Sexual Dimorphism from Cranial Capacity of Adult South India Skulls

 

Mohamad Qulam Zaki Bin Mohamad Rasidi¹, Dr. S. Saravana Kumar²

¹BDS, Saveetha Dental College and Hospital, Chennai, Tamilnadu, India

²Professor, Saveetha Dental College and Hospital, Chennai, Tamilnadu, India

 

ABSTRACT:

Aim and objectives: The aim of this study is to find out the correlation between the cranial capacity and the sexual dimorphism.

Materials and Methods: 38 dry human skulls originated from South India (20 males and 18 females) were obtained from the Department of Anatomy, Saveetha Dental College and Hospital, Chennai, Tamil Nadu, India, during the year of 2015. All the skulls used for this study are from the adult skulls which are approximately above 20 years.

Results: The mean capacity for male skulls is calculated to be 1030.05 ± 35.65 CC (range 963 CC - 1099 CC) and the mean capacity for female skulls is 850.24 ± 40.95 CC (range 757 CC - 890 CC). The South India Sexual Dimorphism Index based on the cranial capacity of skull is 17.46%.

Conclusion: The mean cranial capacity among the South India adult dry skulls reveal that male have higher values of cranial capacity compared to female.

 

 

INTRODUCTION:

The sex differentiation from a skull plays an important role in various sectors such as medical, law and history. The used of anatomy knowledge of human of the skull anatomy is in various sectors.

 

The sex differentiation is an important subject in medico-legal purposes. The cranial capacity of skulls are measured through various aspect such as length, breath, height, and the used of formula for measuring volume [1]. The conclusion can be made through the interrelationship between the sex dimorphism and their measurement. The sex differentiation of the skull is an important subjects in various medico-legal purposes. It helps the law and forensic practitioner to identify the sex of their specimen.

In this study, the Lee Pearson’s formula had been used as the method to calculate the cranial capacity. Many formulae had been proposed in order to predict the values of cranial capacity originated from principal cranial dimensions for various populations. However, the accuracy of the specific formulae on other human population is one of the problem facing by the authors. Obviously, there are no universal formulae that can be used as the relationship between the head dimension and cranial capacity that can show the influences of race, sex and age of an individual.

 

Based on the earlier study, the cranial capacity of female skull is 1/10 less than of the cranial capacity of man of the same race. The study of cranial capacity had been proved to be important in forensic, anthropology and law field.

 

MATERIALS AND METHODS:

38 dry human skulls originated from South India (20 males and 18 females) were obtained from the Department of Anatomy, Saveetha Dental College and Hospital, Chennai, Tamil Nadu, India, during the year of 2015. All the skulls used for this study are from the adult skulls which are approximately above 20 years. However, only intact without any damage known gender skulls will be examined and measured. Meanwhile, the skull with broken and damaged parts are excluded from the observation purposes.

 

In order to record the skull dimensions measurement, the external linear dimensions are used. The vernier caliper was used to measure the cranial length, cranial breadth and auricular head height of the skull .

 

The cranial length is taken in its maximum values of the straight distance between frontal bone which is the most prominent point on the nose root and the most noticeable occipital bone. The maximum length measurement is taken by using the anterior vernier caliper on the tip of frontal bone and its posterior vernier caliper on the tips of occipital bone along the medial part of skulls.

 

The cranial breadth is taken in its maximum values of the straight distance between parietal bones lateral points. The maximum breadth measurement is taken by using the vernier caliper on the both tips of the most noticeable lateral parietal bone.

 

The auricular head height is taken for its maximum values of the straight distance between the external acoustic meatus and vertex point of bregma on its highest. The maximum auricular head height is taken by using vernier caliper on both sides, right and left.

 

All the measurement are taken by same person to avoid any mistake and errors during the process. Furthermore, the measurement is taken three times and their mean are calculated.

 

For cranial capacity values, formulae is used for male and female (Lee and Pearson; William,2000).

 

For male cranial capacity, the formula is,

0.000337(C -11) (B- 11) (H-11) + 406.01

Where, C= Cranial Length, B= Cranial breadth, H= Auricular head Height

 

For female cranial capacity, the formula is,

0.000400(C -11) (B-11) (H-11) + 206.60

 

The result obtained is analyzed in order to find out the cranial cavity range, the cranial cavity mean, and its standard deviation (S.D). The pattern of the statistic evidence is interpreted to find out the differences between their cranial cavity and their sex dimorphism.

 

OBSERVATION AND RESULTS:

In this study, the cranial capacity for the male skulls are range from 963 CC to 1098 CC with their mean of 1030.05 CC. Meanwhile for the cranial capacity for female skulls are range from 757 CC to 890 CC with their mean of 850.24 C

 

 

Table 1: Range, Mean and Standard Deviation of Cranial Capacity for male and female skulls of South India

No	Parameter	Male (n= 20)	Female (n= 18)
1	Range	963.07 CC - 1098.98 CC	756.99 CC - 889.89 CC
2	Mean	1030.05 CC	850.24 CC
3	Standard Deviation	35.648 CC	40.944 CC
4	Mean +/-  Standard Deviation	994.402 CC- 1065.698 CC	809.296 CC -891.184 CC

                                                                    

 

 

Graph 1: Cranial Capacity (in CC) of Male and Female Skulls of South India

 

Sexual Dimorphism Index of Cranial Capacity:

 

=17.46%

 

 

DISCUSSION:

In this study, the cranial capacity of the adult skulls which are approximately above 20 years are taken as the study subject. The correlation between the cranial capacity of skulls and their sexual dimorphism are taken into consideration in result and conclusion of this study.

 

The present study on cranial of Adult South India Skulls for 38 skulls (20 male skulls and 18 female skulls), the mean capacity for male skulls is calculated to be 1030.050 +- 35.648 CC (range 963.071 CC - 1098.989 CC) and the mean capacity for female skulls is 850.24 +- 40.944 CC (range 756.992 CC - 889.898 CC).

 

In the previous study, there are some authors had estimated the cranial capacity by using several methods such as packing methods, linear dimensions and radiological methods [2]. The most accurate method in the study of cranial capacity is by using filling up the cranial cavity with seeds, lead shots or any small-like-seed things and pour them into a measuring cylinder for measurement purposes. Most of the studied had done shown the growth of the cranial capacity along the age from birth to childhood. The cranial capacity reaches the peak size by age of 16-20. Several study of cranial capacity on the different races had been done by several authors.

 

According to the Henry Gray (2000) in his study, skulls

can be classified based on their capacities which are microcephalic, mesocephalic and megacephalic [3]. Microcephalic is a cranial capacity that have less than 1350 CC. For example are the skulls originated from native Australian and Andaman Island. Mesocephalic is a cranial capacity that have values from 1350 CC to 1450 CC. For example are the skulls of Afrian Negroes and Chinese. Megacephalic is a cranial capacity that have values more than 1450 CC. For example are the skulls measured in Europe, Japan and Eskimos.

 

Based on the present study, it is observed that the overall mean cranial capacity of adult South India skulls are grouped as microcephalic which is less than 1350 CC for both sexes.

 

The first author that systematically measure skulls was Samueal G. Morton (1799-1851 A.D.), an American Physician. He had measured more than 1000 skulls from all around the world and made his conclusion that skulls of different races have different cranial capacity.

 

Table 2:  Comparison of studies done by other authors

Year	Authors	Place	Mean	Method used
1986	Ricklan	South Africa	Male:  1373.3±107.4 CC Female:  1251±101.1 CC	N/A
1995	Hwang	Korea	Male:  1470 ± 107 CC Female: 1317±117 CC	N/A
2007	Acer	Turkey	Male: 1141.64±118.9 CC Female: 1306±162.9 CC	Linear Dimensions Measurement
2010	Gohiya	Madhya Pradesh	Male:  1380.52±94.63 CC Female:  1188.75±91.16 CC	Filling and Packing Method
2015	Present study	South India	Male: 1030.050 ±35.648 CC Female: 850.24 ± 40.944 CC	Lee Pearson’s formula

[4][5][6][7][8]

 

Based on the Table 2, the male South African skulls are grouped in a mesocephalic as the skulls were observed to be 1373 ± 107.4 CC, meanwhile South African female skulls have microcephalic group. Korean population of cranial capacity for both sexes approximately have megacephalic group which are more than 1450 CC. The cranial capacity of population of Turkey are grouped as microcephalic as both sexes have less than 1350 CC of skulls.

 

Mostly, the Indian population (Madya Pradesh and present study, South India) shown that they are grouped in a microcephalic as they have approximately less than 1350 CC values.

 

The sexual dimorphism is a very important component in the morphological variation purposes of biological populations. In the present study of South India population, the sexual dimorphism index was shown to be higher than other places. The South India Sexual Dimorphism Index is 17.46%, which is higher than Sri

 

Lankas (8.46%), Caucasians (7.95%), Turkey (10.06%) and Koreans (10.3%) [9][10][11].

 

CONCLUSION:

In a medico-legal sectors, the determination of the sex can be done through the measurement of the cranial capacity of skulls. It is also important subjects to study the human evolution, race differences and for clinical practice for abnormalities study of cranial size. The bisexual variation of cranial capacity is observed in present study of South India skulls. Mean cranial capacity of male skulls was observed to be 1030.050 ± 35.648 CC (range 963.07 CC - 1098.98 CC), while in female skulls the mean cranial capacity was observed to be 850.24 ± 40.944 CC (range 756.99 CC - 889.90 CC). The mean cranial capacity of male skulls was studied to be higher than females, this agree with the similar study that had been done earlier by other authors.

 

REFERENCES:

1.     Lee, A. and Pearson, K. Data for the problem of evolution in man: VI. A first study of the correlation of the human skull. Philos. Trans. R. Soc. London., 196:225-64.

2.     Acer N, Usanmaz M, Tugay U and Ertekin T. Estimation of cranial capacity in 17-26 year old university students. Int. J. Morphol., 2007a; 25:65

3.     Gray Henry. Gray’s Anatomy: The anatomical basis of medicine and surgery. 37 Edition. New York, Churchill Livingstone,.

4.     Hwang Y, Lee KH, Choi BY, Lee KS, Lee HY, Sir WS, Kim HJ, Koh KS, Han SH, Chung MS and Kim H. Study on the Korean Adult Cranial Capacity. Journal of Korean Medical Science, 1995 August; 10(4):239-42. 

5.     Ilayperuma I. Cranial capacity in an adult Sri Lankan population: Sexual dimorphism and ethnic diversity. Int. J. Morphol., 2011; 29(2):479-84.

6.     Acer N, Sahin B, Bas D, Ertekin T, et al. Comparison of three methods for the estimation of total intracranial volume: stereologic, planimetric, and anthropometric approaches. Annals Plastic Surg 2007;56(1):48-53

7.     Manjunath KY. Estimation of cranial volume – An overview of methodologies. J. Anat. Soc. India, 2002a; 51:85-91.

8.     Muralidhar P Shepur, Magi M, Nanjundappa B, Pavan P Havaldar, Premalatha Gogi, Shaik Hussain Saheb. Morphometric Analysis Of Endocrani Al Capacity.  Int J Anat  Res 2014;2(1):242-48.

9.     Murli Lalwani, Jayanthi Yadav, Arneet Arora, B.P.Dubey. Sex Identification from Cranial Capacity of Adult Human Skulls. J Indian Acad Forensic Med., 2012; 34(2): 128-13.

10.   Sadakat Ali, AP Sinha, SL Jethani, RK Rohatgi, K Anamika. "Study of Cranial Capacity of Adult North Indian Human Skulls and its Sexual Dimorphism". International Journal of Scientifi c Study. 2014;1(5):29-31.

11.   Williams, P. L.; Bannister, L. H.; Berry, M. M. Collins, P.; Dyson, M. and Dussek, J. E. Gray’s Anatomy: The anatomical basis of medicine and surgery. 38 Ed. New York, Churchill Livingstone, 2000.

 

 

Accepted on 07.07.2016        © RJPT All right reserved

Research J. Pharm. and Tech 2016; 9(9):1389-1392.