Response of the sternum under dynamic 3-point bending - biomed 2010

The goal of this study was to investigate the response and failure properties of the human sternum under bending loading. Nine sternum specimens from post mortem human surrogates (n=7 male, n=2 female, age: 62.7 +/- 10.9 years) were extracted and potted in a three point bending test setup. Specimens were loaded to failure at their center points in bending at 1100 mm/s, with some specimens previously loaded in a non-failure quasi-static loading test. In two cases, the non-failure test was repeated to show that specimens were not damaged during non-failure testing. The sternum specimens were found generally to be unable to support shear forces in the anterior-posterior direction and as a result had relatively low failure moments (24.1 Nm +/- 20.1 Nm). While two of the specimens did fail in bending, the remaining specimens failed as a result of the high tensile forces introduced by the bending loads. These specimens first experienced compressive loads, and then, as the potted ends continued to rotate, tensile loads, which resulted in failure of the specimens (400-800 N).