The shoulder dynamic response to lateral and oblique impacts was investigated by submitting Post Mortem Human Subjects (PMHS) to three non-injurious impacts delivered on the right shoulder by a rigid guided impactor (m=23.4 kg, v=1.5 m/s) at three different impact angles in the horizontal plane (0°, +15°, -15°). Then, the injury response was investigated with a single injurious lateral impact (m=23.4 kg, v=4 to 6 m/s) on the left shoulder. Triaxial accelerometers and photographic markers were positioned on different shoulder bone locations providing means of 3D response analysis. For all impact directions, the acromion, closest point to the impact, recorded the highest acceleration levels. Different impact force and acceleration signal shapes were obtained depending on impact directions. In terms of deflection, an average of 30 mm and 60 mm of maximum shoulder deflections were measured respectively for non-injurious and injurious impacts. Injurious tests produced fracture to the clavicle but also to the scapula.
Keywords:
Biomechanics; cadavers; shoulder; impactors; side impacts