Saternus K-S, Maxeiner H, Kernbach-Wighton G, Koebke J
Institute of Legal Medicine Kassel, Germaniastr. 7, D-34119 Kassel, Germany.
Leg Med (Tokyo). 2013 May;15(3):134-9. doi: 10.1016/j.legalmed.2012.10.008. Epub 2012 Dec 20.
It appears still questionable whether fractures to the superior thyroid horns can be used for forensic reconstruction purposes regarding the functional mechanism causing compression of the neck soft tissues. Localisations and types of such fractures were documented in 118 cases of superior thyroid horn fractures caused by suicidal hanging. The placement of the ligature was above the larynx in 109 cases and in the remaining nine cases across the thyroid cartilage. As a secondary parameter the degree of ossification of thyroid cartilages and superior horns was used. Bone densities of typical cases (equidensities) were measured radiologically. Additionally, dummy tests were performed focused on two extreme shapes of superior thyroid horns to assess stress peaks using resin dummies and polarised light. Such peaks were located in the lower thirds of the horns close to their bases. With the larynx still cartilaginous, the base appears a typical location for fractures caused by suicidal hanging. An ossification pattern defined as "type 1" showed broad and osseous superior thyroid horns. If ossification was homogenous, fractures were located at the sites of maximum mechanical stress. In case of inhomogenous ossification, being the more common mode, the horn bases were more resistant to pressure and bending so that no fractures occurred. They were instead located at the sites of the greatest differences in density and distributed in an apparent random pattern. Narrow and deep insertions of the superior thyroid horns at the back surface of the upper thirds of the thyroid cartilages (posterior aspects) were classified as "type 2" ossification. Upon flexion, the long horns came into contact with the upper edges of the dorsal aspect creating a torque. Further flexion from an increasing impact by the ligature extended the long lever arm causing the base of the upper thyroid horn being broadly torn out of the dorsal aspect. The results suggest that localisations of fractures to the superior thyroid horns in connection with ossification patterns may be helpful for the reconstruction in suicidal hanging regarding the mechanics of the ligature in relation to its position around the neck.
就导致颈部软组织受压的功能机制而言，甲状腺上角骨折是否可用于法医重建目的，目前仍存在疑问。在118例自杀性缢吊所致的甲状腺上角骨折病例中，记录了此类骨折的位置和类型。109例中绳索位于喉部上方，其余9例绳索跨过甲状软骨。作为次要参数，使用了甲状软骨和上角的骨化程度。对典型病例（等密度）的骨密度进行了放射学测量。此外，针对甲状腺上角的两种极端形状进行了模拟测试，使用树脂模型和偏振光来评估应力峰值。此类峰值位于角的下三分之一靠近底部处。在喉部仍为软骨状态时，底部似乎是自杀性缢吊所致骨折的典型部位。定义为“1型”的骨化模式显示甲状腺上角宽阔且骨质化。如果骨化均匀，骨折位于最大机械应力部位。在骨化不均匀的情况下（这是更常见的模式），角的底部对压力和弯曲更具抵抗力，因此不会发生骨折。相反，骨折位于密度差异最大的部位，并呈明显随机分布。甲状腺上角在甲状软骨上三分之一后表面（后部）的狭窄且深陷的插入被归类为“2型”骨化。屈曲时，长角与背侧上缘接触产生扭矩。随着绳索施加的冲击力增加进一步屈曲，延长的长杠杆臂导致甲状腺上角底部从背侧广泛撕裂。结果表明，与骨化模式相关的甲状腺上角骨折位置，可能有助于在自杀性缢吊案件中根据绳索围绕颈部的位置重建其力学机制。
