A geometric morphometric assessment of the hard tissue external auditory meatus and soft tissue ear of South Africans
Research on how to reliably reconstruct the shape of the ear for facial approximations is limited, especially in countries such as South Africa where standard ear casts are still used in manual methods. To improve objectivity, computer aided methods are being developed for facial approximations – wh...
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| Format: | Article |
| Language: | English |
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Elsevier
2023-12-01
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| Series: | Forensic Science International: Reports |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2665910723000269 |
| _version_ | 1797390400982351872 |
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| author | Meg-Kyla Erasmus Ericka Noelle L’Abbé Alison Fany Ridel |
| author_facet | Meg-Kyla Erasmus Ericka Noelle L’Abbé Alison Fany Ridel |
| author_sort | Meg-Kyla Erasmus |
| collection | DOAJ |
| description | Research on how to reliably reconstruct the shape of the ear for facial approximations is limited, especially in countries such as South Africa where standard ear casts are still used in manual methods. To improve objectivity, computer aided methods are being developed for facial approximations – which require extensive population specific datasets for facial feature morphology. This study aims to assess variations in the shape of the ear and the underlying external auditory meatus (EAM) through the analysis of cone-beam computed tomography (CBCT) scans of 40 black South Africans (males n = 17; females n = 23) and 76 white South Africans (males n = 29; females n = 47) between the ages of 18 and 90 years. Shape data was collected by placing 19 capulometric landmarks on the 3D reconstructions of the ear and 46 sliding craniometric landmarks along the EAM. Geometric morphometric analysis revealed highly significant variation in ear shape between groups for population affinity (p-value = 0.001), while sex and age were only significant between the white South Africans (p-value < 0.05). Only population affinity significantly influenced shape in the EAM (p-value = 0.001), and both the ear and EAM showed significant levels of symmetry (p-value = 0.007). While an ear will never be exactly recreated, basing facial estimates on the decedent’s biological profile can lead towards the highest possible accuracies. For the ear shape specifically, sex and age will not be a priority when creating predictive models, but population affinity will greatly influence the output. |
| first_indexed | 2024-03-08T23:11:10Z |
| format | Article |
| id | doaj.art-231ada514af34ce298634ea86adfc7ee |
| institution | Directory Open Access Journal |
| issn | 2665-9107 |
| language | English |
| last_indexed | 2024-03-08T23:11:10Z |
| publishDate | 2023-12-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Forensic Science International: Reports |
| spelling | doaj.art-231ada514af34ce298634ea86adfc7ee2023-12-15T07:25:50ZengElsevierForensic Science International: Reports2665-91072023-12-018100331A geometric morphometric assessment of the hard tissue external auditory meatus and soft tissue ear of South AfricansMeg-Kyla Erasmus0Ericka Noelle L’Abbé1Alison Fany Ridel2Correspondence to: 9 Bophelo Road, Prinshof, Pretoria 0184, South Africa.; Forensic Anthropology Research Centre, Department of Anatomy, Faculty of Health Sciences, University of Pretoria, 9 Bophelo Road, Prinshof, Pretoria 0184, South AfricaForensic Anthropology Research Centre, Department of Anatomy, Faculty of Health Sciences, University of Pretoria, 9 Bophelo Road, Prinshof, Pretoria 0184, South AfricaForensic Anthropology Research Centre, Department of Anatomy, Faculty of Health Sciences, University of Pretoria, 9 Bophelo Road, Prinshof, Pretoria 0184, South AfricaResearch on how to reliably reconstruct the shape of the ear for facial approximations is limited, especially in countries such as South Africa where standard ear casts are still used in manual methods. To improve objectivity, computer aided methods are being developed for facial approximations – which require extensive population specific datasets for facial feature morphology. This study aims to assess variations in the shape of the ear and the underlying external auditory meatus (EAM) through the analysis of cone-beam computed tomography (CBCT) scans of 40 black South Africans (males n = 17; females n = 23) and 76 white South Africans (males n = 29; females n = 47) between the ages of 18 and 90 years. Shape data was collected by placing 19 capulometric landmarks on the 3D reconstructions of the ear and 46 sliding craniometric landmarks along the EAM. Geometric morphometric analysis revealed highly significant variation in ear shape between groups for population affinity (p-value = 0.001), while sex and age were only significant between the white South Africans (p-value < 0.05). Only population affinity significantly influenced shape in the EAM (p-value = 0.001), and both the ear and EAM showed significant levels of symmetry (p-value = 0.007). While an ear will never be exactly recreated, basing facial estimates on the decedent’s biological profile can lead towards the highest possible accuracies. For the ear shape specifically, sex and age will not be a priority when creating predictive models, but population affinity will greatly influence the output.http://www.sciencedirect.com/science/article/pii/S2665910723000269Forensic anthropologyFacial approximationExternal ear shape variationCone-beam computed tomographyGeometric morphometric methodsAnatomical and sliding landmarks |
| spellingShingle | Meg-Kyla Erasmus Ericka Noelle L’Abbé Alison Fany Ridel A geometric morphometric assessment of the hard tissue external auditory meatus and soft tissue ear of South Africans Forensic Science International: Reports Forensic anthropology Facial approximation External ear shape variation Cone-beam computed tomography Geometric morphometric methods Anatomical and sliding landmarks |
| title | A geometric morphometric assessment of the hard tissue external auditory meatus and soft tissue ear of South Africans |
| title_full | A geometric morphometric assessment of the hard tissue external auditory meatus and soft tissue ear of South Africans |
| title_fullStr | A geometric morphometric assessment of the hard tissue external auditory meatus and soft tissue ear of South Africans |
| title_full_unstemmed | A geometric morphometric assessment of the hard tissue external auditory meatus and soft tissue ear of South Africans |
| title_short | A geometric morphometric assessment of the hard tissue external auditory meatus and soft tissue ear of South Africans |
| title_sort | geometric morphometric assessment of the hard tissue external auditory meatus and soft tissue ear of south africans |
| topic | Forensic anthropology Facial approximation External ear shape variation Cone-beam computed tomography Geometric morphometric methods Anatomical and sliding landmarks |
| url | http://www.sciencedirect.com/science/article/pii/S2665910723000269 |
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