Kemper Andrew R, McNally Craig, Kennedy Eric A, Manoogian Sarah J, Duma Stefan M
Virginia Tech - Wake Forest Center for Injury Biomechanics.
Stapp Car Crash J. 2008 Nov;52:379-420. doi: 10.4271/2008-22-0016.
The purpose of this study was to investigate the influence of arm position on thoracic response and injury severity in side impacts. A total of sixteen non-destructive side impact tests and four destructive side impact tests were preformed using four human male cadavers. Single-axis strain gages were placed on the lateral and posterior regions of ribs three through eight on the impacted side, and the lateral region of ribs three through eight on the non-impacted side. Thoracic rods attached to ribs five, seven, and nine were used to measure lateral rib deflection. For the non-destructive tests, four test conditions with different arm positions were evaluated for each cadaver by performing displacement-controlled, low-energy, lateral impacts, 16 kg at 3 m/s, with a pneumatic impactor. The results of these tests showed that the highest average peak forces, peak rib deflections, and peak rib strains were observed when only the ribs were impacted and lowest when the shoulder was impacted. In addition, higher average peak forces, peak rib deflections, and rib strains were observed when the arm was placed parallel with the thorax versus 45 degrees. For the destructive tests, two test conditions were evaluated by performing high-energy lateral impacts, 23.4 kg at 12 m/s, with a pneumatic impactor. Only one destructive test was performed per cadaver with the arm placed at either 45 degrees or parallel with the thorax. Using rib fractures as the parameter for AIS, both tests conducted with the arm at 45 degrees resulted in an AIS = 4 due to the large number of ribs with multiple fractures which resulted in a flail chest. Conversely, both tests conducted with the arm parallel with the thorax resulted in an AIS=3. The analysis of thoracic strain gage time histories showed that, in general, the rib fracture timing varied with respect to thoracic region. Using scaled rib 5 deflection, lateral fractures on the impacted side occurred between 4.2 mm and 34.9 mm, posterior fractures on the impacted side occurred between 19.0 mm and 37.8 mm, and lateral fractures on the non-impacted side occurred between 60.2 mm and 74.3 mm of deflection. It was found that AIS = 1 injuries occurred at scaled rib deflections of 4.2 mm to 8.6 mm (2% to 3% compression), AIS = 2 at 9.6 to 17.4 mm (4% to 7% compression), and AIS = 3 at 13.1 mm to 20.1 mm (5% to 9% compression) measured at rib five. In conclusion, the results of the current study show that in low-energy side impacts both the arm and shoulder reduce impactor force, rib deflection, and rib strain. In high-energy side impacts, the position of the arm has a considerable effect on both the total number and distribution of rib fractures.
本研究的目的是调查手臂位置对侧面碰撞中胸部响应和损伤严重程度的影响。使用四具男性人体尸体进行了总共16次非破坏性侧面碰撞试验和4次破坏性侧面碰撞试验。单轴应变片被放置在受撞击侧第三至八根肋骨的外侧和后侧区域，以及未受撞击侧第三至八根肋骨的外侧区域。连接到第五、七和九根肋骨的胸部杆用于测量肋骨的侧向位移。对于非破坏性试验，通过使用气动冲击器进行位移控制的低能量侧向冲击（3米/秒时16千克），对每具尸体评估四种不同手臂位置的试验条件。这些试验结果表明，仅肋骨受撞击时观察到的平均峰值力、峰值肋骨位移和峰值肋骨应变最高，而肩部受撞击时最低。此外，与手臂与胸部成45度角相比，手臂与胸部平行放置时观察到更高的平均峰值力、峰值肋骨位移和肋骨应变。对于破坏性试验，通过使用气动冲击器进行高能量侧向冲击（12米/秒时23.4千克）评估两种试验条件。每具尸体仅进行一次破坏性试验，手臂放置在45度角或与胸部平行的位置。以肋骨骨折作为损伤严重程度评分（AIS）的参数，在手臂呈45度角进行的两次试验中，由于大量肋骨多处骨折导致连枷胸，结果AIS = 4。相反，在手臂与胸部平行进行的两次试验中，结果AIS = 3。胸部应变片时间历程分析表明，一般来说，肋骨骨折时间因胸部区域而异。使用缩放后的第五根肋骨位移，受撞击侧的外侧骨折发生在位移4.2毫米至34.9毫米之间，受撞击侧的后侧骨折发生在位移于19.0毫米至37.8毫米之间，未受撞击侧的外侧骨折发生在位移60.2毫米至74.3毫米之间。发现AIS = 1的损伤发生在缩放后的肋骨位移为4.2毫米至8.6毫米（2%至3%压缩）时，AIS = 2发生在9.6至17.4毫米（4%至7%压缩）时，AIS = 3发生在第五根肋骨处测量的位移为13.1毫米至20.1毫米（5%至9%压缩）时。总之，当前研究结果表明，在低能量侧面碰撞中，手臂和肩部均可降低冲击器力、肋骨位移和肋骨应变。在高能量侧面碰撞中，手臂位置对肋骨骨折的总数和分布均有相当大的影响。
