|Year : 2022 | Volume
| Issue : 3 | Page : 164-168
Aural and nasal anthropometry: An observational study
Pratima Jaiswal1, Aastha Sharma2, Aarushi Jain3
1 Professor and Head, Department of Anatomy, GMC, Kota, Rajasthan, India
2 MBBS Student, Department of Anatomy, GMC, Kota, Rajasthan, India
3 Associate Professor, Department of Anatomy, GMC, Kota, Rajasthan, India
|Date of Submission||28-Apr-2022|
|Date of Decision||27-Jun-2022|
|Date of Acceptance||03-Jul-2022|
|Date of Web Publication||12-Aug-2022|
Departmnet of Anatomy, GMC, Kota, Rajasthan
Source of Support: None, Conflict of Interest: None
Background: Neoclassical analysis of the human face is based on assumptions that certain fixed ratios exist between parameters of a harmonious face, these relationships of the human face have been called canons. One of the facial canons is nasoaural proportion canon most commonly followed for facial reconstructive surgeries. This study aimed to determine the applicability of nasoaural proportion and inclination canon in the participants and to explore the sexual dimorphism of nasoaural parameters among them. Methodology: This observational study was performed in the department of anatomy from May 2018 to May 2019. The study participants aged from 18 to 25 years of which 50 were male and 50 were female. Nose height and ear height were measured by a digital vernier caliper. Nasofacial angle and ear angle were measured using a goniometer. All the parametric data were analyzed by t-test using MedCalc software. Results: Classical nasoaural facial canon was followed by only one (male) participant while none of the males and females followed the classical nasoaural canon. The average ratio of nose height to ear height was 0.7 in both genders. Nasoaural canon showed that nasal height and ear height were fairly correlated. The inclination canon was followed by 18% males and 8% females only. Conclusion: The ideal neoclassical canons did not seem to apply to our sample when measurements were implemented. Therefore, these cannot prove a useful basis of modus operandi in achieving esthetic goals in the Indian population.
Keywords: Angle, anthropometry, Craniofacial, Esthetic, Nasoaural
|How to cite this article:|
Jaiswal P, Sharma A, Jain A. Aural and nasal anthropometry: An observational study. Natl J Clin Anat 2022;11:164-8
| Introduction|| |
Perception of facial accord and proportions is paramount for facial corrective procedures and surgical strategies. If a deformity is present in more than one of the facial regions a liberal analysis of the soft-tissue relationship and underlying bone can elucidate the area most apt for surgical intervention. Neoclassical analysis of the human face is based on assumptions that a certain fixed ratio exists between parameters of a harmonious face, these relationships of the human face have been called canons. The canons are an appealing way of approaching facial evaluation due to their ease to remember and relevance for general assessment. Farkas et al. were the first to investigate the relevance of neoclassical facial canons. One of the facial canons is nasoaural proportion canon most commonly followed for facial reconstructive surgeries. Classically, the nasoaural proportion canon states that the height of the nose (n-sn) and ear (sa-sb) are equal and nasoaural inclination canon states that the inclination of the nasal dorsum is the nasofacial angle (NFA) is equal to the angle of ear inclination (EA) [Figure 1].
|Figure 1: Anthropometric landmarks used in the study. sa-sb: EH (Ear height), n-sn: NH (Nose height), FP: Frankfurt's plane, EA: Ear angle, NFA: Nasofacial angle, sa: superaurale (Highest point on ear auricle), sb: Subaurale (Lowest point on free margin of ear auricle), n: Nasion (Deepest point in the sagittal plane at the root of the nose), sn: Subnasale (Point at the junction of the nasal columella and upper lip), NFA: Angle between vertical line passing through nasion and nasal dorsum, EA: Angle between vertical plane and line joining sa and sb|
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The morphometric magnitude of the Caucasian nose has been frequently studied, with values considerably recorded., These values are a reference against which all rhinoplasty and nasal reconstructions are judged. More non-Caucasian persons seeking reconstructive or remedial surgery for congenital anomalies of the face and paradigms of beauty differ from one ethnic group to another. Several studies detailing facial analysis parameters among Indians, Chinese,, and African-Americans, etc., significantly differ from those of Caucasians, which means that using only Caucasian parameters will be invalid in the accomplishment of esthetics for all patients. A huge lacuna exists on the applicability and validity of the nasoaural proportion canon and nasoaural inclination canon in the Indian population. This study aimed to determine the applicability of nasoaural proportion and inclination canon in the participants and to explore the sexual dimorphism of nasoaural parameters among them.
| Materials and Methods|| |
This observational study was performed in the department of Anatomy, Government Medical College, Kota, from May 2018 to May 2019. The sample size was calculated using OpenEpi software (www.OpenEpi.com,updated 2013/04/ 06, accessed 2022/07/06) with a confidence level of 95%, a margin of error of 5%, and a response distribution of 50%. The study participants comprised 100 medically fit medical undergraduate students aged from 18 to 25 years of which 50 were male and 50 were female.
The institutional review board approved the protocol before the start of the study (No. 4, IEC/2019/1205 dated May 15, 2019). The participants in the study signed the informed consent form after explaining the procedure. All participants met the inclusion criterion of – Indian ethnicity, normal facial growth and development, and devoid of any obvious craniofacial deformity and syndromes, age group 18–25 years of both genders to reduce the effects of aging, healthy and esthetically pleasing individuals. The participants were excluded from the study that had a previous history of craniofacial surgery or treatment, any cosmetic and reconstructive facial surgery, or any congenital or acquired facial deformity.
Parameters noted were: ear height (EH) = sa-sb, nasal height (NH) = n-sn, NFA, and angle of EA [Figure 1].
All participants were seated on a stool comfortably in a closed room. After explaining the procedure to them, an anthropometer was placed adjacent to the participants. Their heads were adjusted in the Frankfurt's plane (which coincided with the horizontal scale of the anthropometer). A mirror was placed in front of the participants. After their heads were aligned in Frankfurt's plane, the participants were asked to fix their gaze on the reflection of their own eyes to prevent any movement. The Frankfurt's plane was also marked on the participant's face on their right side. The participant's posture was checked and corrected every time before taking the measurements. All the reference points were marked using a marker pen as shown in [Figure 2]a and [Figure 2]b. For the ear measurements according to Barut and Aktunc, dimensions differ between the right and left ears. Thus, for standardization, measurements were done on the right ear for height and angulations. Nasale (n) was point of maximum concavity of the nasal dorsum at the level upper lid lash line. The linear measurements were done using digital vernier calipers with accuracy of 0.02 mm and the readings were recorded in millimeters. NFA angle was measured using a goniometer by keeping the stationary arm perpendicular to the Frankfurt's plane and mobile arm along the nasal dorsum. EA was measured using a goniometer by keeping the stationary arm perpendicular to the Frankfurt's plane and mobile arm along the line joining sa and sb. All the measurements were performed and recorded thrice by the same observer and their mean was calculated for each reading. The caliper and goniometer were calibrated every time before taking the readings on the participants.
A preliminary arbitration was contemplated that the facial canon would be considered valid if the difference between the values of EH and NH, EA and NFA was below 1.5 mm or 2° for the lengths and angles, respectively. Based on this limit, the relevance of the nasoaural canons for a particular participant was categorized as valid (n-sn = sa-sb) small (n-sn < sa-sb) or large (n-sn > sa-sb). Based on this threshold, the applicability of the nasoaural inclination canons for a particular participant was categorized as valid if (EA = NFA) small (NA < EA) or large (NFA > EA). The frequencies of the valid canon and their different variants were calculated in percentage. The difference of EH and NH, NFA and EA were calculated for all the subjects and then their mean and standard deviation was evaluated. A Chi-square test was used to compare the prevalence of different variants of nasoaural proportion and inclination canon. Furthermore, a correlation was calculated by Pearson correlation coefficient between the nasal and the aural length since both the parameters when actually calculated were not equal. All the parametric data (EH and NH of male and female, NFA and EA of both genders) were analyzed by t-test using MedCalc software version 20.106 (MedCalc Software, Ostend, Belgium). The frequencies of the nasoaural proportion canon and the nasoaural inclination canon and deviants were calculated and compared by the Chi-square test.
| Results|| |
The mean measurements of nasoaural facial canon and nasoaural inclination canon are shown in [Table 1].
|Table 1: Comparison of means with their standard deviations of male and female|
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1. Nasoaural proportion canon: When NH was compared with the EH, it was not equal in any of the participants except 1%. The majority of the participants followed its variant where the EH exceeded the NH by a mean of 17.60 (±4.6) mm in males and 17.69 (±4.35) mm in females [Table 2]. The EH of male was more than the NH in 99% of the individuals [Table 3], and the classical canon was followed by one male participant, while none of the females followed the valid classical nasoaural canon. The average ratio of nose height to EH was 0.7 in both genders. Pearson correlation coefficient for comparison of measurements of nasoaural canon showed that NH and EH were fairly correlated (r = 0.38)
|Table 2: Mean difference in measurements between nasoaural proportion and nasoaural inclination canons in either sex|
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|Table 3: Comparison of nasoaural canon and nasoaural inclination canons and their variants according to sex|
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2. Nasoaural inclination canon: As shown in [Table 3], the frequencies of the nasoaural inclination canon and deviants were calculated and compared by the Chi-square test. The inclination canon applied to 18% males and 8% females only. The majority of the participants (77%) followed the variant pattern. As depicted in [Table 1] and [Table 3], the NFA was greater than EA in the whole sample. Nasoaural inclination showed that EA and NFA were poorly correlated (r = 0.07).
| Discussion|| |
Reconstructive and maxillofacial surgeons are always on a quest for desirable facial parameters concerning the racial milieu of individuals to achieve facial harmony. The neoclassical canons were initially devised by intellectuals and artists of the Renaissance and were based on classical Greek canons to explicate the associations between various areas of the head and face as a guide for artists., They are the keystone of contemporary facial analysis.
Farkas et al. are acknowledged for their vast work on recording anthropologic facial assessments of healthy individuals from diverse cultural backgrounds.,,, They worked on North American Caucasian women and found their EH to be 59.6 mm, NH 50.6 mm, EA of 18°, and NFA to be 29.9°. Hence, their findings were in line with our findings as EH exceeded the nose height and nose angle exceeded the EA in Indian females. The present study showed an average EH of 62.17 mm in males and 57.84 mm in females.
Porter and Olson measured the EH of African-American women to be 57.4 mm which is almost the same as the present study, i.e., 57.84 mm. NH was also 48 mm in females, whereas it was smaller in Indian females as it was 40.26 mm in the present study. Although the EA was 24.49° and the nose angle was 38.9° slightly different from the present study which was approximately 24.88° and 31.84°, respectively, in the whole sample. Farkas et al. analyzed the Chinese, Egyptian, and African-American populations and found NH to be 53.5 mm, 54.6 mm, and 51.8 mm in males and 51.7 mm, 47.4 mm, and 48.8 mm in females, respectively, of the three races. The present study not only evaluated the data of nasoaural facial canon using the digital vernier caliper but also their applicability in both genders than that of Porter and Olson who tested their applicability only in females. Moreover, the direct observation on the participants provided the exact data which increased the generalisability of the study. The photographic method depends on the usability of different software, constant power backup, expensive camera or digital hardware for high-resolution images, and trained personnel's for data interpretation. Direct measurements on participants although difficult, increases the feasibility even at medical colleges which lack a constant power supply.
Maisa worked on the Arabic population, attributed for detecting the reliability of neoclassical facial canons and calculated the NH of 54.12 mm in males and 53.19 in females. Karaca et al. worked extensively on the applicability of nasoaural canon in Turkish adults found NH 53.14 mm in males and 50.36 mm in females. He calculated EH as 61.49 mm and 58.81 mm in males and females, respectively. Antai reported the ratio of nasoaural canon as 0.8 in both genders. He evaluated nose height as 46.14 mm and 46.1 in males and females, respectively, whereas EH was 57.17 and 56.8 mm in males and females, respectively. The present study showed values of NH as 44.58 and 40.26 mm in males and females, respectively.
[Table 4] shows the comparison of applicability of the nasoaural canon and nasoaural inclination canon among different populations. The prevalence of the nasoaural facial canon was tested by Farkas et al. detected that 95.1% of participants followed the variation in which EH exceeded the NH (small canon) while only 4.9% of participants followed the valid nasoaural canon. Similarly, Porter and Olson did the anthropometric facial analysis of African-American women and observed the prevalence of the valid facial canon in 7.4% of the participants while 88% exhibited the variation in which EH was more than the NH (small canon) and 4.6% of the participants showed that the NH exceeded the EH (large canon). Barut and Aktunc also worked extensively with Caucasian primary school and university students to validate the prevalence of nasoaural facial canon. He identified that none of his participants had NH the same as EH and all the participants had EH more than NH.
Reliability of nasoaural canon was tested in the Turkish population by Karaca Saygili et al., who found it to be applicable in 4% of males and 1% of females, large canon applied to 6% and 3% of males and females, respectively, and small canon was followed by 90% and 96% of males and females. Antai also reported the deviation from the ideal nasoaural canon in the majority of Ibibios. They found valid canon in 2% of males and 4.5% of females, small canon in 92% of males and 93.5% of females, and large canon was applied to 6% of males and 2% of females. The present study also showed the occurrence of the valid nasoaural canon in 1% of the participant while 99% of participants followed the variation, i.e., EH > NH (small).
Nasoaural inclination canon was followed by 8.9% of North American Caucasian women in the study by Farkas et al., 3.7% of the African-American women studied by Porter and Olson, and 1% of the primary school pupils and university students in Bratilsalava studied by Barut and Aktunc, whereas the present study showed that 13% of the participants followed the valid inclination canon. 87 % deviated from the normal canon in which the nasofacial angle was more than the EA in the present study against the observation of 91.1% by Farkas et al., 96.3% by Porter and Olson, and 99% by Cvicelova et al.,,
Facial dimensions aid in the preoperative planning of patients with congenital conditions such as microtia and trauma of the ear or nose. Apt surgical forecast for esthetic facial reconstructive or corrective surgeries entails the surgeon not only a thorough knowledge of existing procedures but also an insight of how and when to employ those procedures. Hence, an exact facial examination becomes elemental. This study is an endeavor to portray the factors of such an analysis.
| Conclusions|| |
These results chip into the model of esthetics for people of Indian ethnicity, facial splendor seems to be an incorporation of inherent ethnic features with existing social and cultural features and esthetic yardsticks. The nasoaural facial canon and inclination canon is used in reconstructive surgeries by maxillofacial surgeons, plastic surgeons, and otolaryngologists. The values and validity of these canons in the Indian scenario will be fruitful for them during the surgeries. The ideal neoclassical canons did not seem to apply to our sample when measurements were implemented. Therefore, these cannot prove a useful basis of modus operandi in achieving esthetic goals for reconstructive surgeries in posttraumatic patients or cases of congenital deformities. A correlation was established between the ear height and nose height which could be used during reconstructive surgeries in local scenarios.
While considering ethnicity during facial reconstructive surgeries, parameters evaluated in the study may be of value. The NFA and EA proportions and ratio between the nose height and ear height elucidated in the present study may be useful in planning rhinoplasty, reconstructive surgery, prosthesis fashioning, and forensic medicine in the Indian population.
Limitation of the study
The shortcoming of the study was the small sample size. The EH of Indian females may give a slight erroneous reading as their ears are pierced and lobules are slightly elongated due to the earrings or ear pins. Furthermore, this was an anthropometric study using certain reference points. As the photographic method is not used, the position of the head in relation to Frankfurt's plane and vertical planes is not completely established in every case. A single observer conducted the measurements and so the systematic errors are nullified.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]