Biomechanics of Bone Growth and Articulations

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Biomechanics of Bone Growth and Articulations
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Why think about biomechanics of Bones?

• Young Athletes
• Adult Bone Development
• Older Adult Development
• Responsibility for health and safety of
  individuals engaging in movement

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Functions of Bone

• Protect Vital Organs
• Support Soft Tissues
• Factory for making RBCs
• Mineral Reservoir
• Muscle Attachment
• Receive Muscle Forces for Movement

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Bone Composition and Its Relationship to Bone
Stiffness

• Calcium Carbonate, Calcium Phosphate, Collagen,
  Water,
• Calcium Carbonate and Calcium Phosphate
• Compressive Strength
• Collagen
• Tensile Strength Flexibility
• Water
• Some Strength

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Bone Classification

• Short
• Flat
• Irregular
• Long

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Common Landmarks on Bones

• Condyle
• Epicondyle
• Facet
• Foramen
• Fossa
• Process
• Tuberosity

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General Architecture of Bone

• Porosity of Bone
• varies with different bones
• Cortical Bone
• low porosity, but high mineralization
• withstand greater loads but little deformation
• Trabecular (Spongy) Bone
• high porosity
• greater deformation than cortical bone

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Architecture of Long Bones

• Diaphysis
• cortex
• periosteum
• endosteum
• medullary cavity
• Epiphysis
• Articular Cartilage

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Bone Growth

• Longitudinal
• Epiphyseal (Growth) Plate
• Cartilogenous Disc
• Circumferential
• Osteoblasts vs osteoclasts
• Ongoing throughout life
• At tendon attachments
• Apophyseal Plates

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Wolffs Law

• Changes in structure occur according to changes
  in function
• What changes?
• Physical Stress
• compression,tension, torsion, shear
• Mechanical Properties of Bone

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Mechanical Properties of Bone

• Strength
• Elasticity
• Stress (Force) - Strain (Deformation)
  Relationship
• Rate of Force Application
• Fatigability
• Dependent On?

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Physiological Changes to Bone

• Modeling and Remodeling
• Bone Hypertrophy
• Bone Atrophy
• Changes during growth years
• Changes during Adulthood
• Changes during Older Adulthood

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Joint Articulations
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Structural Classification

• Synarthroses
• no distinctive movements but can absorb force
• Amphiarthroses
• slightly moveable
• absorb force by providing give
• Diarthroses
• a joint in which there is a separation or
  articular cavity

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Diarthrodial Characteristics

• Articular Cavity
• Ligamentous Capsule
• Synovial Membrane secreting Synovial Fluid
• Articular Surface is Smooth
• Covered w/ cartilage or fibrocartilage

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Diarthrodial Classification

• Irregular

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Diarthrodial Classification

• Irregular
• Hinge

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Diarthrodial Classification

• Irregular
• Hinge
• Pivot

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Diarthrodial Classification

• Irregular
• Hinge
• Pivot
• Condyloid

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Diarthrodial Classification

• Irregular
• Hinge
• Pivot
• Condyloid
• Ball and Socket

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Joint Stability

• Shape of Bony Structure
• Ligamentous Arrangement
• Muscular Arrangement
• Fascia and Skin
• Atmospheric Pressure

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Factors Affecting Range of Motion

• Shape of Articular Surface
• Restraining Effects of Ligaments
• Controlling Action of Muscles
• Diseases

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Assessing Joint Range of Motion

• Number of degrees
• start position to end of maximum movement
• Measuring
• Goniometer
• Videotape/Motion Analysis
• Electrogoniometer