Abstract
In order to achieve a recognisable depiction of the face in life, a sound knowledge of craniofacial skeletal and muscular anatomy is crucial. This is because the relationships between the musculature and underlying bony architecture contribute significantly to the uniqueness of each individual face. The aim of this study is to improve the scientific validity of all three phases of forensic craniofacial reconstruction (CFR): (i) the average soft tissue depth (ASTD) pattern, (ii) naso labial soft tissue estimation, and (iii) facial musculature estimation/reconstruction with particular emphasis on the origin of a muscle that helps define the shape of the cheeks, the zygomaticus major muscle.This study adopted a combined method approach by performing a systematic review, cephalometric and computed tomography (CT) analysis, as well as a dissection study. In addition, this thesis explored the accuracy of the published methods in nose estimation applied to German, Scottish and Indonesian ancestral groups. Overall, this study identified several findings which are discussed in a series of chapters. These findings are:
(i)ASTD pattern: (a) A systematic review found that ancestry has a small effect towards the ASTD. However, a meta-analysis inferred that class of malocclusion influenced the tissue depth significantly in the upper lip, stomion and lower lip. The visible general pattern of ASTD was that class III skeletal pattern has the deepest soft tissue of the 3 classes in the upper lip and vice versa for lower lip. Class II skeletal pattern was at the opposite end of the spectrum, with the thinnest upper lip and deepest tissue at lower lip. (b) The ASTD study in the Scottish subadult population found sexual dimorphism only on upper lip thickness. Following age progression, ASTD showed both an increase and decrease in tissue depth. However, tissue depth differences with age or sex were not statistically significant. In the Indonesian adult population, significant sexual dimorphism was detected in midline soft tissue depth from the nasion down to the lower lip. Although in Scottish and Indonesian populations and both genders, the ASTD general pattern as described above was seen, no systematic pattern was detected.
(ii)Naso labial soft tissue estimation: (a) Nose width and nasal aperture in a German population revealed significant sexual dimorphism. Two published nose width estimation methods were compared to the actual nose width values. Intraclass Correlation Coefficient (ICC) levels found that the accuracy of the Gerasimov method was slightly superior to the Krogman and Iscan method when applied to this population. In addition, three types of derived method (linear regression, subtraction, and ratio) were generated specifically for the German adult population. (b) The published nose profile estimation method by Rynn et al. (2010) performed well when applied to the Scottish subadult nose profile. However, a degree of deviation was detected when the published method was applied to the Indonesian adult population. Therefore, derived methods in estimating nose profile were created through linear regression specifically for the Indonesian adult population.
(iii) Facial musculature estimation/reconstruction with particular emphasis on the origin of the zygomaticus major muscle: using the Thiel embalmed cadaver dissection method, this study discovered that the zygomaticus major muscle origin point was located on the surface of the zygomatic arch, in proximity and posterior inferior to the zygomatic angle.
The findings from all 3 phases of the forensic CFR study have brought new insights that serve to improve the accuracy and scientific validity of guidelines in this discipline.
| Date of Award | 2019 |
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| Original language | English |
| Awarding Institution |
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| Sponsors | Ministry of Research, Technology and Higher Education of the Republic of Indonesia |
| Supervisor | Christopher Rynn (Supervisor), Peter Mossey (Supervisor) & Sue Black (Supervisor) |