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Advanced procedures for skull sex estimation using sexually dimorphic morphometric features

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Abstract

This paper introduces an automated method for estimating sex from cranial sex diagnostic traits by extracting and evaluating specialized morphometric features from the glabella, the supraorbital ridge, the occipital protuberance, and the mastoid process. The proposed method was developed and evaluated using two European population samples, a Czech sample comprising 170 crania reconstructed from anonymized CT scans and a Greek sample of 156 crania from the Athens Collection. It is based on a fully automatic algorithm applied on 3D models for extracting sex diagnostic morphometric features which are further processed by computer vision and machine learning algorithms. Classification accuracy was evaluated in a population specific and a population generic 2-way cross-validation scheme. Population-specific accuracy for individual morphometric features ranged from 78.5 to 96.7%, whereas population generic correct classification ranged from 71.7 to 90.8%. Combining all sex diagnostic traits in multi-feature sex estimation yielded correct classification performance in excess of 91% for the entire sample, whereas the sex of about three fourths of the sample could be determined with 100% accuracy according to posterior probability estimates. The proposed method provides an efficient and reliable way to estimate sex from cranial remains, and it offers significant advantages over existing methods. The proposed method can be readily implemented with the skullanalyzer computer program and the estimate_sex.m GNU Octave function, which are freely available under a suitable license.

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Availability of data and material

All data used in the present study are publicly available at Zenodo repository. See manuscript for more details.

References

  1. Bruzek J (2002) A method for visual determination of sex, using the human hip bone. Am J Phys Anthropol 117:157–168. https://doi.org/10.1002/ajpa.10012

    Article  PubMed  Google Scholar 

  2. Nikita E, Michopoulou E (2018) A quantitative approach for sex estimation based on cranial morphology. Am J Phys Anthropol 165:507–517. https://doi.org/10.1002/ajpa.23376

    Article  PubMed  Google Scholar 

  3. Bertsatos A, Papageorgopoulou C, Valakos E, Chovalopoulou M-E (2018) Investigating the sex-related geometric variation of the human cranium. Int J Legal Med 132:1505–1514. https://doi.org/10.1007/s00414-018-1790-z

    Article  PubMed  Google Scholar 

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

    Article  PubMed  Google Scholar 

  5. Oikonomopoulou E-K, Valakos E, Nikita E (2017) Population-specificity of sexual dimorphism in cranial and pelvic traits: evaluation of existing and proposal of new functions for sex assessment in a Greek assemblage. Int J Legal Med 131:1731–1738. https://doi.org/10.1007/s00414-017-1655-x

    Article  PubMed  Google Scholar 

  6. Bruzek J, Murail P (2006) Methodology and reliability of sex determination from the skeleton. In: Schmitt A, Cunha E, Pinheiro J (eds) Forensic anthropology and medicine. Humana Press, Totowa, NJ, pp 225–242

    Chapter  Google Scholar 

  7. Spradley MK, Jantz RL (2011) Sex estimation in forensic anthropology: skull versus postcranial elements. J Forensic Sci 56:289–296. https://doi.org/10.1111/j.1556-4029.2010.01635.x

    Article  PubMed  Google Scholar 

  8. Williams BA, Rogers TL (2006) Evaluating the accuracy and precision of cranial morphological traits for sex determination. J Forensic Sci 51:729–735. https://doi.org/10.1111/j.1556-4029.2006.00177.x

    Article  PubMed  Google Scholar 

  9. Krüger GC, L’Abbé EN, Stull KE, Kenyhercz MW (2015) Sexual dimorphism in cranial morphology among modern South Africans. Int J Legal Med 129:869–875. https://doi.org/10.1007/s00414-014-1111-0

    Article  PubMed  Google Scholar 

  10. Langley NR, Dudzik B, Cloutier A (2018) A decision tree for nonmetric sex assessment from the skull. J Forensic Sci 63:31–37. https://doi.org/10.1111/1556-4029.13534

    Article  PubMed  Google Scholar 

  11. Godde K, Thompson MM, Hens SM (2018) Sex estimation from cranial morphological traits: use of the methods across American Indians, modern North Americans, and ancient Egyptians. HOMO 69:237–247. https://doi.org/10.1016/j.jchb.2018.09.003

    Article  CAS  PubMed  Google Scholar 

  12. Kranioti EF, İşcan MY, Michalodimitrakis M (2008) Craniometric analysis of the modern Cretan population. Forensic Sci Int 180:110.e1–110.e5. https://doi.org/10.1016/j.forsciint.2008.06.018

    Article  Google Scholar 

  13. Franklin D, Cardini A, Flavel A, Kuliukas A (2013) Estimation of sex from cranial measurements in a Western Australian population. Forensic Sci Int 229:158.e1–158.e8. https://doi.org/10.1016/j.forsciint.2013.03.005

    Article  Google Scholar 

  14. Casado AM (2017) Quantifying sexual dimorphism in the human cranium: a preliminary analysis of a novel method. J Forensic Sci 62:1259–1265. https://doi.org/10.1111/1556-4029.13441

    Article  PubMed  Google Scholar 

  15. Bigoni L, Velemínská J, Brůžek J (2010) Three-dimensional geometric morphometric analysis of cranio-facial sexual dimorphism in a Central European sample of known sex. HOMO 61:16–32. https://doi.org/10.1016/j.jchb.2009.09.004

    Article  CAS  PubMed  Google Scholar 

  16. Chovalopoulou M-E, Valakos ED, Manolis SK (2013) Sex determination by three-dimensional geometric morphometrics of the palate and cranial base. Anthropol Anz 70:407–425. https://doi.org/10.1127/0003-5548/2013/0363

    Article  PubMed  Google Scholar 

  17. Chovalopoulou M-E, Valakos ED, Manolis SK (2016) Sex determination by three-dimensional geometric morphometrics of the vault and midsagittal curve of the neurocranium in a modern Greek population sample. HOMO 67:173–187. https://doi.org/10.1016/j.jchb.2015.09.007

    Article  PubMed  Google Scholar 

  18. Chovalopoulou M-E, Valakos ED, Manolis SK (2016) Sex determination by three-dimensional geometric morphometrics of craniofacial form. Anthropol Anz 73:195–206. https://doi.org/10.1127/anthranz/2016/0470

    Article  PubMed  Google Scholar 

  19. Gao H, Geng G, Yang W (2018) Sex determination of 3D skull based on a novel unsupervised learning method. Comput Math Methods Med 2018:1–10. https://doi.org/10.1155/2018/4567267

    Article  Google Scholar 

  20. Čechová M, Dupej J, Brůžek J, Bejdová Š, Horák M, Velemínská J (2019) Sex estimation using external morphology of the frontal bone and frontal sinuses in a contemporary Czech population. Int J Legal Med 133:1285–1294. https://doi.org/10.1007/s00414-019-02063-8

    Article  PubMed  Google Scholar 

  21. Garvin HM, Ruff CB (2012) Sexual dimorphism in skeletal browridge and chin morphologies determined using a new quantitative method. Am J Phys Anthropol 147:661–670. https://doi.org/10.1002/ajpa.22036

    Article  PubMed  Google Scholar 

  22. Schlager S, Rüdell A (2017) Sexual dimorphism and population affinity in the human zygomatic structure-comparing surface to outline data: analyzing zygomatic shape. Anat Rec 300:226–237. https://doi.org/10.1002/ar.23450

    Article  Google Scholar 

  23. Bejdová Š, Dupej J, Krajíček V, Velemínská J, Velemínský P (2018) Stability of upper face sexual dimorphism in central European populations (Czech Republic) during the modern age. Int J Legal Med 132:321–330. https://doi.org/10.1007/s00414-017-1625-3

    Article  PubMed  Google Scholar 

  24. Luo L, Wang M, Tian Y, Duan F, Wu Z, Zhou M, Rozenholc Y (2013) Automatic sex determination of skulls based on a statistical shape model. Comput Math Methods Med 2013:1–6. https://doi.org/10.1155/2013/251628

    Article  Google Scholar 

  25. Arigbabu OA, Liao IY, Abdullah N, Mohamad Noor MH (2017) Computer vision methods for cranial sex estimation. IPSJ Trans Comput Vis Appl 9:19. https://doi.org/10.1186/s41074-017-0031-6

    Article  Google Scholar 

  26. Walrath DE, Turner P, Bruzek J (2004) Reliability test of the visual assessment of cranial traits for sex determination. Am J Phys Anthropol 125:132–137. https://doi.org/10.1002/ajpa.10373

    Article  PubMed  Google Scholar 

  27. Lewis CJ, Garvin HM (2016) Reliability of the Walker cranial nonmetric method and implications for sex estimation. J Forensic Sci 61:743–751. https://doi.org/10.1111/1556-4029.13013

    Article  PubMed  Google Scholar 

  28. Fruciano C (2016) Measurement error in geometric morphometrics. Dev Genes Evol 226:139–158. https://doi.org/10.1007/s00427-016-0537-4

    Article  PubMed  Google Scholar 

  29. Shearer BM, Cooke SB, Halenar LB, Reber SL, Plummer JE, Delson E, Tallman M (2017) Evaluating causes of error in landmark-based data collection using scanners. PLoS One 12:e0187452. https://doi.org/10.1371/journal.pone.0187452

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  30. Bertsatos A, Athanasopoulou K, Chovalopoulou M-E (2019) Estimating sex using discriminant analysis of mandibular measurements from a modern Greek sample. Egypt J Forensic Sci 9:25. https://doi.org/10.1186/s41935-019-0133-7

    Article  Google Scholar 

  31. Noble J, Flavel A, Aviv R, Franklin D (2019) Forensic anthropological standards for cranial sex estimation in Canada: preliminary results. Aust J Forensic Sci 51:S1–S4. https://doi.org/10.1080/00450618.2019.1569720

    Article  Google Scholar 

  32. Kanchan T, Gupta A, Krishan K (2013) Estimation of sex from mastoid triangle – a craniometric analysis. J Forensic Legal Med 20:855–860. https://doi.org/10.1016/j.jflm.2013.06.016

    Article  Google Scholar 

  33. Petaros A, Sholts SB, Slaus M, Bosnar A, Wärmländer SKTS (2015) Evaluating sexual dimorphism in the human mastoid process: a viewpoint on the methodology. Clin Anat 28:593–601. https://doi.org/10.1002/ca.22545

    Article  PubMed  Google Scholar 

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

    Article  Google Scholar 

  35. Nikita E (2019) Quantitative sex estimation based on cranial traits using R functions. J Forensic Sci 64:175–180. https://doi.org/10.1111/1556-4029.13833

    Article  PubMed  Google Scholar 

  36. Yang W, Liu X, Wang K, Hu J, Geng G, Feng J (2019) Sex determination of three-dimensional skull based on improved backpropagation neural network. Comput Math Methods Med 2019:1–8. https://doi.org/10.1155/2019/9163547

    Article  Google Scholar 

  37. Yang W, Zhou M, Zhang P, Geng G, Liu X, Zhang H (2020) Skull sex estimation based on wavelet transform and Fourier transform. Biomed Res Int 2020:1–10. https://doi.org/10.1155/2020/8608209

    Article  Google Scholar 

  38. Eliopoulos C, Lagia A, Manolis S (2007) A modern, documented human skeletal collection from Greece. HOMO 58:221–228. https://doi.org/10.1016/j.jchb.2006.10.003

    Article  CAS  PubMed  Google Scholar 

  39. Bertsatos A, Gkaniatsou E, Papageorgopoulou C, Chovalopoulou M-E (2019) “What and how should we share?” An inter-method inter-observer comparison of measurement error with landmark-based craniometric datasets. Anthropol Anz 92489. https://doi.org/10.1127/anthranz/2019/1047

  40. Cignoni P, Callieri M, Corsini M, et al (2008) MeshLab: an open-source mesh processing tool. Eurographics Ital chapter Conf 8 pages. https://doi.org/10.2312/LOCALCHAPTEREVENTS/ITALCHAP/ITALIANCHAPCONF2008/129-136

  41. Mineo C, Pierce SG, Nicholson PI, Cooper I (2016) Robotic path planning for non-destructive testing – a custom MATLAB toolbox approach. Robot Comput Integr Manuf 37:1–12. https://doi.org/10.1016/j.rcim.2015.05.003

    Article  Google Scholar 

  42. Mineo C, Pierce SG, Nicholson PI, Cooper I (2017) Introducing a novel mesh following technique for approximation-free robotic tool path trajectories. J Comput Des Eng 4:192–202. https://doi.org/10.1016/j.jcde.2017.01.002

    Article  Google Scholar 

  43. Mineo C, Pierce SG, Summan R (2019) Novel algorithms for 3D surface point cloud boundary detection and edge reconstruction. J Comput Des Eng 6:81–91. https://doi.org/10.1016/j.jcde.2018.02.001

    Article  Google Scholar 

  44. Bertsatos A (2019) Skullanalyzer: a concrete way of extracting cranial morphometric features. Zenodo. https://doi.org/10.5281/zenodo.3594565

  45. Bertsatos A (2019) User Manual & Algorithm Description Document “skullanalyzer” v1.0. Zenodo. https://doi.org/10.5281/zenodo.3519248

  46. Eaton JW, Bateman D, Hauberg S, Wehbring R (2019) GNU Octave version 5.1.0 manual: a high-level interactive language for numerical computations

  47. Bertsatos A, Chovalopoulou M-E, Brůžek J, Bejdová S (2020) Cranial morphometric features from Greek and Czech population samples. Zenodo. https://doi.org/10.5281/zenodo.3632180

  48. Bertsatos A, Chovalopoulou M-E (2018) Secular change in adult stature of modern Greeks. Am J Hum Biol 30:e23077. https://doi.org/10.1002/ajhb.23077

    Article  Google Scholar 

  49. Han H, Jiang X (2014) Overcome support vector machine diagnosis overfitting. Cancer Inform 13s1:CIN.S13875. https://doi.org/10.4137/CIN.S13875

  50. Nieves JW, Formica C, Ruffing J, Zion M, Garrett P, Lindsay R, Cosman F (2004) Males have larger skeletal size and bone mass than females, despite comparable body size. J Bone Miner Res 20:529–535. https://doi.org/10.1359/JBMR.041005

    Article  PubMed  Google Scholar 

  51. Brůžek J, Santos F, Dutailly B, Murail P, Cunha E (2017) Validation and reliability of the sex estimation of the human os coxae using freely available DSP2 software for bioarchaeology and forensic anthropology. Am J Phys Anthropol 164:440–449. https://doi.org/10.1002/ajpa.23282

    Article  PubMed  Google Scholar 

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Acknowledgments

The authors are grateful to Dr. Carmelo Mineo from the Strathclyde University for providing a customized algorithm to extract the ectocranial surface of the DICOM-derived 3D models, which enabled the inclusion of the Czech population sample in this study, and to Mr. Christos Garoufis from the National Technical University of Athens for his help with the Python scripting language. The authors wish to thank Dr. Martin Horák for managing the CT imaging in Na Homolce Hospital and are also thankful to Dr. Jana Velemínská from the Charles University and Prof. Efstratios Valakos from the National and Kapodistrian University of Athens for permission to study the Czech and Greek population samples respectively.

Funding

This work was partially supported by an Erasmus+ internship program (7026/2018) issued by the State Scholarships Foundation (Greece) granted to Andreas Bertsatos.

Author information

Authors and Affiliations

  1. Department of Animal and Human Physiology, Faculty of Biology, School of Sciences, University of Athens, Panepistimiopolis, GR 157 01, Athens, Greece

    Andreas Bertsatos

  2. Science and Technology in Archaeology and Culture Research Center, The Cyprus Institute, 2121 Aglantzia, Nicosia, Cyprus

    Maria-Eleni Chovalopoulou

  3. Department of Anthropology and Human Genetics, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic

    Jaroslav Brůžek & Šárka Bejdová

Authors
  1. Andreas Bertsatos
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  2. Maria-Eleni Chovalopoulou
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  3. Jaroslav Brůžek
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  4. Šárka Bejdová
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Correspondence to Andreas Bertsatos.

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The authors declare that they have no conflict of interest.

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The patients’ DICOM data have been used upon the approval of the ethics committee of the respective hospital hospital. See manuscript for more details.

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All code of custom built software is licensed under the GNU GPL v3 open source license and is available at GitHub. See manuscript for more details.

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Bertsatos, A., Chovalopoulou, ME., Brůžek, J. et al. Advanced procedures for skull sex estimation using sexually dimorphic morphometric features. Int J Legal Med 134, 1927–1937 (2020). https://doi.org/10.1007/s00414-020-02334-9

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