Simultaneous determination of the nonlinear-elastic properties of skin and subcutaneous tissue in unconfined compression tests

Background/aims: The compressive nonlinear-elastic properties of soft tissues are usually determined using unconfined compression tests. To determine the nonlinear-elastic behavior of skin and subcutaneous tissue using a conventional approach, the skin and subcutaneous tissue had to be separated before testing. Using such an approach, measurement errors may be increased as a consequence of the reduced specimen dimensions and cumulative experimental errors. In the present study, we propose a novel method to determine the nonlinear-elastic behaviors of the skin and the subcutaneous tissue simultaneously using specimens of skin/subcutaneous composites.

Methods: The stress/strain curves of skin and subcutaneous tissues are derived from stress/strain curves of soft tissue specimens with different skin/subcutaneous height ratios. There is no need to separate the skin from the subcutaneous tissue in the tests, thereby improving the reliability and reducing measurement errors. In order to demonstrate the application of the proposed approach, unconfined compression tests with skin/subcutaneous tissues collected from the front paws of pigs were conducted.

Results/Conclusion: Using the proposed approach, stress/strain relationships of the skin and the subcutaneous tissue were derived from data determined in eight unconfined compression tests. The obtained stress/strain curves were consistent with published experimental data. Compared with conventional methods, the proposed approach is not only more efficient but also more reliable.