Morphological variations and biometrics of ear: First documented evidence from ethnic Kashmiri Population (Northern India)

Shah Sumaya Jan; Sobiya; Bashir Ahmad Shah; Sheikh Mohd Saleem

doi:10.4103/cmi.cmi_89_22

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ORIGINAL ARTICLE

Year : 2023 | Volume : 21 | Issue : 2 | Page : 88-92

Morphological variations and biometrics of ear: First documented evidence from ethnic Kashmiri Population (Northern India)

Shah Sumaya Jan¹, Sobiya¹, Bashir Ahmad Shah¹, Sheikh Mohd Saleem²
¹ Department of Anatomy, Government Medical College, Srinagar, Jammu and Kashmir, India
² Independent Public Health Consultant, New Delhi, India

Date of Submission	15-Aug-2022
Date of Decision	10-Nov-2022
Date of Acceptance	19-Nov-2022
Date of Web Publication	07-Apr-2023

Correspondence Address:
Dr. Shah Sumaya Jan
Department of Anatomy, Government Medical College, Srinagar, Jammu and Kashmir
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/cmi.cmi_89_22

Abstract

Background: Anthropometric data for a specific population is always required for identification, product design, ear reconstruction, and manufacture of ear-related instruments. This study aimed to determine the anthropometric measures of the external ear and compare them on both the sides and in either sex among the ethnic Kashmiri population. Methods: The study sample had 98 boys and 102 females aged 18–25. Subjects with a history of craniofacial trauma, ear diseases, congenital defects, or ear surgery were excluded from the study after racial confirmation. A single investigator took all measurements on both the ears using a standard digital Vernier's caliper capable of measuring to the nearest 0.1 mm. Results: It is observed that the total ear width (EW) in the right ear ranged from 2.92 ± 0.19 to 3.12 ± 0.22 in cm. The mean EW on the left ear was found more significant than on the right side in the studied population. The mean TEH among the males in the right ear was found to be 6.02 ± 0.34, while in the left, it was 5.78 ± 0.33. Furthermore, the mean EW among the females on the right side was 2.88 ± 0.21 compared to 2.85 ± 1.25 for the left and right ears respectively. The association was found to be significant (P ≤ 0.001). Conclusion: Identifying landmark variations in distinct ethnic groups could help establish morphological assessment and morphometric variations of human ears.

Keywords: Ear, ear deformities, ear measurements, racial groups

How to cite this article:
Jan SS, Sobiya, Shah BA, Saleem SM. Morphological variations and biometrics of ear: First documented evidence from ethnic Kashmiri Population (Northern India). Curr Med Issues 2023;21:88-92

How to cite this URL:
Jan SS, Sobiya, Shah BA, Saleem SM. Morphological variations and biometrics of ear: First documented evidence from ethnic Kashmiri Population (Northern India). Curr Med Issues [serial online] 2023 [cited 2023 Jun 4];21:88-92. Available from: https://www.cmijournal.org/text.asp?2023/21/2/88/373762

Introduction

The ear has been used as a measure for human identification since the late nineteenth century when Alphonse Bertillon used it as one of eleven anthropometric measures for his manual system of identifying persons.^[1] The ear has a single piece of fibrocartilage with a convoluted relief on the anterior, concave side, and a relatively smooth structure on the posterior, convex side. The development of the ear begins early after conception, and by the 38^th day, some of its characteristics are discernible. On the 56^th day, the ear shifts to its final position and the form of the ear may be identified on the 70^th day. The shape is, therefore, permanent and never changes from birth to death.^[2] The human ear is divided into three sections: the external, middle, and internal ear. The external ear, which consists of the auricle and the external auditory meatus, is employed in forensic science to identify and authenticate individuals. Furthermore, the auricle is one of the five basic features of the human face and has a considerable influence on its appearance.^[3] The auricle's lateral side is irregularly concave, with several eminences and depressions that can make contact with varied surfaces and form a rubber stamp-like print. Ear prints are frequently seen on surfaces where someone has been listening to determine whether or not the place is occupied during a crime. This frequently occurs near doors or windows.^[4] Ear biometrics is an interesting subject since ear marks and measurements are routinely used for identification during crime scene investigations in the absence of legitimate fingerprints. Ear biometrics may positively identify a person by comparing the human ear and its structure. The size of the pinna has been shown to vary amongst ethnic groups.^[5] Many different studies on the morphological variations of human ears have been conducted. Nonetheless, evidence on differences across interethnic groups is limited, which is crucial for individual identification in forensic sciences.^[6],[7] Each external ear's form, size, and orientation are as unique as a fingerprint, yet it is possible to draw certain conclusions: For example, males are known to have larger ears than females. Anthropometric data for a specific population is always required for identification, product design, ear reconstruction, and ear-related instruments. The current study aims to give anthropometric data for the ear in the ethnic Kashmiri population. The purpose of this study was to identify the typical anthropometric measures of the external ear in boys and girls, as well as to compare them on each side and in either sex. The finding will help surgeons for better instrumentation during surgeries.

Methods

Study design

Cross-sectional study.

Setting

The study was conducted at the Postgraduate Department of Anatomy, Government Medical College, Srinagar, Jammu and Kashmir, India, a tertiary care teaching hospital, between March 2019 and May 2020.

Participants

The study sample comprised 98 boys and 102 females aged 18–25. After racial confirmation, using college IDs, all individuals were instructed and explained the study's aims, and signed informed consent was taken from them. For the purpose of this study, the term “ethnic” has been used which is defined as “relating or belonging to a group of people who can be seen as distinct (= different) because they have a shared culture, tradition, language, history, etc.”(Cambridge dictionary) The institutional ethics committee approved the study proposal vide order no. IRB PMD831/02/2019.

Clinical and demographic data

The study excluded those with a history of craniofacial trauma, ear diseases, congenital defects, or ear surgery. The anatomical landmarks used for ear biometrics of both the sides were mentioned as under [Figure 1].

Figure 1: Landmarks used for the ear morphology.

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Supernatural (sa) – Highest/superior most point on the free margin of the auricle
Subdural (SBA) – Lowest point on the free margin of the ear lobe
Preaurale (pra) – Most anterior point of the ear, located just in front of the helix
Postaurale (pa) – Most posterior point on the free margin of the ear (helix)
Inferior most attachment of pinna
Deepest point on the intertragic notch
Posterior most point of the ear lobe

All measurements on both the ears were obtained by a single investigator using a standard digital Vernier's caliper capable of measuring to the nearest 0.1 mm. To guarantee accuracy, measurements were collected twice for each subject, and the mean of the two measurements was chosen for each dimension. For each participant, ear index (EI) (ear width [EW]/ear height × 100) and lobule index (LI) (lobule width [LW]/lobule height [LH] × 100) were determined.^[8] Oval, rectangular, triangular, and round were the four primary ear morphological forms examined.^[1] Also noted was whether the ear lobule attachment was adherent or free.

Statistical analysis

The data was entered into a Microsoft Excel spreadsheet. The mean and standard deviation were used to summarize continuous variables. Percentages were used to summarize categorical variables. The Chi-square test was used to determine the independence of two category variables. P < 0.05 was considered statistically significant. All statistical analyses were done using BM Corp. Released 2020. IBM SPSS Statistics for Windows, Version 27.0. Armonk, NY, USA: IBM Corp.

Ethical issues

Prior to the start of the study, the Institutional Ethical Committee granted its clearance. The committee approved the same per the procedure stated in the proposal to vide no: IRB/MC dated February 9, 2019.

Results

In the current study, it was found that 80 (81.63%) men and 85 (83.33%) females had oval form, 12 males (12.24%) and 13 (12.74%) females had a round shape, and 7 (7.14%) male and 4 (3.92%) female have triangular shape (both on the right side and on the left side). Therefore, this form of morphology can be utilized to determine a person's identification.

The morphometric measurements of the external ear among different age groups (19–20 years, 21–22 years, 23–24 years) are illustrated in [Table 1]. It is observed that the total ear height (TEH) in the right ear ranged from 5.63 ± 0.32 to 5.98 ± 0.33, and in the left ear ranged from 5.65 ± 0.35 to 6.20 ± 0.24 in cm, respectively. It was observed that the mean TEH of the left ear was more significant than the right ear, especially in the 23–24 years' age group. The TEH serves as an essential characteristic in the evaluation of congenital anomalies. It is observed that the total EW in the right ear ranged from 2.92 ± 0.19 to 3.12 ± 0.21, and in the left ear ranged from 2.90 ± 0.24 to 3.12 ± 0.22 in cm, respectively. It was also observed that EW had greater values among those aged 23–24 years. In the case of LH, the right ear length in cm ranged from 1.60 ± 0.21 to 1.73 ± 0.26, while the left ear ranged from 1.65 ± 0.20 to 1.76 ± 0.28, respectively. The mean LH on the left ear was found to be more significant than on the right side in the studied population. Moreover, the LW on the right side ranged from 1.89 ± 0.15 to 1.99 ± 0.26, while on the left side, it ranged from 1.95 ± 0.21 to 1.98 ± 0.28 in cm, respectively.

Table 1: Morphometric measurements of external ear among different age groups

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The association of ear indices among both the genders in the current study is described in [Table 2] and [Table 3]. The mean TEH among the males in the right ear is 6.02 ± 0.34, while in the left is 6.03 ± 0.33. The mean TEH among the females on the right side is 5.78 ± 0.34, while on the left is 5.67 ± 0.35. The association was found to be significant (P ≤ 0.001). The mean EW among the males in the right ear is 3.01 ± 0.20, while on the left is 3.05 ± 0.24. The mean EW among the females on the right side is 2.88 ± 0.21, while on the left ear is 2.85 ± 0.25. The association was found to be significant (P ≤ 0.001). The mean LH among the males in the right ear is 1.65 ± 0.18, while on the left is 1.67 ± 0.20. The mean LH among the females on the right side is 1.65 ± 0.23, while on the left is 1.65 ± 0.21. The association was found to be insignificant. The mean LW among the males in the right ear is 1.98 ± 0.19, while on the left is 1.98 ± 0.22. The mean LW among the females on the right side is 1.93 ± 0.20, while on the left ear is 1.93 ± 0.20. The association was found to be insignificant. The mean EI among the males in the right ear is 51.11 ± 3.78, while in the left ear is 51.32 ± 3.82. The mean EI among the females on the right side is 50.26 ± 4.09, while on the left ear is 49.79 ± 4.74. The association was found to be insignificant. The mean LI among the males in the right ear is 120.02 ± 14.36, while on the left is 118.31 ± 16.78. The mean LI among the females on the right side is 117.33 ± 15.34, while on the left is 116.85 ± 15.03. The association was found to be insignificant.

Table 2: Association of morphometric measurements of external ear in male and females

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Table 3: Association of morphometric measurements of external ear in-between two genders

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Discussion

Knowledge of typical human ear measurements and physical features of various groups can be beneficial in the inclusion and exclusion of persons for identification based on ear variances acquired from offenders from an anthropological and forensic viewpoint. The current ear biometric study was conducted because the variation in shape, size, features, and the lack of impact of expression change on ears makes it a more useful biometric instrument in forensic sciences compared to the face. The measurements of the ears are also crucial in identifying congenital abnormalities, acquired deformities, syndromes, and treatment planning. The research might also help plastic surgeons recreate an anatomically accurate ear during the repair.

The TEH is used for evaluating congenital disabilities (such as trisomy 21), face reconstruction, and forensic applications. The ear reaches its mature height at 13 years in males and 12 years in females. The mean TEH was found to be higher in men (R: 6.02 ± 0.34, L: 6.03 ± 0.33) compared to women in the study population (R: 5.78 ± 0.34, L: 5.67 ± 0.35). Purkait^[9] also reported similar findings in his study Moreover, the findings were comparable to those of Bozkir et al., and Asai et al., who discovered that the TEH of the left ear in males was more significant than in females, respectively.^[10],[11] Males emit greater quantities of growth hormone than females throughout this age range, which validate the above findings.

Furthermore in both the groups, other anthropometric ear parameters (LH, LW, LI, EI) were also significantly greater in males than females. The results were consistent with those of Ekanem et al.^[8] and also comparable to other studies by Eboh DEO, and Deopa et al.^[12],[13]

Wang et al. discovered that men had longer and wider lobules than females in a study from Northern China.^[14] It has been suggested that after age 20, the size growth is primarily due to secondary elongation of the earlobes due to gravity. Auricular measures were shown to grow considerably with age in both the genders. This is due to alterations generated by a modification in the elastic fibers, which occur more quickly in males than females.^[15]

The comparison of biometric ear measurements of both the ears in the study group found that all values in the ethnic Kashmiri community were greater among males than females. The ethnic and genetic background differences support the findings, which are similar with the findings of other reported study.^[16]

Ferrario and his team discovered that males had considerably larger ear indices on both the sides than females.^[17] According to Barut and Aktunc, males exhibited insignificantly higher right ear indices and significantly higher left ear indices.^[18] The current study found a significant difference in ear height and width, LH and width between genders, even though left ear indices were more significant in males than the right ear and right ear indices among females were more significant than the left ear respectively.

Limitations of the current study

The study's limitations were a small sample size and a lack of age-related differences in ear biometrics between study groups.

Conclusion

The current study's morphological evaluation and morphometric variances of human ears can be used as forensic evidence by detecting landmark variations in different ethnic groups.

Acknowledgment

The authors warmly thank everyone who took part in this study. The findings of such studies have the potential to improve humankind's general understanding, which in turn can improve patient treatment. As a result, these individuals and their families deserve our heartfelt thanks. We would like to acknowledge the contributions of Dr Sheikh Mohd Saleem [Public Health Researcher] who assisted with the analysis, manuscript writing and overall guidance in preparation of this manuscript. There are no conflicts of interest.

Ethical statement

Before conducting the study, ethical clearance was taken from the Institutional Ethics Committee. During the study, informed consent was taken from the participants, and confidentialityin relation to their information was assured to the participants and was strictly maintained.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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