The human mandible (lower jaw bone) can be analyzed to determine gender and is commonly used in forensic science for this purpose. The pelvic bone is the only human bone more accurate in gender determination than the mandible. Mandibles have several distinctive characteristics that provide reliable information to determine gender. Teeth, bone shape and distance measurements can all distinguish between a male and female mandible. Observations for gender indication in children are less accurate.
The angle at the back of the lower jaw bone (mandibular or gonial angle), where the bone angles up toward the ear on either side, has marked differences between the males and females. The most significant difference is the flare or protrusion that the area around this angle exhibits. It is found in females that the area is smooth without protrusion; in males, the area protrudes and, in extreme cases, is flared.
Determination of gender by analysis of the teeth is marked as the most accurate method. Males, in general, have more pronounced and larger features than females. Canine teeth in females are both smaller in diameter than the male canines and they are set closer together. Male canines also have a larger distance between them than those of females.
Male mandibles are discernible by the squarish or bilobate shape of the chin. Female chin structures are more often pointed; however, they can display a squarish form. The analysis of the chin alone is less reliable in determining gender and should be used in congruence with other indicators.
The mandibles of children, especially those who have not experienced puberty, are significantly less reliable for indicating gender. The hormones released during puberty produce changes in the bone structures of humans, and some of the sexually defining characteristics don't occur until triggered by the hormones. The most reliable indicator of gender determination from mandible analysis is the size of the tooth crowns. Tooth crowns are determined by genetics and don't change in size of shape after initial development.
- Int. J. Morphol., 26(4):845-848, Blind Test of Mandibular Morphology with Sex Indicator in Subadult Mandibles, Iván Claudio Suazo Galdames, Daniela Alejandra Zavando Matamala, Ricardo Luiz Smith, 2008.
- The Internet Journal of Dental Science, 4(2), S. K. Dhattarwal, Manish Madan, S.C. Anand Prof. (Brig.), Balwant Rai, 2007
- Dictionary by Falrex
- J Forensic Sci., 51(6):1376-82., Sex determination using nonmetric characteristics of the mandible in Koreans, Hu KS, Koh KS, Han SH, Shin KJ, Kim HJ., Nov. 2006
- Photo Credit Digital Vision/Digital Vision/Getty Images
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