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ORIGINAL ARTICLE
Year : 2012  |  Volume : 18  |  Issue : 1  |  Page : 24-27

Demarking and identifying points-reliable criteria for determination of sex from external ear


Department of Anatomy, Goa Medical College, Bambolim, Goa, India

Date of Web Publication10-Jul-2012

Correspondence Address:
Prashant E Natekar
Department of Anatomy, Goa Medical College, Bambolim, Goa - 403202
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0971-7749.98292

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  Abstract 

Introduction: The anatomy of the external ear is clinically and surgically important as it is related to the vital structures in the neck. The morphometric measurements of the external ear were undertaken to determine the sex of an individual. These findings also suggest that this study will have a role in plastic and reconstructive surgery; identification of dysmorphic features in various chromosomal disorders. Aim: The present study will enlighten us to determine the sex from the external ear and provide an insight in determining the variations in sex from the external ear with 100% accuracy. It may also serve as a guideline before surgical intervention in otoplasty so as to resculpt or reshape the ear. Materials and Methods: The subjects were 100 healthy male and 100 healthy female medical students of age group 18-25 years of Goa Medical College, Bambolim, Goa, having no history of any diseases or other genetic disorder or heredity diseases. The anatomical landmarks used for this research study were the right and left a) ear length b) ear length above tragus c) ear length below tragus d) tragus length e) ear breadth f) concha length g) concha breadth h) lobule height i) lobule width of the external ear. Results: The measurement procedure proved to be easy and it did not show any discomfort to the participants. Ear length below tragus, lobule height and lobule width were larger in females than males. This method was made applicable to all the parameters except for ear length below tragus, lobule height and lobule widths since these parameters were greater in females than males. Conclusion: In this study, we could determine the sex from the external ear in a large percentage. The parameters were of little value when subjected to demarking point analyses. However, for a larger population the mean values for the above parameters from different regions will have significantly different values and hence, DPs are to be worked out separately for the different regions. These DPs are much simpler to apply than multivariate discriminant functional techniques for identification of sex with certainty.

Keywords: Concha, Demarking Points, External Ear, Lobule, Tragus


How to cite this article:
Natekar PE, De Souza FM. Demarking and identifying points-reliable criteria for determination of sex from external ear. Indian J Otol 2012;18:24-7

How to cite this URL:
Natekar PE, De Souza FM. Demarking and identifying points-reliable criteria for determination of sex from external ear. Indian J Otol [serial online] 2012 [cited 2019 Apr 22];18:24-7. Available from: http://www.indianjotol.org/text.asp?2012/18/1/24/98292


  Introduction Top


The human ear is the most defining feature of the face. The human auricle has a complex shape and yet the basic component of the normal structure of auricle is constant among the individuals. It is well known that the human bones are of great importance in providing us the skeletal differences between the sexes for anthropological and medico legal purpose. Several studies have been attempted to identify the sex from hip bones. [1],[2],[3] Studies on various bones like clavicle [4] humerus, [5] radius, [6] ulna, [7] femur, [8] tibia, [9] and fibula [10] have been identified with 100% accuracy.

From the aesthetic vantage point, the auricle usually is inconspicuous and is often taken for granted unless it is unduly prominent or deformed. The ear that sticks out too much is often the focus of ridicule wherein the people stare at the deformity. Physicians have used the auricle as a harbinger of underlying pathology, psychologists as a clue of personality disorder, criminologists as a means of racial discrimination. The anatomy of the external ear has been described in many texts, [11],[12],[13] yet the information about the differences between males and females has been lacking, which is essential for the plastic and reconstructive surgery [14],[15],[16],[17],[18] and also for medico legal importance. However, no studies are being carried out regarding the sexing of the external ear, though, various metrical parameters of the external ear have been evaluated. [19]


  Objectives Top


The main objective of this present study is to enlighten us and provide an insight in determining the variations in sex from the external ear with 100% accuracy.


  Materials and Methods Top


This study was carried out in 100 healthy male and 100 healthy female medical students of age group 18-25 (mean age 22 years) of Goa Medical College, Bambolim, Goa, having no history of any diseases or other genetic disorder or heredity diseases. Informed consent of the students was obtained. The measurements of the following parameters were as evolved by Natekar and De Souza (2006) measured in millimeters with digital vernier caliper of japanese company Mitutoyo with an accuracy of 1/10 mm. Least count of vernier caliper = 0.05 mm. The parameters shown in [Figure 1] are as follows:
Figure 1: External ear showing all the parameters of left side

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  1. Ear length: Uppermost of pinna to the lowermost point of lobule (L1-L2)
  2. Ear length above tragus: Uppermost point of pinna to tragion (L3-L4)
  3. Ear length below tragus: From intertragic incisure to the lower most point of lobule (L5-L6)
  4. Tragus length: From tragion to intertragic incisure (L7-L8)
  5. Ear breadth: From root of the ear to maximum convexity of the helix (L10-L9)
  6. Concha length: From cymba concha to intertragic incisure (L11-L12)
  7. Concha breadth: Posterior margin of the tragus to the maximum concavity of the antihelix (L13-L14)
  8. Lobule height: From lower point of attachment of the external ear to the head (otobasion inferior) to the caudal extension of the ear lobe free margin (subaurale) (L15-L16)
  9. Lobule width: From the most caudal attachment of the ear lobule to the head and to the outermost maximum transverse width of the ear lobule (L17-L18)
In the present study, each of the above parameter range from mean, standard deviation and identification points (IPs) were calculated in millimeters.

Identification points (IPs): The range of the male and female external ear for each parameter overlaps, the end points (limiting points) of the overlapping regions are "Identification Points."

Calculated range: The mean + 3 Standard deviation (SD) will determine the range of the above parameters. [20]

Demarking points (DPs): The limiting points determined on the basis of calculated range, are the "Demarking Points." [21]


  Observation and Results Top


It has been observed from [Table 1] that when all the parameters were statistically analyzed to find the range, mean and standard deviation, most of the parameters were larger in males as compared to females. However, ear length below tragus, lobule height and lobule width were larger in females than males which were also statistically significant. It was also observed that in most of the parameters which were statistically significant when subjected to identification point analysis for sex determination, they showed a high percentage of differences between males and females. As seen in [Table 2], the ear length (right) of males was in the range of 61.52-62.77, while that of females (right) was 58.01-59.32. No male ear length (right) was less than 59.32 and no female ear length (right) was less than 61.52. Therefore, 59.32 served as an identification point (IP) for males and 61.52 served as an I.P. for females. However, ear lengths between 59.32 and 61.52 are not sexed. This similar method was made applicable to all the parameters in [Table 1] except ear length below tragus, lobule height and lobule width where the DPs were reversed since the female parameters were greater than the males.
Table 1: Range, Mean, SD and IP of the various parameters of the external ear in millimeters

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Table 2: Demarking points for the various parameters of the external ear in millimeters

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In [Table 2], the calculated range was obtained using the formula mean + 3 SD. All the parameters except ear length below tragus, lobule height and lobule width (left and right) were larger in males than females. As seen in [Table 2], the calculated range (mean + 3 SD) of ear length (right) of males was 52.55-71.75, while that of female (right) was 48.67-68.66. No male ear length (right) was less than 52.55 and no female ear length (right) was greater than 68.66. Therefore, 68.66 served as demarking point (DP) for males and 52.55 served as a demarking point for females. However, ear lengths between 52.55 and 68.66 could not be sexed. This method was made applicable to all the parameters except for ear length below tragus, lobule height and lobule widths since these parameters were greater in females than in males and the DPs were reversed.


  Discussion Top


Ear sticks out from the head but when it excessively protrudes it is quite ridiculous. Children are usually nicknamed as "Dumbo" or "Mickey mouse". The Chinese believe that long ears predict longevity. [22]

Determination of sex of an individual based on human skeleton is well established. However, no data is available for identification of sex from the external ear. In our present study by IP analysis as seen in [Table 1], it has been observed that we could determine the sex from the external ear in a large percentage, since the overlapping range where the sex could not be determined was small. However, in [Table 2], it has been observed that all the parameters were of little value when subjected to demarking point analyses, since the percentage of ears identified by the demarking point analyses is low. This might be due to the fact that the overlapping data was larger between the two sexes. This analysis by limiting points holds good only for that particular sample and may not provide correct identification of the sex when applied to some other unknown sample of the same area, population or race. The reason for this may be that the biological variables may show vide variations, which the limiting points may not cover even if the sample size is large. In order to overcome this problem 3 SD were added and subtracted to the mean value (+ 3 SD) which will provide us the range of 99.75% of population of that area. Although our data reveals that the identification of sex from external ear by DPs was less in number, it was 100% accurate. The demarking point analyses have an advantage that it is not necessary that all the parameters of the external ear should cross the DPs before the sex can be identified. However if a single parameter crosses the DP it means that the sex can be identified with 100% accuracy.

 
  References Top

1.Pal GP, Bose S, Choudhary S. Reliability of criteria used for sexing of hip bones. J Anat Soc India 2004;53:58-60.  Back to cited text no. 1
    
2.Derry De. On sexual and racial characters of human ilium. J Anat 1923;58:71-83.  Back to cited text no. 2
[PUBMED]  [FULLTEXT]  
3.Washburn SL. Sex differences in pubic bone of Bantu and Bushman. Am J Phys Anthropol 1949;7:425-32.  Back to cited text no. 3
[PUBMED]    
4.Singh S, Gangrade KC. The sexing of adult clavicle-verification and applicability of the demarking points. J Indian Acad Forensic Sci 1968;7:20-30.  Back to cited text no. 4
    
5.Singh S, Singh SP. Identification of sex from humerus. Indian J Med Res 1972;60:1061-6.  Back to cited text no. 5
    
6.Singh G, Singh S, Singh SP. Identification of sex from radius. J Indian Acad Forensic Sci 1974;13:10-6.  Back to cited text no. 6
    
7.Singh G, Singh S, Singh SP. Identification of sex from ulna. Indian J Med Res 1974b;62:731-5.  Back to cited text no. 7
    
8.Singh S, Singh SP. The sexing of adult femora-Demarking points for Varanasi zone. J Indian Acad Forensic Sci 1972;11:1-6.  Back to cited text no. 8
    
9.Singh G, Singh S, Singh SP. Identification of sex from tibia. J Anat Soc 1975;24:20-4.  Back to cited text no. 9
    
10.Singh G, Singh S, Singh SP. Identification of sex from fibula. J Indian Acad Forensic Sci 1976;15:29-34.  Back to cited text no. 10
    
11.Snell R. Clinical Anatomy. In Snell R, editor. 7 th ed. Philadelphia: Lippincott Williams and Wilkins. 2004. p. 834-5.  Back to cited text no. 11
    
12.Standring S. The Anatomical Basis of Clinical Practice. In: Standring S, editor. 39 th ed. London: Churchill Livingstone; 2005. p. 649-50.  Back to cited text no. 12
    
13.Moore K, Dally A. Clinically Oriented Anatomy. In: Moore K, Dally A, editor. 5 th ed. Philadelphia: Lippincott Williams and Wilkins; 2006. p. 1022-3.  Back to cited text no. 13
    
14.Farkas LG. Anthropometry of the normal and defective ear. Clin Plast Surg 1990;17:213-21.  Back to cited text no. 14
    
15.Brent B. Auricular repair with autogenous rib cartilage grafts: Two decades of experience with 600 cases. Plast Reconstr Surg 1992;90:355-74; discussion 375-6.  Back to cited text no. 15
    
16.Brent B. Technical advances in ear reconstruction with autogenous rib cartilage grafts: Personal experience with 1200 cases. Plast Reconstr Surg 1999;104:319-34.  Back to cited text no. 16
    
17.Skiles MS, Randall P. The aesthetics of ear placement: An experimental study. Plast Reconstr Surg 1983;72:133-40.  Back to cited text no. 17
    
18.Brucker M, Patel J, Sullivan P. A morphometric study of external ear. Age and sex related differences. Plast Reconstr Surg 2003;112:647-52.  Back to cited text no. 18
    
19.Natekar PE, De Souza FM. A morphometric study of the normal human external ear and its clinical applications. Indian J Otol 2006;12:9-12.  Back to cited text no. 19
    
20.Rao CR. Advanced statistical methods in biometric research. London: John Wiley; 1962. p. 291-6.  Back to cited text no. 20
    
21.Jit I, Singh S. Sexing of adult clavicles. Indian J Med Res 1966;54:551-71.  Back to cited text no. 21
    
22.Khaw KT. Why do old men have big ears? The Chinese believe that long ears predict longevity. BMJ 1996;312:582.  Back to cited text no. 22
    


    Figures

  [Figure 1]
 
 
    Tables

  [Table 1], [Table 2]


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