.01	1.33	1.14	1.09

^aAl, Alar; Ch, cheilion; Cph, Crista philtri; F, lower face outline; H, horizontal distance; L, left side; Min, minimum; Max, maximum; Q, quartile; R, right side; SD, standard deviation; V, vertical distance.

Table 6.

Ideal Proportion Ranges Between Male Jawline Contours and Lips and Nose Landmarks^a

Parameters ratio	Ideal proportion range	OR (95% Cl)
Al-F (V): Al-F (H)	1.54-1.79	3.88 (2.29 to 6.59)
Ch-F (V): Ch-F(H)	1.1-1.34	4.24 (2.39 to 7.51)
Cp-F (V): Cp-F(H)	0.96-1.08	4.18 (2.54 to 6.87)

^aAl, Alar; Ch, cheilion; CI, confidence interval; Cph, Crista philtri; F, lower face outline; H, horizontal distance; OR, odds ratio; V, vertical distance.

Average Body Contours

The results of the anthropometric evaluation of all faces were also presented as a single figure generated by the A.I.D. software employing the ABC algorithm.³⁰ The ABC parameter shown in Figure 2 graphically summarizes all analyzed faces in the form of silhouettes and landmarks. Despite the analysis of the whole face, only contours of the facial outline and perioral region components are included in this figure.

Figure 2.

Averaged Body Contours enabling graphical summarization of all analyzed males' faces. (A) The facial outline and the lower third region components are presented with palpebral fissures. (B) An ABC image with lips and nasal landmarks imposed on the facial contours.

DISCUSSION

The interest of male individuals in cosmetic surgery and non-surgical procedures for the perioral region seems to have increased in recent years.^1-5,7 Although there is an evident sexual dimorphism of the lower third of the face between men and women, to this date, little is known about attractive male lip morphology.^31-33 Currently, most of our quantitative knowledge on male lips, especially of the Caucasian population, is based mainly on anthropometric studies conducted by Farkash et al.^10-16 However, their research focused mainly on obtaining normative data of a healthy population and not attractive individuals. Also, their analysis provides information on only a few perioral morphometric parameters. That is why our study was focused on defining the objective criteria of aesthetically pleasant lips. We conducted a complex facial evaluation of an unprecedented number of 300 males considered attractive, making it the largest study on this subject.

Attractiveness is a subjective term; therefore, it is difficult to reliably evaluate and describe. Its perception may be influenced by age, gender, and ethnic and cultural background.^15,17-21 In the last 2 decades, worldwide access to the internet and the rapid development of social media has increased the globalization process.^34,35 As a result, marketing and fashion agencies, in a way, impose a universal canon of beauty worldwide, unifying the goal of aesthetic surgery. That is why we, like many other authors, decided to assess the faces of professional photo models in our study.^36-40 This approach, involving a study group that can be generally considered attractive, reduces the limitation, which is the subjective sense of beauty among various individuals. This way, the predictive power score of our study’s morphometric data can be considered very high (close to a value of 1, which indicates a perfect score) for attractive males of the Caucasian race. If future studies provide a similar set of anthropometric data of a representative populational group, then the above-mentioned predictive power score can be investigated for typical males of similar and older age groups.

Our conclusions based on numeric anthropometric data and ABC figure analysis were summarized in Table 7. The obtained results indicate the concept of equal horizontal thirds of the face applies to some level for attractive Caucasian males. The height of the lower face, measured from the subnasale to the menton, equals 0.35 ± 0.03 of the total facial height. This disproves the concept that the lower third of the face tends to be larger than the upper and middle thirds in Caucasians.^5,7,12 The upper lip height is one-third of the height of the lower third of the face (0.33 ± 0.02). Skomina et al., in their anthropometric study on the small normative group of Caucasian males, found this ratio to be 0.4.⁴¹ The lower lip was observed to be slightly shorter than the upper lip. This is in accordance with the studies by Farkas and other researchers.^10-12,42,43 The total lower lip height equals approximately 0.28 ± 0.03 of the height of the lower third face and 0.85 ± 0.16 of the whole upper lip height. In our male group, the average chin height was 25.69 ± 3.21 mm, which equals 0.4 of the lower face height. This value is consistent with the findings of other authors (28.63 mm).⁴²

Table 7.

Characteristics of Attractive Caucasian Male Lips and the Facial Lower Third Based on Numeric Morphometric Data and ABC Figure Analysis^a

What makes an attractive male lip and facial lower third?

Lower face height equals one-third of total face height

Jawline’s (chin bottom) horizontal contour length approximately equal to lip width

Jawline’s sloped contour ends at labial commissure level

Lip width approximately equal to facial width at labial commissure level

Upper lip constitutes approximately 0.33 and chin 0.4 of lower third of face height

Lower lip vermilion larger than upper lip vermilion, with its height being approximately 2 times larger than upper one

Cupid’s bow is characterized by

• Width of one-third of lip width

• Wide philtrum

• High Cupid’s bow arms with height ratio to upper vermilion height approximately 1.4

• Cupid’s bow angle of approximately 138°

^aABC, Average Body Contour.

We found the male lips to be approximately 51 mm wide. Other studies have found this parameter to be 47.2, 52.2, and 54.5 mm.^10-12,41,42 In our group, the lip width constituted 0.42 ± 0.02 of facial width at the nasal base level (subnasal point), a similar value (0.4) suggested by other authors.⁷ However, we prefer to compare it with the facial width at the labial commissure level, which was 0.46 ± 0.03. Following this ratio might be helpful in planning the lateral commissuroplasty surgery.

Relatively little is known about the morphometry of male vermilion. Some authors claim no gender difference between the upper and lower vermilion height and that the upper vermillion is shorter.^32,42-44 Our study confirms that the upper vermillion is indeed smaller (P < 0.001). Upper vermilion height equals 0.28 ± 0.06 of the total height of the upper lip. Interestingly, the same value of this ratio was found by Penna et al in their study on attractive males.⁴⁵ On the other hand, the lower vermilion constitutes 0.62 ± 0.09 of the height of the lower lip, which is more than previously reported by Raschke et al.⁴⁴ The same authors also observed the cutaneous upper lip height to be 1.3 times larger than its lower lip counterpart. Our measurements show this proportion to be almost 2 times higher (2.37 ± 0.7).⁴⁴ The proportions of the lower vermilion height and surface area to the upper vermilion are 1.89 and 1.48, respectively. This finding disagrees with the golden ratio concept, according to which those values should equal 1.618.⁷ Therefore, this rule may be considered invalid for attractive Caucasian males.

Numerous studies demonstrated that the lips of the elderly are characterized by philtrum excess and decreased volume and height of the upper vermilion.^5,7,44 Thus, the success of rejuvenation procedures requires the possession of detailed knowledge about attractive lip features, especially the Cupid’s bow. Our complex analysis of this structure shows that a wide philtrum and high arms are considered attractive (Table 4). The average height of the Cupid’s arm in our group was 7.95 mm, higher than the 7.1 mm determined by Sawyer et al.⁴⁶ The Cupid’s width of 14.22 ± 2.3 mm observed by us is also considerably higher than the 10- to 11-mm values range reported in previous studies.^11,12,25 The mean Cupid’s bow angle was determined as 138.27° ± 8.26°. The Cupid’s bow width to lip width ratio should equal approximately 0.28 ± 0.04, and the average height of the bow’s arm to the upper vermilion height ratio should be 1.38 ± 0.17. Interestingly, we found a significant difference between both arm heights (P < 0.001), which does not refute the perception of their attractiveness. This observation seems to confirm the suggestions of other researchers that proportions and not symmetry mainly influence facial attractiveness.^15,41

One of the limitations of every complex anthropometric study is that it is difficult to comprehend its results presented as vast numeric data. Tables 2 to 4 are great examples of that. Moreover, no matter how many numeric parameters are used, they still fail to describe the structure’s shape. Facial components with many curves, such as lips, are significantly underrepresented. To overcome these limitations, we developed the ABC concept. This novel method, integrated with the A.I.D. software, allows for summarization of the measurements’ results of the entire study group in the form of a single figure.³⁰ It provides the graphical presentation of the group’s quantitative morphometric data, making it easy to comprehend. But most of all, the ABC enables the visualization of shapes and contours. In our opinion, this new analytic ability opens a new frontier in the field of anthropometric and surgical outcome evaluation studies. ABC provides a deep insight into face morphology at a previously unavailable level of detail. This method may change the way of morphometric data presentation, becoming a standard addition to studies reporting anthropometric measurements or evaluating surgical outcomes in a quantitative manner.

Our methodology also included the evaluation of the outline of the lower third of the face. In addition to the graphical presentation of the jawline contour with the generated ABC image, we have also investigated its relationships to lip and nasal landmarks (Figures 2, 3). The results analysis indicates that a high jaw characterizes an attractive lower face, along with a broad lower chin segment, which width is considerably similar to the lip height.

Figure 3.

The ideal proportion of distances between the jawline contour and landmarks of the lips and nose in an attractive male face.

Marquardt created an ideal facial proportions mask based on the golden ratio of 1:1.628.⁴⁷ Although many have found it helpful, numerous studies have not confirmed the relationship between the golden ratio and facial aesthetics. According to some, the hexagonal mask tends to masculinize the feminine face and does not seem to represent appropriately many attractive facial features.^15,24 It is also not universally applicable due to its problematic utilization as a reference in research and clinical settings.²⁴ Moreover, the golden ratio concept, along with many neoclassical facial canons, does not apply to all races.^48,49 The ABC enables the creation of a face mask distinctive for a specific population group of a certain age, gender, and race. Because its design is based on individualized anthropometric measurements and not a mathematical conception, we find it more reliable. The method is simple and time-efficient, and the A.I.D. software is distributed free of charge, making the ABC a universal method adapted for both research and clinical settings. The ABC may become a standard in morphometric data presentation in the future.

Our study expands the knowledge on attractive lip morphology of men. To our knowledge, based on extensive literature analysis, no work similar to ours on male lips regarding the number of evaluated individuals and complexity of anthropometric evaluation has been published. Photogrammetric analysis can be very time-consuming and tedious, especially when performed without a proper analytic tool. To our knowledge, no single publication on men’s lips and lower face region, compared with our study report, has described so many anthropometric parameters and proportions, not to mention summarizing them along with facial contours in a graphical form. The various sets and the low number of parameters presented per paper make it difficult for clinicians and other researchers to find and eventually compare the ones they are interested in. That is why we aimed to multiple data sets for future reference.

The surgeon’s understanding and appreciation of facial features determining its pleasant appearance are crucial to plan perioral region rejuvenation. Therefore, the results presented in this paper can be applied directly to clinical practice, supporting lip surgical and non-surgical cosmetic procedures, especially its elongation or augmentation with fillers or lipofilling. Our findings may also be applied to reconstructive surgery of the lips. The described concept of the aesthetic lower third of the face may be employed as a guide for corrective surgery of congenital and acquired defects due to injuries or oncological treatment. For example, the generated ABC figure of the lips and lower face may be employed as a guideline for surgical correction of lip deformation in patients after primary cleft lip and palate treatment. Another important field of application is facial surgery oriented to achieve the masculinization effect. The most prominent example is female-to-male sex reassignment surgery, which may include more precise lip and jawline recontouring thanks to this study’s results.⁵⁰ Last but not least, the presented analytic method employing A.I.D. software may be utilized to obtain detailed normative anthropometric data on various population groups and enable quantitative evaluation of facial surgery outcomes.

Our study has several limitations. First of all, only face photographs in frontal view were analyzed. Although evaluation in lateral projection would provide more information on the lower third of the face, such as lip projection, the searched databases did not contain properly standardized photographs of that type. Assessment of photographs in lateral view would also enable the creation of ABC of the lateral facial contour. It would provide detailed insight into an aesthetically pleasing nasolabial angle, shape, and projection of the chin and submental-neck outline. In recent years, evaluation of 3D models has gained popularity among researchers. In our eyes, in facial morphology analysis, its most significant advantage is the ability of volume assessment, which could be employed for complex lip evaluation. However, to our knowledge, there is no open-access database containing standardized 3D scans of professional male models. Therefore, similar study based on 3D model analysis could not be conducted. Moreover, currently, 3D models can be presented in publications in both paper and virtual versions only as 2D photographs. So, even if a 3D ABC model based on multiple 3D scans was created, it would still have to be presented as a 2D figure.

Another limitation is the lack of a precisely defined age mean of the study group. It was impossible to calculate because not all analyzed photographic databases contained the models’ age information. However, we partially compensated for this limitation by confirming the chosen age span of 18 to 39 years old obtained by subjective analysis of the collected photographs by 2 independent observers. The lack of comparative analysis of an older group may be considered a limitation of this study. Indeed, such a comparison would be informative. However, our goal was to provide precise referential data for rejuvenating procedures; therefore, the young attractive individuals’ group had to be evaluated.

Another imperfection stems from the fact that only the faces of Caucasian males were evaluated. It has been shown that facial morphological features, including lips, vary significantly among races.^48,49 Therefore, the results of our study should be considered reliable guidelines only for Caucasian patients. Applying our observations to other races may lead to poor aesthetic results. That is why we shall soon conduct a similar investigation to obtain anthropometric data on male representatives of other races. Also, a comparative study between male and female photo models is currently in progress. It must also be acknowledged that the current male attractiveness cannon, much like fashion and arts trends, may be subject to change with time. A great example of such change is considering a curvaceous female body as an ideal model of beauty during the baroque era, which can be admired in the painting of Rubens and other great artists. Probably in the future, the same faith will meet the current male beauty canon promoted by the fashion and entertainment industries.

CONCLUSIONS

Compared with the vast amount of data on female lips, little is known about attractive male lips. Our study results provide a detailed quantitative concept of the aesthetically pleasant lips of Caucasian men. This knowledge, especially the ABC of the lower third of the face, may support not only lip rejuvenation procedures but also reconstructive and sex reassignment surgery in achieving satisfying natural outcomes.

Disclosures

The authors declared no potential conflicts of interest with respect to the research, authorship, and publication of this article. The development of the A.I.D. software (Warsaw, Poland) is a private, non-profit initiative of both authors of this work. The A.I.D. software is distributed free of charge. To apply for it, please contact the corresponding author of this paper.

Funding

The authors received no financial support for the research, authorship, and publication of this article.