1. MIDDLE EAST TECHNICAL UNIVERSITY MECHANICAL ENGINEERING DEPARTMENT ME 590 SEMINAR Prepared by : Osman KILIÇ Supervisors : Prof. Dr. Turgut TÜMER Asst. Prof. Ergin TÖNÜK Thesis Subject: “BIOMECHANICAL MODELLING OF HUMAN HAND”

2. ANATOMY OF THE WRIST BONES JOINTS

3. VOLAR (PALMAR) LIGAMENTS DORSAL LIGAMENTS

4. FUNCTIONS OF THE WRIST FLEXION EXTENSIONRADIAL DEVIATION ULNAR DEVIATION

5. SURGICAL & PATHOLOGICAL ASPECTS OF THE WRIST MODEL Changes in load distribution between carpal bones is very important for implant applications, surgical operations and ligament tears.

6. Pathological Example: Extra loading on Lunatum bone due to abnormal contact structure between Capitate and Lunate. Capitate Lunate Scaphoid Capitate Lunate Scaphoid Cup shaped part of the Capitate is shaved to remove extra load on Lunate.

7. IN LITERATURE Kinematics of wrist bones are not studied as a whole structure. Instead, there are studies containing a few bones which generally focus on contact forces and relative motion observations.

8. Recent studies are about finite element modelling of wrist bones. In all these models, most of the bones, ligaments and joints are missing. In order to have high a fidelity model of the wrist; bones, ligaments and joints should be studied as a whole. Radius

9. THESIS STUDIES 3D wrist bone models are taken from anthropometric database of ADAMS /Lifemodeler: Sex : Male Age : 360 months Height: 1778 mm Weight: 77 kg The wrist is modeled by using Msc. ADAMS software.

10. BONES

11. Motion Analysis of the Wrist Bones SPINNING ROLLING SLIDING

12. Contacts and jonts between the wrist bones are analyzed Joints are taken as spherical joints.

13. JOINT-LIGAMENT-CONTACT MODEL

14. LIGAMENTS Stiffness Coefficient Damping Coefficient

15. 52 different ligaments with different stiffness and damping coefficients are used in the model

16. JOINTS BUSHING ELEMENTS In the model, rotational spring and damper coefficients are ~1% of translational spring and damper coefficients. 20 bushing elements (joints) are used in the model (Coordinates are local coordinates of the bushing elements)

17. CONTACT e > 1  stiffening stiffness e < 1  softening stiffness Penetration distance

18. JOINT-LIGAMENT-CONTACT STRUCTURE

19. FLEXION MOTION

20. EXTENSION MOTION The model gives correct results for flexion but for extension limit is exceeded

21. RADIAL DEVIATION MOTION

22. ULNAR DEVIATION MOTION

23. AXIAL LOADING

24. ~50% ~30%~20% ~60% ~20%

25. CONCLUSION & FUTURE WORK For flexion, extension, radial and ulnar deviation motions a different analysis and a model will be developed Joint and ligament variables (stiffness & damping coefficients) will be revised for each different model Surface discontinuities on the bones causes errors in the results More accurate bone structures will be taken from CT data