Related Experiment Video
Updated: Jun 16, 2026
06:16
A Probing Device for Quantitatively Measuring the Mechanical Properties of Soft Tissues during Arthroscopy
Published on: May 1, 2020
Measuring the quasi-static Young's modulus of the eardrum using an indentation technique
S Mohammad Hesabgar1, Harry Marshall, Sumit K Agrawal
1Department of Electrical and Computer Engineering, The University of Western Ontario, London, Ont, Canada. shesabga@uwo.ca
Hearing Research
|February 12, 2010
Summary
This study estimates the eardrum
Area of Science:
- Biomechanics
- Biomaterials Science
- Medical Imaging
Background:
- Accurate estimation of the eardrum's quasi-static Young's modulus is crucial for developing precise finite-element models.
- Existing literature presents a range of values for eardrum stiffness, necessitating refined measurement techniques.
Purpose of the Study:
- To adapt a tissue indentation technique combined with inverse finite-element analysis for estimating the Young's modulus of the eardrum.
- To determine the Young's modulus of rat eardrums, specifically the pars tensa, using a subject-specific modeling approach.
Main Methods:
- Indentation testing was performed on seven rat eardrums in situ using a custom-built apparatus.
- Subject-specific finite-element models were constructed based on measured unloaded eardrum shapes.
- Inverse finite-element analysis was employed to optimize the Young's modulus by matching simulation results to experimental data.
Main Results:
- An average Young's modulus of 21.7 ± 1.2 MPa was estimated for the pars tensa, assuming a 12 µm thickness.
- The estimated Young's modulus falls within the range reported in existing literature.
- The technique's sensitivity analysis indicated it is primarily influenced by pars tensa thickness, not pars flaccida or manubrium stiffness.
Conclusions:
- The adapted tissue indentation and inverse finite-element analysis provide a viable method for estimating eardrum Young's modulus.
- The study provides a specific Young's modulus value for the rat pars tensa, contributing to biomechanical modeling data.
- The method's robustness to variations in other eardrum structures suggests its potential for reliable stiffness estimation.
Related Concept Videos
01:16Dynamic Modulus of Elasticity of Concrete
The dynamic modulus of elasticity assesses how a concrete structure deforms under impact or dynamic loads. It is typically higher than the static modulus of elasticity, measured under slow, steady loading conditions.
The sonic test is a common method to determine the dynamic modulus. In this test, a concrete beam, sized either 6 x 6 x 30 inches or 4 x 4 x 20 inches, is clamped at its center. Vibrations are initiated at one end of the beam by an electromagnetic exciter unit powered by a...
The sonic test is a common method to determine the dynamic modulus. In this test, a concrete beam, sized either 6 x 6 x 30 inches or 4 x 4 x 20 inches, is clamped at its center. Vibrations are initiated at one end of the beam by an electromagnetic exciter unit powered by a...
01:15Strain and Elastic Modulus
The quantity that describes the deformation of a body under stress is known as strain. Strain is given as a fractional change in either length, volume, or geometry under tensile, volume (also known as bulk), or shear stress, respectively, and is a dimensionless quantity. The strain experienced by a body under tensile or compressive stress is called tensile or compressive strain, respectively. In contrast, the strain experienced under bulk stress and shear stress is known as volume and shear...
01:17Sound as Pressure Waves
Sound waves, which are longitudinal waves, can be modeled as the displacement amplitude varying as a function of the spatial and temporal coordinates. As a column of the medium is displaced, its successive columns are also displaced. As the successive displacements differ relatively, a pressure difference with the surrounding pressure is created. The gauge pressure varies across the medium.
The pressure fluctuation depends on the difference in displacements between the successive points in the...
The pressure fluctuation depends on the difference in displacements between the successive points in the...
01:09Deriving the Speed of Sound in a Liquid
As with waves on a string, the speed of sound or a mechanical wave in a fluid depends on the fluid's elastic modulus and inertia. The two relevant physical quantities are the bulk modulus and the density of the material. Indeed, it turns out that the relationship between speed and the bulk modulus and density in fluids is the same as that between the speed and the Young's modulus and density in solids.
The speed of sound in fluids can be derived by considering a mechanical wave propagating...
The speed of sound in fluids can be derived by considering a mechanical wave propagating...
01:27Measurements of Strain
Strain quantifies the deformation of a material under force, typically measured as normal strain, which represents the change in length when compared with the original length. Electrical strain gauges are used for enhanced accuracy. These devices consist of a conductive wire mounted on a paper backing that adheres to the material's surface. These gauges operate on the piezoresistive effect, where the wire's electrical resistance changes in response to mechanical deformation. The strain gauge...
01:20Elasticity in Concrete
Upon subjecting concrete to moderate or high uniaxial compressive or tensile stresses, the strain response is non-linear relative to the stress applied. As the stress is removed, the resulting stress-strain curve deviates from the original path traced during loading, creating a hysteresis loop, indicative of the concrete's non-linear and non-elastic properties. Typically, a material's modulus of elasticity, which is a measure of the material's stiffness, is inferred from the linear portion of...