Mbonani Thandolwethu Mbali, L'Abbé Ericka Noelle, Ridel Alison Fany
University of Pretoria, Department of Anatomy, Faculty of Health Sciences, Tswelopele Building, Private Bag X323, Prinshof 349-Jr, Pretoria 0084, South Africa.
Forensic Sci Int. 2024 Dec;365:112282. doi: 10.1016/j.forsciint.2024.112282. Epub 2024 Oct 30.
Variable growth patterns and multifactorial mechanisms cause variation in facial shape. These differences in facial morphology pose challenges for craniofacial reconstruction. Three-dimensional (3D) imaging modalities are a valuable resource for examining these variations. In this study, we used geometric morphometric methods to evaluate the effects of population affinity, sex, age, and allometry on the variation and covariation of hard and soft tissue facial morphology matrices in a sample of French and white South African individuals. Seventy-six and 108 cone-beam computed tomography scans of white South African and French nationals, respectively, were retrospectively acquired. Three-dimensional anatomical structures (hard and soft tissue matrices) were extracted using MeVisLab© v. 2.7.1 software for dense landmarking of 43 craniometric, 50 capulometric, and 559 sliding landmarks. Geometric morphometric analyses were used to quantify shape differences attributed to population affinity, sex, age, and allometry and assess the covariation between hard tissue structures and soft facial tissues. Hard and soft tissue facial matrices were influenced by population differences, sexual dimorphism, and aging. Compared to sex and age, population affinity had the strongest influence on variation. In French individuals, all hard and soft tissue matrices were sexually dimorphic, except for the eyes and left external auditory meatus (EAM). In white South Africans, sexual dimorphism was observed for the mouth, midface, and left EAM. Significant shape differences were also observed for specific age groups. The underlying skull and overlying soft tissues were strongly associated with the nose and anterior nasal aperture (correlation, r-PLS = 0.976), followed by the right ear and right EAM (r-PLS = 0.875) and the left ear and left EAM (r-PLS = 0.871) in white South Africans. For French individuals, relatively weak to moderate correlations were observed, and the covariation between matrices was nonsignificant, except for the association between the right ear and right EAM (r-PLS = 0.499). The smallest covariation was observed between the mouth and midfacial matrix in both populations (South African: r-PLS = 0.464; French: r-PLS = 0.367), which was also nonsignificant. This study revealed that 3D imaging technology and geometric morphometric methods can accurately quantify and visualize facial morphology differences. These methods can also evaluate the association between skull structure and soft facial features.
面部生长模式的多样性和多因素机制导致面部形状存在差异。这些面部形态学上的差异给颅面重建带来了挑战。三维（3D）成像方式是研究这些差异的宝贵资源。在本研究中，我们使用几何形态测量方法，评估了人群亲缘关系、性别、年龄和异速生长对法国人和南非白人样本中硬组织和软组织面部形态矩阵的变异和协变的影响。我们分别回顾性获取了108例法国人和76例南非白人的锥束计算机断层扫描图像。使用MeVisLab© v. 2.7.1软件提取三维解剖结构（硬组织和软组织矩阵），对43个颅骨测量标志点、50个帽状测量标志点和559个滑动标志点进行密集地标标注。采用几何形态测量分析来量化归因于人群亲缘关系、性别、年龄和异速生长的形状差异，并评估硬组织结构与面部软组织之间的协变。硬组织和软组织面部矩阵受人群差异、性别二态性和衰老的影响。与性别和年龄相比，人群亲缘关系对变异的影响最为强烈。在法国人中，除眼睛和左侧外耳道外，所有硬组织和软组织矩阵均存在性别二态性。在南非白人中，口部、中面部和左侧外耳道存在性别二态性。在特定年龄组中也观察到了显著的形状差异。在南非白人中，颅骨基础结构和覆盖其上的软组织与鼻子和前鼻孔密切相关（偏最小二乘相关系数，r-PLS = 0.976），其次是右耳和右侧外耳道（r-PLS = 0.875）以及左耳和左侧外耳道（r-PLS = 0.871）。对于法国人，观察到的相关性相对较弱至中等，除了右耳和右侧外耳道之间的关联（r-PLS = 0.499）外，矩阵之间的协变不显著。在两个人群中，口部和中面部矩阵之间的协变最小（南非人：r-PLS = 0.464；法国人：r-PLS = 0.367），且也不显著。本研究表明，3D成像技术和几何形态测量方法能够准确量化并可视化面部形态差异。这些方法还可以评估颅骨结构与面部软组织特征之间的关联。
