Abstract
We show that the mechanical properties of the outer covering (or capsule) of pig spleen can be modelled as a nonlinear elastic membrane with an exponential stress-strain Law. Knowledge of the caspule's elastic properties is important for the development of a virtual reality training package for keyhole surgery. Bccause capsule tissue is very fragile and tears when clamped and pulled it is not possible to obtain experimental data for which the usual uniform stretch data-fitting approach can be adoptcd.Instcad we perform experiments in which the capsule deforms non-uniformly and describe how numerical solutions of the corresponding boundary value problem can be fitted to the experimerimental data in order to validate the biomechanical model.