Research Article

Sex determination using mastoid, , and porion triangle in South Indian population C. Prathiba Reichal, Ganesh Lakshmanan*, M. S. Thenmozhi

ABSTRACT

Aim: This study aims to determine the sex of South Indian population using mastoid, asterion, and porion triangle. Materials and Methods: The study involved 50 human adult (25 males and 25 females). The following parameters are measured using Vernier caliper: (1) Length between zygoma root and asterion, (2) length between asterion and porion, and (3) length between asterion and mastoid – The distance between the two projecting points on the . Results: Males have significantly higher values than females using the three parameters. Statistical Analysis: Data were expressed as mean and standard deviation.

KEY WORDS: Sex determination, Dry skull, Asterion, Porion

INTRODUCTION Sex determination from skeleton is a significant step in the analysis of forensic anthropology. The relation Sex refers to set of biological attributes in humans between morphological characteristics and the and animals. It is primarily associated with physical gender of the skull is of great importance in forensic and physiological features including chromosome, anthropology research.[4] gene expression, hormone levels and function, and reproduction/sexual anatomy.[1] Sex is usually The human skull is a bony structure that forms the categorized as female or male, but there is variation head in the human skeleton. These morphological in the biological attributes that comprise sex and how differences support the facial structures and form those attributes are expressed. cavity for the brain. Like the skulls of other vertebrates, it protects the brain from injury.[5] The Sexual dimorphism is where the two sexes of the and the facial skeleton are the two different parts of same species exhibit various types of characteristic skull which have embryological origin. The upper area differences beyond the differences in their sexual of the cranial forms the {skull cap}. organs. The condition occurs in many animals and some The facial skeleton is formed by the bones supporting plants.[2] Differences may include secondary sexual the face.[6] characteristics, size, weight, color, and markings and may also include behavioral and cognitive differences. The differences in human skull of both sexes are that These differences may be subtle or exaggerated and male skulls have more prominent supraorbital ridges, may be subjected to sexual selection. The opposite a more prominent glabella and more prominent of dimorphism is monomorphism. There are mainly temporal lines. Female skulls generally have rounder four available methods of sex determination that is orbits and narrower jaws.[7] Male skulls on average morphological, metrical, geometrical morphometrics, have larger, broader palates, squarer orbits, larger and molecular.[3] mastoid processes, larger sinuses, and larger occipital condyles than those of females.[8] Access this article online The sex of each individual can be determined by Website: jprsolutions.info ISSN: 0975-7619 the determination of the area of triangle formed

Department of Anatomy, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India

*Corresponding author: Dr. Ganesh Lakshmanan, Department of Anatomy, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai - 600 077, Tamil Nadu, India. Phone: +91-9894999243. E-mail: [email protected]

Received on: 10-10-2018; Revised on: 21-12-2018; Accepted on: 24-01-2019

Drug Invention Today | Vol 11 • Issue 6 • 2019 1349 C. Prathiba Reichal, et al. by the mastoid, asterion, and porion which is RESULTS present in the human skull. This was described by De Paiva.[9] The aim of our study was to According to the values that were measured by determine the sex of the individual skull using calculating the area of MAP triangle in both male and these mastoidale, asterion, and porion points. female skull showed that male has a greater area of The mastoidale point indicates the most inferior MAP triangle when compared with that of female. By point of mastoid process. The asterion indicates this methodology, it is evaluated that sexual dimorphism the meeting point with lambdoid and the porion exists in human skull which can be of great significance in the field of forensic and anthropology. indicates the root of the zygoma.[10]

MATERIALS AND METHODS A total of 50 dry adult skulls from the Department of Anatomy at Saveetha Dental College, Poonamallee, Chennai, were used for the study. The skulls were thoroughly checked for any deformities. The points were measured by digital Vernier caliper. The mean, SD, maximal and minimal, geometric mean, area of MAP triangle, and sexual dimorphism ratio are calculated, computed, and compared between male and female skulls.

DISCUSSION One of the well-established subjects in anthropology is sexual dimorphism. With the help of human skulls, precise determination of sex can be done which will REFERENCES serve as a great importance to osteologist people, and forensic and anthropologist people. A practical 1. Schafer AJ, Fellow PN. Sex determination in humans. BioEssays 1996;18:955-63. alternative method is used in this current study for the 2. Wood CG, Lynch JM. Sexual dimorphism in the craniofacial technique of sexing skull.[11] Factors such as genetic, skeleton of modern humans. In: Marcus LF, Corti M, Loy A, environment, physical, and nutritional also serve as Naylor GJ, Slice DE, editors. Advances in Morphometrics. great morphological differences between male and Boston, MA, US: Springer; 1996. p. 407-14. 3. Wanek V. A Qualitative Analysis for Sex Determination in [12] female. Since males have more muscle mass and Humans Utilizing Posterior and Medial Aspects of the Distal more of weight, their architectural development also Humerus. Dissertations and Theses. makes some differences. When the mean of male right 4. Franchi A, Valette S, Agier R, Prost R, Kéchichan R, Fanton L. The prospects for application of computational anatomy in MAP triangle is measured, it summed up to 917.9. forensic anthropology for sex determination. Forensic Sci Int Similarly, female mean area of MAP triangle also 2019;297:156-60. was calculated which has a value of 816.6. Likewise, 5. Jones KL, Smith DW. Smith’s Recognizable Patterns of Human Malformation. Philadelphia, PA: Elsevier Saunders; 2006. male and female left mean area of MAP triangle was 6. Hauser G, De Stefano GF. Epigenetic Variants of the Human also calculated which showed the values of 909.3 and Skull; 1989. Available from: https://www.schweizerbart. 802.0. In like manner, the standard deviation of these de/publications/detail/isbn/9783510651412/Hauser__De_ four types of skulls was calculated which showed a Stefano_Epigenetic_Variants. [Last accessed on 2019 Feb 01]. 7. Austad SN. Using sex differences in aging in laboratory value of male right is 113.8, female right is 94.3, male animals to understand human sex differences. Innov Aging left is 110.0, and female left is 89.8. While comparing 2017;1 Suppl 1:1079. these values between male and female, it is evaluated 8. Mugilan MR, Babu Y, Ganesh K. Morphometric analysis of location and position of foramens present in the middle base of that morphological differences are found in sexual the skull. Int J Curr Adv Res 2017;6:2902-3. dimorphism. For the determination of sex of an 9. Paiva LA, Segre M. Sexing the human skull through the unknown skull, this MAP can be used as an additive mastoid process. Rev Hosp Clín 2003;58:15-20. value.[13] Triangular area of mastoid process is found 10. Mann F, editor. Section 11-Mastoid process area: Roughly gall bladder 12; G12; GB12. In: Reinventing Acupuncture. 2nd ed. to be significantly high in males when it is compared Edinburgh: Butterworth-Heinemann; 2000. p. 179-80. to female. 11. St Hoyme LE, Iscan MY. Determination of sex and race: Accuracy and assumptions. Reconstr Life Skeleton 1989;7:53-93. 12. Gupta G. Sex determination in North Indian population using Group Numbers Mean area SD map triangle. J Anat Soc India 2017;66:S79. Male right 25 917.9 113.8 13. Kumar SP, Karpagam K. Sex determination using dry human Male left 25 909.3 110.0 scapula. Int J Curr Adv Res 2017;6:3284-6. Female right 25 816.6 94.3 Female left 25 802.0 89.8 Source of support: Nil; Conflict of interest: None Declared

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