Joints

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Joints
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Major Joint Classifications

• Synarthrodial
• Amphiarthrodial
• Cartilage
• Ligament
• Diarthrodial

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Diarthrodial Joints

• Characteristics
• Joint Capsule

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Diarthrodial Joint Types

• Gliding
• Hinge
• Pivot
• Condyloid
• Saddle
• Ball and Socket

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Range of Motion of Joint Type

• Anatomical Compromises
• some sacrifice mobility for stability
• some sacrifice stability for mobility
• Flexibility

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Planes of Movement

• Three primary planes
• Sagittal
• Frontal
• Transverse

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So How Can Knowledgeof Planes Help Us?

• More effectively determine cause(s) of (sport)
  injury
• More effectively correct poor movement practices
• More effectively...

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Axis of Rotation

• The line formed by the intersection of the two
  planes NOT involved in the movement.
• Perpendicular to Plane of Movement.

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Levers

• Machines
• composed of a rigid bar and a fulcrum.
• eg. of rigid bar?
• eg. of fulcrum?

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Levers

• 3 Classifications
• 1st Class -
• 2nd Class -
• 3rd Class -

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Articular (Hyaline) Cartilage

• Location Covers articulating ends of bones (in
  synovial joints)
• Purposes
• decrease friction
• decrease load

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Characteristics of AC

• Highly Specialized
• Can withstand relatively rigorous joint
  environment without failure.
• Isolated tissue
• Assists fitting of bone ends

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Importance of AC

• Least understood tissue in the body
• Known Information
• Limited capacity for self-repair
• does not follow Wolffs Law (as we know it)

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Factors affecting Breakdown of AC

• High load
• total number of stress peaks
• changes in the intrinsic molecular and
  microscopic structure of AC
• changes in its mechanical properties

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How does Breakdownof AC occur?

• loosens the collagen matrix
• decrease in stiffness
• increase in permeability

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Special Cases

• Disruption of Load carrying capacity of AC
• Knee Meniscectomy
• Ligament Rupture
• Abnormal Joint Articulation
• Cartilage degeneration
• Excessive loads and load distribution disruptions

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Joint Degeneration

• Sport Examples