THE NASAL INDEX OF SOUTH INDIAN SKULLS

Nurul Syamimi binti Mohd Azlan Sunil 1 and K. Yuvaraj Babu 2 . 1. Bachelor of Dental Surgery Saveetha Dental College, Chennai-600077. 2. Assistant Professor, Saveetha Dental College and Hospitals, No.162, PH road, Chennai-600077. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History

The nose is a part of the respiratory tract and it is located superior to the hard palate [1]. The anterior nasal aperture is pear-shaped, being wide below and narrow above.The nose is considered as one of the clues that provides information to the racial origin [2]. Environmental climatic conditions and race are variables that determines the shape of the nose [3]. For example, in the cold climate, smaller, narrower nose is favoured and dry atmosphere favours a more extensive nose in hotter atmosphere [4].This is to say that nasal prolongation is impacted by adjustment to environment [5].
Nasal index prove as a useful tool for neurosurgeon, plastic surgeon and anthropologists. Facial anthropometry is an important tool utilized as a part of genetic counselling, reconstructive surgery and forensic examination [6]. Before changing the state of the nose, analysis of the nasal index is the initial step a specialist takes before performing rhinoplasty.
The nasal cavity is usually classified into three major groups of nasal parameters [7] All races have their quirks and these differ considerably when alluding to different anthropometric parameters [9].Nasal index is very useful in anthropology in differentiating racial and ethnic differences [12][13] [14].Nasal index has got a variation in gender, age and race. There is a need to analyse and find out the nasal index for South Indian population.

Materials and Method:-
Fifty South Indian dry skullsof unknown sex wererandomly selected from Department of Anatomy of Saveetha Dental College, Chennai. Skulls with congenital abnormalities and damaged anterior nasal aperture were excluded. A sliding vernier calliper (12.5cm with accuracy of 0.01cm) was used to measure the nasal height and nasal width, which is shown in Figure 1.The nasal width was measured first.The distance of the widest extension was taken as the nasal width. Next, the nasal height was measured from the lower border of nasal bone tothe anterior nasal spine, perpendicular to that of the nasal width [11]. The measurements were tabulated and results were calculated.

Result:-
The result of the study were presented in tabular form. The dimensions of the nasal parameter that has been acquired in the study, together with the statically analysed values of skulls are shown in Table 1.The height of the dry skulls range from 2.0cm to 3.6cm, the width is from 2.5cm to 4.0cm and the nasal index of the dry skulls range from 57.1 to 116.1cm. The mean nasal height, nasal width and nasal index are 3.26cm, 2.49cm and 77.3cm respectively.

Discussion:-
A study was carried out in 1980 that showed most Western European possess leptorrhine type of nose, which is long and narrow with nasal index of 69.9 or less. Australians as well as the Bantus and Bushmen of African were platyrrhine, having broad nose with a nasal index of 85.0 and above 26. Similar to that of the general Western Europeans, a past study has shown that the nasal index of Germans are an average of 71.0 and below, which is leptorrhines [10]. Table 2 shows the comparison of nasal indices that has been acquired in the study with previously studied nasal indices of other populations. Table 2 clearly shows that ethnicity significantly affects nasal parameters as differences exist amongst different races/ tribes and ethnic groups as shown in the table. Australoids are platyrrhine with broad nose and have nasal index of 85, most Caucasians are leptorrhine with long and narrow nose and have nasal index of 69.9 or mesorrhine with index between 70.0 and 84.9 [15]. The Indo-Aryan is similar to the Europeans, possessing a fine nose [15] In Jingpo people in China are mesorrhine [16]. Indo-African [15] and AfroAmerican have platyrrhine nose type [17]. This study has shown that the South Indians have a mesorrhine nose type, similar to the Aryans, Germans, Onges and Yoruba females, with nasal index of 77.3.

Conclusion:-
The mean nasal index of South Indian population has been determined. The South Indian fall within the mesorrhine or medium nose type. The result of this study will be useful in forensic medicine and anthropology and will also serve as a future framework for estimating the other craniofacial variables in same population.