摘要
选择胸椎骨折固定器需要了解肋骨的力学特性。本文对正常国人青年和老年尸体肋骨进行扭转实验,并对比分析青年和老年尸体肋骨的扭转力学特性,为临床提供生物力学参数。实验标本取自4具正常国人男性新鲜尸体肋骨,年龄分别为23岁、27岁、72岁、76岁,根据年龄分为青年组和老年组。以肋骨标本沿纵向切成长55 mm的样本试样,每组各20个。实验环境温度为20℃,将样本两端装夹于扭转试验机的夹头内,以1°/s的扭转速度对试样施加扭矩,测试样本破坏后的最大扭矩和最大扭转角值,并计算其扭转切应力,同时观察样本破坏断口的形貌。实验结果表明,青年组肋骨最大扭矩、切应力和扭转角均大于老年组,有显著性差异(P<0.05),因此青年组和老年组肋骨具有不同的扭转力学特性。样本断口形貌显示,2组样本断口多数为斜型,少数为横型。大体观察,青年组肋骨骨小梁排列细密,老年组肋骨骨小梁排列稀疏,具有老年骨质疏松的特征。
The choice of the thoracic spine fracture fixation needs to recognize the torsional parameters of fibs. In this paper, we carried on the torsional experiment to the normal youth and the old fresh corpse ribs for analyzing their torsional properties and providing the biomechanies parameter in clinic. Forty experimental specimens were taken from 4 normal male fresh corpse, aged 23,27,72,76 years old respectively, and slivered into 55ram long longitudinally, The specimens were divided into 2 groups according to age, each group of 20 specimens. Under the temperature of 20 ℃, each specimen was nipped to the testing machine and twisted until it was broken at the speed of the 1 ° per second. When the specimen was broken we captured the maximums of torque and torsion angle via the test machine, observed the macroscopic fracture appearance of each specimen. The shear stress of each specimen was following calculated as well. The experimental results proved that the maximum torque, shear stress and torsion angle of youth rib were greater than those of the old with significant differences （ P 〈 0. 05 ）, which means there is difference in torsion property between youth and the old. By macroscopic observation we found that the most of fractured surfaces showed slanting and less horizontal, the bone trabecula of youth rib arranged closely, the old＇ s arranged sparsely, which are some features of senile osteoporosis.
出处
《北京生物医学工程》
2011年第4期412-414,419,共4页
Beijing Biomedical Engineering
关键词
年龄
肋骨
扭矩
扭转角
切应力
age
rib
torque
angle of torsion
shear stress
