|Year : 2012 | Volume
| Issue : 3 | Page : 156-158
Nasal index and age estimation from nasal dimensions of Manipuri fetuses
Department of Anatomy, Regional Institute of Medical Sciences, Imphal, Manipur, India
|Date of Web Publication||10-Jun-2013|
Department of Anatomy, Regional Institute of Medical Sciences, Imphal, Manipur
Source of Support: None, Conflict of Interest: None
DOI: 10.4103/0972-4958 .113225
Aim: To determine the nasal indices of fetuses of Manipuri population in order to classify the nose type and to derive at a regression equation for determining gestational age from nasal dimensions. Materials and Methods: Sixty four Manipuri fetuses, between 12 weeks and 40 weeks of gestation were used. Nasal height and width were measured using vernier caliper. The data obtained were subjected to statistical analysis using descriptive statistics, Pearson correlation 'r', and linear regression model were used. Results: A statistically significant correlation between gestational age and nasal height (r = 0.89, P < 0.01) as well as nasal breadth (r = 0.85, P < 0.05) were observed. The nasal index of a Manipuri fetus at full-term was platyrrhine/chamaerhine. Conclusion: The nose of fetuses of Manipuri population at birth is platyrrhine which is round and wide. Its relevance may be found in forensic and clinical practice.
Keywords: Chamaerhine, Ethnicity, Fetus, Nasal indices
|How to cite this article:|
Rajlakshmi C. Nasal index and age estimation from nasal dimensions of Manipuri fetuses. J Med Soc 2012;26:156-8
| Introduction|| |
The human body dimensions are affected by geographical, racial, gender, and age factors. Physical measurements can be worked out and used in differentiation of racial phenotypes. Basically, there are 3 types of race - Caucasoid, Negroid, and Mongoloid. There are 3 types of nose as classified by anthropologists - leptorhine, mesorhine, chamaerhine. There are ample clinical reports on nose especially from aesthetic rhinoplasty point of view because of distinctive anatomical differences between non-Caucasian and the Caucasian nose. Reports on nasal index of fetus are however, few with no data on Manipuri population. Manipuris, the indigenous people of Manipur, comprises of the Meiteis and the Tribals, and both belong to Mongoloid race. Thus, the present study was aimed at documenting standard values of nasal height and width (nasal index) for fetuses of Manipuri population by anthropometric measurements and also at comparing the values with available data from other populations of the world for any ethnic or racial differences and additionally, to determine if there was correlation between nasal dimensions and gestational age.
| Materials and Methods|| |
The study was carried out in the Department of Anatomy, Regional Institute of Medical Sciences (RIMS) Imphal after approval from Ethical Committee of the Institute. Sixty four fetuses (12-40 weeks) devoid of gross anomalies were procured from the Department of Obstetrics and Gynecology, RIMS Hospital, Imphal with due permission from the concerned parties and authorities. Fetuses belonged to indigenous residents of Manipur. The fetuses were divided into 7 groups with age interval of 5 weeks each. Fetal age was based on crown-rump length and last menstrual period.
After proper preservation of the body in 10% formalin, dissection of head and face region were carried out to expose the nasal area and measurements were taken using Martin's sliding calipers. Following parameters were recorded:
Nose was categorized as Leptorhinae, Mesorhinae, Platyrrhine/Chamaerhinae.  Statistical analysis of data was performed by descriptive statistics like mean and standard deviation, Pearson correlation coefficient 'r', and linear regression model were used. P < 0.05 was taken as the significant level.
- Nasal height was measured from the nasion to the anterior nasal spine [Figure 1].
- Nasal width was measured as the maximum horizontal distance across the nasal aperture.
- Nasal index = nasal breadth/nasal height × 100.
| Observation|| |
A high correlation between gestational age and both nasal height (r = 0.89, P < 0.01) and width (r = 0.85, P < 0.05) was observed. Gestational age can be determined from nasal height by regression equation Y = 2.87 + 1.59 h, where Y and h denotes gestational age and fetal nasal height. This equation highlights that when nasal height increases by 1 mm, gestational age advances by 1.59 weeks. Regression equation for nasal width was also developed as Y = 5.53 + 2.43 w, where w represents nasal width. Growth spurts in both the nasal height and width was observed during the gestational age group 16-20 weeks, 24-28 weeks, and 36-40 weeks. Nasal index of Manipuri fetuses ranged between hyperchamaerhhine (very broad) during second trimester than gradually becomes chamaerhhine/platyrrhine (broad nose) by full-term.
| Discussion|| |
There are well documented differences in facial structures between ethnic groups. , Distinctive racial variations in midfacial profiles of Black and White fetus are established early in fetal development by 24 weeks and maintained postnatally. , The nose is relatively shorter and broader in Negro fetuses in all stages of development, causing a very marked difference in nasal index of Negroid from Caucasoid races.  However, they failed to classify the nose based on nasal index.
An ultrasonographic study revealed the variation in fetal nasal length among different race and ethnic groups and suggested the need for a race and ethnic-specific formulas for nasal bone length.  The present study compared two distinct racial population of Caucasoid from North Indian fetuses to the Manipuri fetuses, which belonged to Mongoloid race [Table 1]. It was observed that both the nasal width and height of Manipuri fetuses increased with gestational age which was statistically significant and this result was also observed in North-Indian fetuses. Interestingly, in both the racial group nasal height is a better predictor of fetal age as compared with nasal width because of the very slow growth rate of the nasal width.
|Table 1: Comparison of nasal dimensions and index between Mongoloid race (present study) and Caucasoid race (Tuli et al., 1995)|
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The nasal index of Manipuri fetuses at term is around 58 which are chamaerhhine whereas the North Indian fetuses are leptorhhine having a nasal index of 40. The study observed a significant correlation between nasal dimensions and gestational age of fetus, which was also observed in North Indian fetus.  Regression equation derived from the present study could be used to determine the age of a fetus of Manipuri population when the age of the fetus is doubtful in medicolegal cases.
Literatures on fetal nasal dysmorphism and its clinical significance are abundant. Nasal abnormality is one of the screening indexes of marker for detecting trisomies 13, 18, and 21.  Of late, nasal bone has been shown to be absent in 73% of fetuses with Down's syndrome in the first trimester, compared to 8.3% of control fetuses, suggesting this as a promising new sonographic marker.  There is no denying that nasal proportions do vary between ethnic groups in adult nose. However, there is no evidence of ethnic specific predilection to disease due to anatomical variation, physiological vulnerability or genetic susceptibility.  However, reports on age determination from nasal dimension is scarce and hence, it is speculated that the reference ranges and regression equation deducted from the present study could be a promising new marker to determine gestational age as well as to detect dysmorphism of nose. Thus, this could be useful for anthropologist, forensic experts or sonologists alike.
Anthropologists agree that variations in nasal index, the ratio of nasal breadth to nasal height variation are climate related. They feel that the variation in bony nasal cavity is due to man's adaptation to the environment. Furthermore, it was argued that nasal breadth contributes little to the worldwide variation in nasal index. This hypothesis was rejected following a study  wherein the nasal breadth and nasal height exhibit equivalent intrinsic variation among population. However, the study supported the adaptive role for human nasal index variation. It may be mentioned that the nasal cavity is essential for humidifying and warming the air before it reaches the sensitive lungs, a function carried out after birth. However, reports on ethnicity of nasal dimensions in fetus are meager. The present study not only brings forth a striking ethnicity in nasal dimension during fetal life but also derived at regression equations to determine fetal age from nasal dimensions. Therefore, the present study would include in the aforementioned hypothesis of nasal variation due to man's adaptation to environment, the role of ethnicity because of the presence of variation even during fetal life.
| Conclusion|| |
The study also brings forth a striking ethnicity in the nasal index of fetuses of Manipuri population wherein the nose becomes chamaerhine from 28 weeks of gestation onwards till term. The reference values deducted from the present study is presumed to be a promising new marker to detect dysmorphisms of nose by anthropologist, forensic experts or sonologists alike.
| Acknowledgment|| |
I wish to thank Prof. R. K. Narendra Singh, HOD of Biostatistics, RIMS for help in statistics.
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