Ethnic pride and the increasing emphasis on preserving ethnicity in aesthetic and reconstructive medicine has led to a greater need for facial anthropometric data specific to localized geographical populations. The "classical" anthropometric measurements often cited in academic literature are valuable, but they don't fully account for the distinct differences in facial anthropometric norms between various populations and racial groups.
The idea of innate geometric norms governing the makeup of a "normal face" can be traced back to Ancient Egypt and Greece. Renaissance artists further refined this concept with the "neoclassical canons," using Phi as the "divine" ratio to describe the relationship between key anatomical measurements and dividing the face into equal "horizontal thirds and vertical fifths."
Illustration of the human face divided up into the “neoclassical canons” of vertical fifths and horizontal thirds of the face. Examples of the golden ratio as it relates to various measurements of the face represented by coloured blocks.
Limitations of Classical Anthropometry
Classical descriptions of anthropometry have limitations, especially when observing differing ethnic groups. The African nose, for example, has been studied to understand the key differences that contribute to its overall shape. The terms "African," "Negroid," and "Platyrrhine" nose have become synonymous with a shortened columellar, decreased tip projection, wider alar, and broader nasal dorsum. However, this definition is problematic because it generalizes a vast population of nonhomogeneous people with origins spanning an entire continent and beyond.
This problem was recognized by Ofodile et al., who sought to further define the heterogeneous population of African Americans into “Afro-Indian,” “Afro-White,” and “African.” Building on this work, Porter et al. studied the African American female nose in 2003. They found a decreased columellar height to lobule ratio, a high variability in nasal base shape and axis, a wider nasal width in comparison with intercanthal distance, a more acute nasolabial angle, and an increased nasofrontal angle when comparing with White subjects.
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Three main nasal base/axis relationships were also identified in this study:
- Triangular base/vertical axis
- Oval base/horizontal axis
- Trapezoidal base/inverted axis combinations corresponding to Farkas classification 3, 4, and 7
Nostril base/alar axis relationship as adapted from the original work of Farkas et al in 1983. A, Triangular base/vertical axis. B, Oval base/horizontal axis.
A “cookie-cutter” approach when treating individuals of different cultures, geographical groups, and races is no longer acceptable. Data for the young Black South African female face have yet to be studied in sufficient detail and with large enough numbers to grant significantly powered results.
Study on Facial Anthropometric Norms of Young Black South African Women
A study was conducted to determine the facial anthropometric norms of young, Black, South African women. In total, 156 Black female students from Sefako Makgatho University between 18 and 25 years of age, with a normal dental occlusion and a normal body mass index were included in the study.
Anterior, lateral, and basal view photographs were taken of the participants’ faces using standardized photographic techniques. Statistical analysis of data was performed to determine the mean and standard deviation (SD) values of each measurement. The data were compared with the results of similar studies found in a literature review of Black African faces from Central and Northern Africa, African American populations, and North American White populations using individual Student t tests.
Read also: Comparing Africa and North America
The demographic analysis showed a mean age of 21 years and a BMI of 21.8 in the study group. A comparison of general facial dimensions demonstrates many statistically significant differences between ethnic groups when compared with the index South African study.
Of more interest are the relative and ratio-based measurements of each measurement within the entire face. The midface and lower face of South African women tends to be similar in height, with means of 69.3 ± 5.1 mm and 67.8 ± 5.44 mm, respectively, whereas the upper facial height tends to be shorter (60.2 ± 6.96 mm). The mean facial width (bizygonal) in the index study was significantly larger than that of the participants from Nigeria, Kenya, and Sudan as well as North American White participants, whereas there was no significant difference in African American participants. The mean intercanthal distance was found to be 34.7 ± 3.3 mm in length. The mean intercanthal distance to facial width ratio of 0.25 ± 0.02 or 25% of the facial width. The mean canthal tilt in participants showed a superolateral inclination of the lateral canthus in comparison to the medial canthus of 6.9 ± 2.7 degrees.
Ideal Proportions and Achieving Them on Ethnic Faces
Nasal Measurements
Tables 11 and 12 summarize the linear and angular nasal measurements from the index and international studies. Nasal length was found to have a mean of 38.8 ± 3.78 mm. The projection of the radix from the corneal plane was 7.8 ± 3.18 mm, which may guide the rhinoplasty surgeon on the need for dorsal augmentation. The tip projection with a mean of 21.5 ± 2.9 mm, together with a significantly larger nasofrontal angle, shows a less-projected nasal tip compared with ethnicities examined in other studies. This finding is consistent with a nasofacial angle of 31.3 ± 3 degrees and columellar length of 8.2 ± 1.69 mm. The nasolabial angle approximates that of Kenyan participants but is unsurprisingly less than that of North American White participants, indicating an inferiorly rotated, flatter nasal tip in comparison.
The mean interalar width is 42.9 ± 3.1 mm, which was significantly wider than those of other studies, and the interalar to intercanthal width ratio shows the width of the nose to be (24.5 ± 12.2)% larger than the intercanthal distance. Other key factors include an alar flare of 1.7 ± 0.9 mm, and a wide, rounded lobule measuring 25.0 ± 2.5 mm or rather, (63.7 ± 7.1)% of the nasal width.
Lip and Chin Measurements
Ethnic comparison of the lips of the current study population with those from other populations reveals decreased upper vermilion height but no significant difference in lower vermillion height when compared with Kenyan counterparts. Lip projection in relation to the Ricketts E-line is classically described as the upper lip falling 4 mm behind and the lower lip falling 2 mm behind the E-line. The index population, however, has significantly more protrusive lips with a mean of 2.4 ± 2.1 mm and 5.2 ± 2.2 mm protrusion beyond the E-line for the upper and lower lip, respectively.
Read also: Complex Realities of Northern Black Life
The mean mandibular height measured from mentolabial crease to menton was 43.6 ± 4.4 mm in this study population. In this sample, the mean chin projection indicated the chin fell 10.2 mm behind this line. The mean depth of the mentolabial sulcus was 4.5 ± 1.3 mm.
Summary of Key Findings
There are significant differences in facial anthropometric measurements between Black South African women and those from other ethnic and geographical backgrounds. The general facial proportions of young Black South African women are similar to those of Kenyan and Nigerian populations with upper facial heights being less than that of the lower and midface, thus deviating from the neoclassical canon of equal horizontal thirds. The intercanthal distance makes up approximately 25% of the facial width and, together with the nasal width that is larger than the intercanthal distance, deviates from the neoclassical canons of equal fifths. There is a gentle superolateral canthal tilt of 6.9 degrees on average. The nose is generally flatter in comparison with other populations, indicated by a wider nasofrontal angle and decreased tip projection. The nasal base is generally wider than that of the other populations examined. The nasolabial angle is also more acute than that of White people, indicating a more inferiorly rotated tip, and flatter nose. The nostril base/axis of inclination subtype is generally that of a horizontal or inverted axis. The lips are full, with an upper to lower vermillion ratio approximating 1:1.
This study highlights the nuance and sensitivity required to treat patients from varying ethnicities such as that of the Black South African woman. Furthermore, there may also be a degree of tribal variation within the South African population that was not fully elucidated in this study due to lack of sufficient representation from all tribal groups.
The “aesthetic ideal” of this population is to be found within the “normal” ranges detailed in this study. Clinicians treating patients of varying or mixed ethnic backgrounds may find themselves needing to use multiple data sets from different populations. This study has shed light on the need for a new data set for the Black South African woman and, indeed, those of all ethnic backgrounds to guide the modern healthcare professional in facial reconstruction and cosmetic and dental interventions.
