The skull, along with the pelvic bone, serves an important source of clues as to the sex of human skeletal remains. The frontal bone is one of the most significant sexually dimorphic structures employed in anthropological research, especially when studied by methods of virtual anthropology. For this reason, many new methods have been developed, but their utility for other populations remains to be verified. In the present study, we tested one such approach-the landmark-free method of Bulut et al. (2016) for quantifying sexually dimorphic differences in the shape of the frontal bone, developed using a sample of the Turkish population. Our study builds upon this methodology and tests its utility for the Czech population. We evaluated the shape of the male and female frontal bone using 3D morphometrics, comparing virtual models of frontal bones and corresponding software-generated spheres. To do so, we calculated the relative size of the frontal bone area deviating from the fitted sphere by less than 1 mm and used these data to estimate the sex of individuals. Using our sample of the Czech population, the method estimated the sex correctly in 72.8% of individuals. This success rate is about 5% lower than that achieved with the Turkish sample. This method is therefore not very suitable for estimating the sex of Czech individuals, especially considering the significantly greater success rates of other approaches.

Department of Anthropology and Human Genetics Faculty of Science Charles University Prague Czech Republic

Department of Software and Computer Science Faculty of Mathematics and Physics Charles University Prague Czech Republic

Zobrazit více v PubMed

Small C, Schepartz L, Hemingway J, Brits D. Three-dimensional derived interlandmark distances for sex estimation in intact and fragmentary crania. Forensic Sci Int. 2018;287:127-35. https://doi.org/10.1016/j.forsciint.2018.02.012.

Nikita E. Quantitative sex estimation based on cranial traits using R functions. J Forensic Sci. 2019;64:175-80. https://doi.org/10.1111/1556-4029.13833.

Lopez-Capp TT, Rynn C, Wilkinson C, de Paiva LAS, Michel-Crosato E, Biazevic MGH. Discriminant analysis of mandibulat measurements for the estimation of sex in a modern Brazilian sample. Int J Legal Med. 2018;132:843-51. https://doi.org/10.1007/s00414-017-1681-8.

Tise ML, Kimmerle EH, Spradley MK. Craniometric variation of diverse populations in Florida: identification challenges within a border state. Ann Anthropol Pract. 2014;38:111-23. https://doi.org/10.1111/napa.12046.

Krüger GC, L’Abbé EN, Stull KE, Kenyhercz MW. Sexual dimorphism in cranial morphology among modern South Africans. Int J Legal Med. 2015;129:869-75. https://doi.org/10.1007/s00414-014-1111-0.

Musilová B, Dupej J, Brůžek J, Bejdová Š, Velemínská J. Sex and ancestry related differences between two Central European populations determined using exocranial meshes. Forensic Sci Int. 2019;297:364-9. https://doi.org/10.1016/j.forsciint.2019.02.034.

Bruzek J. A method for visual determination of sex, using the human hip bone. Am J Phys Anthropol. 2002;117:157-68. https://doi.org/10.1002/ajpa.10012.

Özer BK, Özer I, Sagir M, Gülec E. Sex determination using the tibia in an ancient anatolian population. Mediter Archeol Archaom. 2014;14:329-36.

Walker PL. Sexing skulls using discriminant function analysis of visually assessed traits. Am J Phys Anthropol. 2008;136:39-50. https://doi.org/10.1002/ajpa.20776.

Dempf R, Eckert AW. Contouring the forehead and rhinoplasty in the feminization of the face in male-to-female transsexuals. J Craniomaxillofacial Surg. 2010;38:416-22. https://doi.org/10.1016/j.jcms.2009.11.003.

Shearer BM, Sholts SB, Garvin HM, Wärmländer SKTS. Sexual dimorphism in human browridge volume measured from 3D models of dry crania: a new digital morphometrics approach. Forensic Sci Int. 2012;222:400.e1-e5. https://doi.org/10.1016/j.forsciint.2012.06.013.

Williams BA, Rogers TL. Evaluating the accuracy and precision of cranial morphological traits for sex determination. J Forensic Sci. 2006;51:729-35. https://doi.org/10.1111/j.1556-4029.2006.00177.x.

Garvin HM, Sholts SB, Mosca LA. Sexual dimorphism in human cranial trait scores: Effects of population, age, and body size. Am J Phys Anthropol. 2014;154:259-69. https://doi.org/10.1002/ajpa.22502.

Buikstra JE, Ubelaker DH. Standards for data collection from human skeletal remains: procceedings of a seminar at the field museum of natural history, organized by Jonathan Haas. Fayetteville: ARL Arkansas Archeological Survey; 1994.

Keen JA. A study of differences between male and female skulls. Am J Phys Anthropol. 1950;8:65-80. https://doi.org/10.1002/ajpa.1330080113.

Garvin HM, Ruff CB. Sexual dimorphism in skeletal browridge and chin morphologies determined using a new quantitative method. Am J Phys Anthropol. 2012;147:661-70. https://doi.org/10.1002/ajpa.22036.

Rosas A, Bastir M. Thin-plate spline analysis of allometry and sexual dimorphism in the human craniofacial complex. Am J Phys Anthropol. 2002;117:236-45. https://doi.org/10.1002/ajpa.10023.

Bulut O, Petaros A, Hizliol I, Wärmländer SKTS, Hekimoglu B. Sexual dimorphism in frontal bone roundness quantified by a novel 3D-based and landmar-free method. Forensic Sci Int. 2016;261:162.e1-5. https://doi.org/10.1016/j.forsciint.2016.01.028.

Čechová M, Dupej J, Brůžek J, Bejdová Š, Horák M, Velemínská J. Sex estimation using external morphology of the frontal bone and frontal sinuses in a contemporary Czech population. Int J Legal Med. 2019;133:1285-94. https://doi.org/10.1007/s00414-019-02063-8.

Dupej J, de Lázaro GR, Pereira-Pedro AS, Píšová H, Pelikán J, Bruner E. Comparing endocranial surfaces: Mesh superimposition and coherent point drift registration. In: Bruner E, Ogihara N, Tanabe H, editors. Digital endocasts, replacement of Neanderthals by modern humans series. Toyko, Japan: Springer; 2018. https://doi.org/10.1007/978-4-431-56582-6_10.

Kotěrová A, Velemínská J, Dupej J, Brzobohatá H, Pilný A, Brůžek J. Disregarding population specificity : its influence on the sex assessment methods from the tibia. Int J Legal Med. 2016;131:251-61. https://doi.org/10.1007/s00414-016-1413-5.

Scientific computing and imaging institute. Least squares fitting of data. http://www.sci.utah.edu/~balling/FEtools/doc_files/LeastSquaresFitting.pdf. Accessed 15 Aug 2020.

Cortes C, Vapnik V. Support-vector networks. Mach Learn. 1995;20:273-97. https://doi.org/10.1007/BF00994018.

Perlaza NA. Sex determination from the frontal bone: a geometric morphometric study. J Forensic Sci. 2014;59:1330-2. https://doi.org/10.1111/1556-4029.12467.

Hochstein LAE. The frontal bone as a proxy for sex estimation in humans: A geometric morphometric analysis (Master’s thesis). Baton Rouge, LA: Louisiana State University and Agricultural and Mechanical College; 2014.

Musilová B, Dupej J, Velemínská J, Chaumoitre K, Brůžek J. Exocranial surfaces for sex assessment of the human cranium. Forensic Sci Int. 2016;269:70-7. https://doi.org/10.1016/j.forsciint.2016.11.006.

Bejdová Š, Krajíček V, Velemínská J, Horák M, Velemínský P. Changes in the sexual dimorphism of the human mandible during the last 1200 years in Central Europe. HOMO. 2013;64:437-53. https://doi.org/10.1016/j.jchb.2013.05.003.

Bejdová Š, Dupej J, Krajíček V, Velemínská J, Velemínský P. Stability of upper face sexual dimorphism in central European population (Czech Republic) during the modern age. Int J Legal Med. 2017;132:321-30. https://doi.org/10.1007/s00414-017-1625-3.

Brzobohatá H, Prokop J, Horák M, Jančárek A, Velemínský J. Accuracy and benefits of 3D bone surface modelling: a comparison of two methods of surface data acquisition reconstructed by laser scanning and computered tomography outputs. Coll Anthropol. 2012;36:801-6.

The influence of biological relatedness on sexual dimorphism and sex classification based on external morphology of the frontal bone