Kano Tetsuya, Oritani Shigeki, Michiue Tomomi, Ishikawa Takaki, Hishmat Asmaa Mohammed, Sogawa Nozomi, Inamori-Kawamoto Osamu, Maeda Hitoshi
Department of Legal Medicine, Osaka City University Medical School, Asahi-machi 1-4-3, Abeno, Osaka 545-8585, Japan.
Department of Legal Medicine, Osaka City University Medical School, Asahi-machi 1-4-3, Abeno, Osaka 545-8585, Japan; Forensic Autopsy Section, Medico-legal Consultation and Postmortem Investigation Support Center, Department of Legal Medicine, Osaka City University Medical School, Asahi-machi 1-4-3, Abeno, Osaka 545-8585, Japan.
Leg Med (Tokyo). 2015 May;17(3):167-71. doi: 10.1016/j.legalmed.2014.12.009. Epub 2015 Jan 3.
Major human sex differences in the mandible after adolescence include the overall size as well as the shape of the chin and mandibular angle; however, objective interpretation of discrimination accuracy is difficult for these morphological indicators. The present study investigated measurements of the mandible for sex discrimination using postmortem CT morphometry in forensic autopsy cases of Japanese subjects after adolescence (age>16 years; male, n=116, and female, n=106), including the proposal of novel parameters representing the overall mandibular size and shape. The distance between the gnathion and condylus (gn-cdl), and bigonial width (go-go), as well as the angle formed by bilateral gn-cdl lines (Agn-cdl), correlated with bicondylar breadth (cdl-cdl), independent of the body height, showing no significant sex difference. The distance from the gn to the cdl-cdl line (oblique length), the ratio of Agn-cdl to cdl-cdl, and the oblique triangular area formed by bilateral gn-cdl and cdl-cdl lines (Δobl), which were proposed as indicators of chin protrusion, showed significant sex differences (p<0.001). Overall sensitivity and specificity at respective discriminating points for sex estimation were 0.72 and 0.78 at 105.0mm for the oblique length, 0.73 and 0.83 at 0.49 for the Agn-cdl to cdl-cdl ratio, and 0.82 and 0.78 at 643 mm(2) for Δobl; the efficacy for females was greater in younger subjects. Although these parameters weakly depended on the body height (p<0.0001), the correlations were insufficient for stature estimation. These findings suggest the efficacy of CT morphometry of the mandible for sex discrimination with quantitative assessment.
青春期后人类下颌骨的主要性别差异包括整体大小以及下巴和下颌角的形状；然而，对于这些形态学指标，很难对判别准确性进行客观解释。本研究在日本青春期后（年龄>16岁；男性，n = 116，女性，n = 106）的法医尸检案例中，使用死后CT形态测量法研究了下颌骨的性别判别测量，包括提出代表下颌骨整体大小和形状的新参数。颏下点与髁突之间的距离（gn-cdl）、下颌角间宽（go-go）以及双侧gn-cdl线形成的角度（Agn-cdl），与髁间宽度（cdl-cdl）相关，且与身高无关，无显著性别差异。作为下巴突出指标提出的从颏下点到cdl-cdl线的距离（斜长）、Agn-cdl与cdl-cdl的比值以及由双侧gn-cdl和cdl-cdl线形成的斜三角形面积（Δobl），显示出显著的性别差异（p<0.001）。在性别估计的各个判别点，斜长在105.0mm处的总体敏感性和特异性分别为0.72和0.78，Agn-cdl与cdl-cdl比值在0.49处为0.73和0.83，Δobl在643mm²处为0.82和0.78；在较年轻的受试者中，这些参数对女性的判别效力更大。尽管这些参数与身高有较弱的相关性（p<0.0001），但相关性不足以用于身高估计。这些发现表明，下颌骨的CT形态测量法在性别判别定量评估方面具有有效性。
