Aspects of Facial Features in a South African Sample As Applicable for Facial Approximations
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Aspects of facial features in a South African sample as applicable for facial approximations by Heléne Francia Dorfling Dissertation submitted in fulfilment of the requirements for the degree of MASTER OF SCIENCES in the FACULTY OF HEALTH SCIENCES Department of Anatomy University of Pretoria 2017 DECLARATION I declare that the dissertation that I am hereby submitting to the University of Pretoria for the MSc degree in Anatomy is my own work and that I have never before submitted it to any other tertiary institution for any degree. _____________________ Heléne Francia Dorfling ______day of ______________2017 ii CONTENTS Summary ………………………………………………………………………………………………………………………….v Acknowledgements ................................................................................................................. vii List of tables............................................................................................................................ viii List of figures ............................................................................................................................ ix 1. Introduction .............................................................................................................. 1 1.1. Aim ............................................................................................................................ 4 2. Literature review ...................................................................................................... 5 2.1. Applied osteology of the skull .................................................................................... 5 2.1.1. Anterior view...................................................................................................... 6 2.1.2. Lateral view ........................................................................................................ 9 2.1.3. The Bony Orbits.................................................................................................. 9 2.2. Anatomy of the facial features ................................................................................. 12 2.2.1. The Eyes ........................................................................................................... 14 2.2.2. The Nose .......................................................................................................... 16 2.2.3. The Lips ............................................................................................................ 19 2.2.4. The External Ears.............................................................................................. 22 2.3. Known guidelines for reconstructing facial features in a forensic setting ............. 24 2.3.1. The Eyes ........................................................................................................... 24 2.3.2. The Nose .......................................................................................................... 27 2.3.3. The Mouth........................................................................................................ 29 2.3.4. The Ears ............................................................................................................ 30 2.4. Possible shortcomings of established guidelines .................................................... 32 3. Materials and methods........................................................................................... 34 3.1. Sample ....................................................................................................................... 34 3.2. Ethical considerations ............................................................................................... 35 3.3. Methodology ............................................................................................................. 35 3.3.1. Orbital and ocular measurements ................................................................... 39 3.3.2. Nasal measurements ....................................................................................... 48 iii 3.3.3. Oral measurements ......................................................................................... 55 3.3.4. Auricular measurements.................................................................................. 59 3.4. Statistical analyses: Intra - and inter-observer repeatability testing ..................... 61 4. Results ..................................................................................................................... 63 4.1. Intra-observer repeatability testing and standard deviations on individual measurements........................................................................................................... 63 4.2. Inter-observer repeatability testing ......................................................................... 64 4.3. Variation between the sexes .................................................................................... 68 4.4. Dimensions obtained on facial features .................................................................. 68 4.4.1. Orbital and ocular measurements ................................................................... 68 4.4.2. Nasal Measurements ....................................................................................... 78 4.4.3. Oral measurements ......................................................................................... 81 4.4.4. Auricular measurements.................................................................................. 88 5. Discussion................................................................................................................ 97 5.1. Intra- and inter-observer repeatability .................................................................... 97 5.2. Orbital and ocular dimensions ................................................................................. 98 5.3. Nasal dimensions .................................................................................................... 103 5.4. Oral measurements and relationships ................................................................... 103 5.5. Auricular dimensions .............................................................................................. 105 5.6. Limitations and shortcomings ................................................................................ 106 5.6.1. Sample size..................................................................................................... 106 5.6.2. Inter-observer correlations ............................................................................ 107 5.6.3. Individual features ......................................................................................... 107 6. Conclusion ............................................................................................................. 109 7. References............................................................................................................. 111 Appendix A ............................................................................................................................ 116 Appendix B............................................................................................................................. 117 Appendix C ............................................................................................................................. 120 iv SUMMARY Identification of unknown individuals remains a challenge in the South African context. When it is not possible to identify the unknown individual with primary identifiers, e.g. DNA comparisons, forensic facial approximations (FA) are often used. The aim of this study was to evaluate existing guidelines for FA on a sample of black South Africans (BSA). Facial features considered were the eyes, nose, mouth and ears. The study sample consisted of 49 cadavers (38 males and 11 females, mean age 47), 30 computer tomography (CT) scans (23 males, 7 females, mean age 42) and 30 cone beam computer tomography (CBCT) scans (17 males and 13 females, mean age 33) of BSA. Orbital measurements on dissections included the position of the canthi, the diameters and position of the eyeball and the derived height and width of the orbit. Multiplanar level ocular and orbital depth measurements were performed on CT and CBCT scans using MevisLab (www.mevislab.de). The relationship between the features of the anterior nasal spine (ANS) and the shape of the nasal tip was evaluated on dissections. Gerasimov’s two-tangent method for determining the position of the nasal tip was performed on lateral view photographs of the dissected nose. Dental predictors of the width of the mouth and the philtrum were evaluated. Previously published formulae for the prediction of ear length were tested and population specific formulae designed, taking sex and age into consideration. In general, repeatability tests were acceptable apart from those dimensions involving the orbital canal, medial orbital margin and the philtrum. The eyeball was found to be slightly larger than expected, oval-shaped and supero-laterally placed in a rectangular shaped orbit with an eye fissure sloping slightly downwards laterally. A non-projecting nose with a bulbous nasal tip was the most commonly observed, however, no clear association with the features of the ANS was found. The two-tangent method could also not consistently predict the nasal tip position. The cheilia most often corresponded to the canine/first- premolar junction, while the inter-canine width constituted 60%