Background: pathological changes in tissue lead to changes in elasticity and stiffness. Strain is deformation of tissue when exposed to pressure. Elasticity is return of tissue to original form when this pressure is removed. Palpation; a clinical method of examination used for thousands of years, is a method to test elasticity and stiffness of tissues. However, palpation is totally subjective and is not suitable for deeper tissues. Elastosonography; a new method to test tissue stiffness. It is suitable for deeper tissue, but it is subjective. Recently, SWE which is objective and quantitative has been developed to test for tissue stiffness.