Rajiv Gandhi University of Health Sciences
Karnataka, Bangalore
Annexure 2
Proforma for registration of subjects for dissertation
1 .Name of the candidate and Address:
Aaron David Kotturan
Postgraduate student, Department of Anatomy
St. John’s Medical College, Bangalore- 560 034.
Residential address:
Kotturan House, Behind Seeco, Manthripuram,
Irinjalakuda, Thrissur, Kerala, Pin-680121
2. Name of the institution: St. John’s Medical College,
Bangalore - 560 034.
3. Course of the study and subject: M.D (Anatomy)
4. Date of admission: 21th March 2011
“Morphometry of the external ear in an urban cosmopolitan Bangalore population using digital photography”5. Title of the topic:
6.1 Need for the study
The ear is an important component of the facial complex, which gives an impression of its bearer’s age and sex. Its size, shape and spatial location on the face are important from an aesthetic point of view. Any abnormality is an indication of a possible anomaly in the subject.1Anomalies of the ear such as lobule ptosis, missing external ear, prominent ears, and microtia may result from trauma, surgical resection, tumours, or congenital deformities.2 Surgical Correction of the anomalies are required also for psychological stability of the subjects. Some studies of the ear involving various syndromes and anomalies such as microtia have been published, but few studies have investigated the ear in the normal population.
Over the recent past, various studies have been conducted on morphometry of the external ear from different parts of the world. All these studies have shown that there is a high degree of variability in most of the measurements. These studies prove that much variability exists depending on the age, sex, ethnic group and even in the same person between the right and left ears. Auricular appearance and symmetry contribute enormously to the facial aesthesis. Any auricular defect in the form of disproportionate size, abnormal elongation of the auricular lobe, or a missing part is corrected by surgery. Cosmetic surgery and facial rejuvenation have become quite popular not only in the West, but also in many developing countries including India. For rectifying such abnormalities, a plastic surgeon requires information about normal auricular dimensions, the auricle’s bilateral position on the face, and general conformation. But these auricular data vary in different ethnic groups1.So the morphometric measurements given in the Western literature are less likely to be of much use in the Indian population. Thus knowledge concerning the anatomy of the normal ear in the Indian population is important to the plastic surgeon working here for planning treatment of ear deformities, designing prosthesis, manufacturing ear microphone.
Two advantages of the knowledge of auricle protrusion have been mentioned in Puma Purkait’s study of anthropometry of the normal human auricle in Indian males. First is that it an offer possible indication of a prominent ear when the superaurale distance from scalp is greater than 20mm. It’s incidence in the general population, ranges from 5.5% to 38.7%. Secondly, measurements of auricular protrusions are also found useful in designing of hearing aid instruments1.
The ear lobule morphometery gives information on age and sex and plays a valuable role in forensic investigation. Initially ear lobule parameters were studied for the surgical treatment of congenital deformities and reconstruction4. Now the ear lobules are also used in otomorphology for identification. Age dependent changes in lobules and its influence on individual identification through photographs or ear prints is of significance in forensic medicine and criminology5.
Knowledge of normal ear dimensions may be useful as a guideline for the plastic surgeon rectifying possible defects, for the forensic specialist in identifying a person and also for the manufacturer in making ear prosthesis. The dimensions vary in different ethnic groups, which necessitate them to base their observations on the data specific to the ethnic group.1Initiating a step in this direction, the current study attempts to furnish data for normal males and females from south India, which forms a major part of the Indian subcontinent.
6.2 AIMS AND OBJECTIVES:
The aims and objectives of this study are the following
1. To estimate the following quantitative parameters of the external ear
a) Total ear height
b) Total ear width
c) Lobular height
d) Lobular width
e) Distance from tragus to antihelix
f) Distance from tragus to helix
j) Ear projection
k) Auricular index : The width of the auricle X 100 / length of the auricle
l) Lobular index : The lobular width X 100 / lobular length
m) Conchal index : The conchal width X 100 / conchal length
2. To estimate the prevalence of the types of lobule in the external ear
3. To estimate the difference in quantitative parameters of the external ear between the male and female gender
4. To estimate the difference in quantitative parameters between the right and left ear in each gender
6.3 REVIEW OF LITERATURE:
The External Ear consists of the auricle or pinna, and the external acoustic meatus. The auricle projects to a variable and individual degree from the side of the head and collects sound waves, which it conducts along the external auditory canal inwards to the eardrum, the tympanic membrane. The external ear is composed of three primary components: the helix-antihelical complex, the conchal complex, and the lobe.6 Ito I et al in his study shows that the age and sex of an individual could be estimated from morphometric measurements of the external ear. It is also known that the size of the human auricle increases after completion of development which occurs by teenage.7
There are many studies of ear morphometry in the literature. The shape, size and orientation of each pinna is as individual as a fingerprint but it is possible to make some generalisations; men have larger ears than women, ears increase in both length and width with increasing age, and overall ear size differs according to ethnic group.8
In Ruma Purkait et al Study on the Anthropometry of the Normal Human Auricle done on 415 Adult Indian Men, all the linear measurements showed a steady increase in size with age. The measurements of the lobule were found to depend on the shape and attachment to the cheek. Mean lobular and auricular indices decreased with increasing age. It was also found in the above study that Indian males have smaller auricular and lobular length compared with other ethnic groups.1
M.Gulhal Bozkir et al observed in 341 healthy young Turkish adults,a significant difference in the total ear height in comparison to Japanese population. In the above study it was also shown that the total ear height and ear width were longer in males within the Turkish population.9
Morphometric study of the human ear by K.Skaria Alexander et al, demonstrated through 420 volunteers that ethnically Indian volunteers had largest ears followed by Caucasians and Afro-Caribeans. His study also showed that the size of the ear keeps increasing with age3
A study on the Age and Sex related changes in the normal human ear by Chiarella Sforza,Gaia Grandi et al analysed the three dimensional coordinates of several soft-tissue landmarks on the ears obtained by non invasive computerized electromagnetic digitizer in 497 males and 346 females who were healthy. All ear dimensions were significantly larger in males than in females. Significantly larger values were found in older individuals. Width to length ratio and sagittal angle of auricle were found to be significantly decreasing with age but not related to the gender of volunteers.10
Studies on the external ear have been done through various modalities such as digital calliper, photocopier scanning and digital photography. A study was done by Bor-Shong Liu et al, to compare the reliability of measurements obtained by electronic digital calliper, photocopier scanning and digital photographic methods. It revealed that there is no significant difference in length and width of the pinna between the three methods.11
An Anthropometric study on the normal human auricle in Japan was conducted by Itoh I, Ikeda M et al. Study was done on 1958 healthy Japanese people with no disease, 966 males and 992 females of the age range 0-99years.They were classified at 5year intervals into 18 groups and each group had about 50 to 72 persons. Larger values were obtained for males than females in almost all age groups. Rapid growth was observed until late teenage and significant growth continued thereafter until advanced age. It concluded that the change in , however age associated changes appear to continue during adulthood.7
A study by Anu Sharma et al done on 160 ear lobules of 80 individuals of age range 1 to 20 years showed that there is an increase in linear dimensions with age. It also showed that in comparison to Caucasian and Japanese populations Indian population had lesser measurements. The lobule also showed to be predominantly of the square variety.12
Morphometric study on the ear lobule done by Anshu Sharma et al showed that length of the lobule showed significant increase in growth with age. Breadth and thickness of the ear lobule also increased with age. North Western Indian population were found to have smaller ear lobule than Japanese or Caucasians. The attached or square type of lobule was the most common, followed by free or pendulous type and then the tapering type.13
In the study conducted by Cagatay Barut et al, anthropometric measurements of the external ear were taken from 153 primary school children in Turkey.The left ear indices were found to be significantly higher the right ear indices for all the subjects.21.6% of all the patients had attached lobules.14
Azaria R et al had done a study on morphometry of the adult human lobe in 547 subjects. Analysis of variance for ethnic origin and skin colour revealed a longer left earlobe in Ashkenazi and Sephardic Jews compared with Ethiopian, Asian and American Jews and Arabs and a short earlobe in blacks compared with dark and fair skinned people. On multiple regression analysis of the above study it was found that sex and age were the only factors that contributed to earlobe length.15
Through this present study morphometric data of an urban cosmopolitan Bangalore population will be obtained and analysed.
7 MATERIAL AND METHODS
7.1 SOURCE OF DATA: Students and Staff of St John’s National Academy of Health Science, Bangalore.
SAMPLE SIZE: A total of 200 individuals, consisting of 100 males and 100 females. Sample size got using N master , through single mean hypothesis testing – one population mean, with an alfa error fixed at 5 and power fixed at 80 %.
7.2 INCLUSION CRITERIA: Individual coming within the age group of 18 to 30 years in St John’s National Academy of Health Science, Bangalore
7.3 EXCLUSION CRITERIA: Individuals whose normal external ear morphology has been altered by trauma, accidents or surgery. Those below 18years or above 30years of age.
7.4 STUDY DESIGN: Descriptive study- cross sectional type
7.5 PROTOCOL OF THE PROCEDURE:
1) Lateral surface of Auricle photographed
· Subject is seated comfortably and both the camera lens and photographer aligned and parallel to the subject
· Mid vertical grid line of camera aligned to pass through the mid-sagittal plane of face, while the mid horizontal passed through the Frankfurt horizontal plane.
· Ear features are then captured using a digital camera mounted on stand and maintaining a distance of 90cm between the subject and the lens.
· Digital images are transferred to a computer and the images will be analysed with Adobe Photoshop software (version 7.0). Here first the various soft tissue landmarks are tagged on the photo. The land marks of the auricle are-
1. Superaurale
2. Subaurale
3. Preaurale
4. Postaurale
5. Concha superior
6. Incisura intertragica inferior
7. Incisura anterior auris posterior
8. The strongest antihelical curvature
9. Lobule anterior
10. Lobule posterior
Then the various tagged points are connected on the photo to bring about relevant lines on the image. The lines are then measured
2) Posterior View of Auricle is photographed
· Subject seated comfortably with both camera lens and photographer aligned and parallel but posterior to the subject.
· Mid vertical grid line of the camera viewfinder is aligned to pass through the base of the auricle coming in contact with the mastoid prominence, while the mid horizontal passes through the tragal level
· Ear features on the posterior aspect are then captured using the digital camera mounted on stand and maintaining a distance of 90cm between the subject and the lens.
· Digital images are transferred to a computer and the images will be analysed with Adobe photoshop software (version 7.0) by first marking the various soft tissue landmarks on the photo and drawing relevant lines on the images
· Measurements of these lines are taken.
3) Statistically analysis – All measurements were tabulated and separated based on gender and age. Data was analysed using SPSS version 16 in the following manner
Objective No: / Descriptive Statistics, Statistical Model / Inferential statistics1 / Mean, Standard deviation, & 95% Confidence interval / One sample T test
2 / Incidence, 95% Confidence interval / One sample T test
3 / Difference in Mean, 95% Confidence interval of the difference in mean. / Independent sample T test
4 / Difference in Mean, 95%Confidence interval of the difference in mean. / Paired T test
7.6 Does the study require any investigations or interventions to be conducted on patients or other human or animals? If so please describe briefly
No interventions or investigations will be done. Only digital photography will be taken. This causes no harm to the subjects. The photographs will be used for research purpose only.
7.7 Has ethical clearance obtained from your institution in case of 7.3?
The study has been submitted for ethical approval
APPENDIX I
DD / MM / YYYYINI / TIA / LS
CONSENT FORM
STUDY TITLE
“MORPHOMETRY OF THE EXTERNAL EAR IN AN URBAN COSMOPOLITAN BANGALORE POPULATION USING DIGITAL PHOTOGRAPHY”
I have been explained the procedures involved in the study and I have understood that:
1. Personal and medical history will be collected as a part of the study.
2. Digital photographs of my external ear will be taken from different angles if required.