投弹致肱骨螺旋骨折的形态特征及生物力学意义

Characteristics of the humeral spiral fractures caused by grenade throwing and its biomechanical impli-cations

目的研究士兵投弹所致的肱骨螺旋骨折的X线特征。方法分析46例肱骨投弹骨折X片,测量骨折部位、长度、斜面角度和骨折的螺旋弧度等形态指标。结果46例骨折均发生于肱骨中下段。远近段骨折线均为螺旋形,具有对称性。骨折长度均在30mm以上,以51mm～90mm最多,共31例(67.4%)。骨折端斜面角度均≤45°,其中40°～45°42例(91.3%)。骨折螺旋角度在285°～326°,平均305.5°(0.85个圆周)。4例在骨折端内侧有一螺旋蝶形骨片。结论投弹骨折按形态特征分为3种类型,主要发生于上臂加速期,由扭转暴力和纵轴压缩力引起。

Objective To investigate the X-ray characteristics of humeral spiral fracture cau sed by hand grenade throwing.Methods Forty-six soldiers suffered humera l fracture caused by grenade throwin g in military training.Their X-ray film s were evaluated and fracture featur es were measured.Results All fractures involved the mid-distal humeral shaft.The spiral fracture lines were sy mmetrical in the proximal and distal parts.The lengths of fractures were above 30mm,with 51～90mm in 31cases(67.4%).All fracture angles were less than 45°,with 40°～45°in 42cases(91.3%).The spiral arcs of fractures were 285°～326°with an average of 305.5°(0.85circle).Four cases had a butterfly fracture piece on the medial side.Conclusions Spiral fractures due to grenade thro wing mainly occur at the acceleratio n phase of throwing,and are mainly caused by the combination of torsion al and compressive forces.Humeral t hrowing fractures are characterize d by long fracture line,sharp fracture a ngle,and large spiral arc.