静止站立位正常骨盆的生物力学研究

目的通过测试正常骨盆在静止站立位时生物力学指标,在理论上为骨盆骨折的治疗提供生物力学依据。方法随机从30具甲醛固定骨盆标本中取出8具(其中男女各4具;年龄27～50岁,平均36.5岁)。将骨盆置于生物力学实验机上,模拟人体站立姿势,利用应变式测力传感器测试静止站立位时正常骨盆不同部位的的应变、位移、极限载荷、屈服点载荷数值。结果①静止站立位时,在骨盆环结构中,骶髂关节附近承载压应力最大,髂骨翼作用附近承载压应力最小;且骶骨、骶髂关节、弓状线等后环结构主要承载压应力,耻骨上、下支、耻骨联合主要承载张应力。②除去腰椎间盘等软组织结构,骶髂关节下部的应变最大。③骨盆受压时出现弹性形变和塑性形变现象,在弹性形变区间范围内,骨盆所受载荷大小与自身变形程度成正比,消除载荷后骨盆能基本复原,且骨盆的力学强度无明显变化。超过骨盆的弹性形变上限(屈服点),骨盆处于塑性形变,则很难复原,力学强度明显下降。④男性标本的屈服点载荷均值为2860N,极限载荷3600N;女性标本的屈服点载荷均值为2473N,极限载荷均值为3175N。⑤所有骨盆标本在连续多次弹性形变区间范围内载荷作用下各点应变值相差较小,说明不同骨盆的整体弹性模量无明显差异。结论骶髂关节等后环结构主要承载压应力,耻骨上、下支及耻骨联合等主要承载张应力,骶髂关节等后环结构对于维持垂直应力下骨盆环的稳定性至关重要。

Biomechanical Studies of Normal Pelvis in Static Standing Position

Objective To provide the basis of biomechanics for the clinical pelvis fracture theoretically by testing the biomechanical data of the normal pelvis in the static standing position.Methods Primarily,8 over 30 adult pelvis specimens were randomly collected which were preserved in formalin,of which 4 were male and the others were female.All the specimens were from 27 to 50 years old and the average of 36.5 years old.Then put those specimens which were imitating normal standing position of human beings on biomechanics testing machine.And use mechanical sensor to test pelvis' figure of stress change,position displacement,ultimate load and breakdown load.Results According to the research,some results were shown.Firstly,in static standing position of the pelvic ring,different parts afforded different stress.The most of compression stress had been afforded by the zone of sacroiliac joint and the iliac wing just afforded the lowest.Additional sacrum,sacroiliac joint,arcuate line bore the compression stress and ramus of pubis,articulation of pubis bore the tensile stress.Secondly,the lower part of the sacroiliac joint bore the greatest strain except the disc and other soft tissue structure.Thirdly,when pelvis was squeezed,the phenomenon of elastic deformation and plastic deformation was shown.When it was compressed repeatedly in the range of flexibility,the pelvic load and its deformation were in direct proportion,and the mechanical strength of the pelvis would not significantly change.Once over the scope of this range,pelvis would not recover,and mechanical strength declined apparently.Fourthly,the average transmutative load of male specimens was 2 860 N and breakdown load was 3 600 N.The average transmutative load of females specimens was 2 473 N and breakdown load was 3 175 N.Fifthly,it had been tested that pelvis could still recover formerly altitude after series continuous load.It showed that the whole pelvis' flexibility simulation was not significantly changed.Conclusion In the structure of the pelvic ring,different parts afford different stress,such as sacrum,sacroiliac joint,arcuate line bear the compression stress and ramus of pubis,articulation of pubis bear the tensile stress.The research shows that sacroiliac joint and other posterior ring structure are the key element to keep whole pelvis stabilization under vertical stress.