1. الميكانيكية الاحيائية في جسم الانسان
Biomechanics in
Human Body
الميكانيكية الاحيائية في جسم الانسان

2. Mechanics Mechanics-study of forces and motions for the body. Statics
deal with nonmoving parts (equilibrium).
Dynamics
deal with moving systems
Kinematics
Describes motion and includes consideration of time, displacement, velocity, acceleration and mass.
Kinetics
Describes forces that cause motion of a body

3. Basic Biomechanics
Biomechanics-apply mechanics to the structure and function of the human body.
Is the scientific study of the mechanics of biological systems.

4. Applications Biomechanics
Engineering
(Mechanics)
Anatomy
Physiology
Applications Biomechanics
Improved the performance ( Human movement)
Preventing or treating injury
Design prosthesis & orthosis or artificial limb

5. Biomechanics Biomechanics is be used to:
To understand the biomechanical analysis (motion) (Gait cycle) (for normal and patient human).
To understand function of vascular system in order to analysis the fluid biomechanics (blood flow).
To analysis the biomechanics of :
soft tissue (muscle)
hart tissue (bones).
To model these systems to aid in the design of prosthetic devices (e.g. artificial artery or artificial limb)

6. Principles associated to biomechanical analysis
Balance and stability
Centre of gravity
Elasticity
Forces (action & reaction)
pressure
power
Bending moment
Torque moment
Friction
Wear
Density
Momentum
Velocity
Time
Acceleration
Deceleration
Mass
Inertia
Dimensions
Viscosity
There are far too may to cover in 4- 5 weeks so go back to the context of striking and still there are a lot.

7. Biomechanical principles associated with basic movement patterns
Running
Stopping
forces (action/ reaction)
motion (straight line)
momentum
friction
forces
acceleration and deceleration
Newtons laws
friction

8. General Motion Most movements are combination of both Linear motion
Angular motion
Newton’s First Law
Law of inertia
Newton’s Second Law
Law of Acceleration
Newton’s Third Law
Law of Action and Reaction

9. JOINT REACTION FORCES

10. Loads
The external forces that act on the body impose loads that affect the internal structures of the body.

11. Humans moves through a system of levers There are 3 classes of levers.
First class lever
Second class lever
Third class lever

12. Up and down movement of the head about the atlas joint.
First Class Levers
Up and down movement of the head about the atlas joint.

13. First Class Levers
Using a crowbar to move a rock.

14. First Class Levers
Using a hammer to pull out a nail.

15. First Class Levers
A see-saw.

16. The movement of the foot when walking.
Second Class Levers
The movement of the foot when walking.
(the calf muscle provides the effort and the ball of the foot is the pivot)

17. Second Class Levers
Opening a bottle with a bottle opener

18. Second Class Levers
Pushing a wheel barrow.

19. Third Class Levers
Biceps curl.

20. Levers
The mechanical advantage of levers may be determined using the following equations:
Mechanical advantage =
Resistance Force or
Length of force arm Length of resistance arm

21. Biomechanics of the denture
Bitting Force
Human female bite = 360 N
Human male bite = 564 N
Boxer can punch with 10,528 N 18
Lion bite down with 5,533 N 10
Dog bite = 1,410 N 2.5

22. Fluid biomechanics (blood flow). Vascular Biomechanics
Continuity Equation:
mass in = mass out
Q = ((P1-P2)..R4)/(8.µ.L)
Assumptions
- Laminar Flow
- Newtenian fluid
- Incompressible fluid
- Single phase

23. Atherosclerosis
Blood density
1060 kg/m3
Blood viscosity
kg/m.s

24. Atherosclerosis

25. Velocity Pathlines
Steinman, 2000

26. Wall Shear Stress Contours
Augst et al, 2007
Jamalian Ardakani, 2010
In healthy vessels, tw is low (~ dynes/cm)

27. Velocity Pathlines Model 1 (peak of systole)
Model 1 (peak of diastole)

28. Bone Biomechanics (Hard tissue)
Bone is anisotropic material
(modulus is dependent upon the direction of loading).
Bones are:
strongest in compression.
weakest in shear.
Ultimate Stress at Failure Cortical Bone
Compression < 212 N/m2
Tension < 146 N/m2
Shear < N/m2

29. Mechanical Properties of Bone
Ductile or Brittle
Depends on age and rate at which it is loaded
- Younger bone is more ductile
- Bone is more brittle at high speeds
Following a fracture, ductile material will not conform to original shape after fracture. Brittle will return to original shape after fracture.
return to original shape after fracture

30. Type of Loading Fracture Mechanics Bending Torsion Bending load:
Compression strength greater than tensile strength
Fails in tension
Axial Loading
Compression
Tension

31. Bending of a Long, Solid Bone:
Tension
Compression
Stress Free
in the middle
Bending of a Long, Hollow Bone:
 =M . y / I
Tension
Compression
I = .(R4-r4)/4
Save weight & keep strength:

32. Biomechanics Bone fixation
External
fixation
Internal
fixation

33. Biomechanics of External Fixation
Number of Pins
Two per segment
At least 3 pins

35. Biomechanics of Internal Fixation
IM Nails (Rod)
Stiffness is high proportional to the 4th power.

36. Biomechanics of Internal Fixation
Plate Fixation
Functions of the plate Compression Neutralization Buttress

38. Bending moment = F x D
F = Force
F = Force
IM Nail
Plate D D
D = distance from force to implant
The bending moment for the plate is greater due to the force being applied over a larger distance

39. Biomechanical principles similar to those of external fixators
Stress distribution

40. Osteoarthritis may result from wear and tear on the joint
The medial (inside) part of the knee is most commonly affected by osteoarthritis. 

41. Treatment or Total Knee Replacement
Moving surfaces of the knee are
metal against plastic
UHMWPE

42. Structural Alignment Genu Varum (Bowlegged) Genu Valgum (knock kneed)
Hyperextension

43. Biomechanics of Flat Foot

44. Biomechanics of motion of human body To design artificial lower limb
Gait Cycle
Swing Phase
Stance Phase
Heel Strike
Midstance
Toe off
To design artificial lower limb

45. Ground reaction force (by force plate “platform”)
1.3 W

46. Biomechanics of motion of human body
-Socket alignment
-Static alignment
-dynamic alignment
Hip, knee, and ankle joint centers lie along a common axis.

47. Numerical Study of Prosthetic Socket
(Interface pressure sensor between socket and skin)

48. Numerical Study of Prosthetic Socket

49. Theoretical Part -Stress - Max. Normal Stress - Max. Shear Stress
- Von Mises stress
Deformation
- Linear
- Angular
-Fatigue ratio
-Strain energy
-Failure index
-Safety factor

50. Contours of Deformation Distribution
Contours of Equivalent Von Mises Stress Distribution

51. Thanks you for listening