Convex and Concave Movement Patterns Lecture

Jun 15, 2024

Lecture on Convex and Concave Movement Patterns

Key Concepts

  • Convex-Concave Rule: Describes the relationship between the surfaces and movements of bones in a joint
    • Convex Surface: The rounded part (e.g., fist with right hand)
    • Concave Surface: The hollowed part (e.g., left hand covering right hand)

Movements Demonstrations

  1. Convex Moving on Concave:

    • When a convex bone moves, its surface moves in the opposite direction to the intended bone movement
    • Example: Raising the arm (clavicle and sternum joint)
      • Clavicle head (convex) moves down as the person raises the arm
  2. Concave Moving on Convex:

    • When a concave bone moves, its surface moves in the same direction as the intended bone movement
    • Example: Knee movement (femur and tibia joint)
      • Tibia (concave) moves in the same direction as the person flexes or extends the knee
  3. Saddle Joint (Thumb CMC Joint):

    • Has both concave and convex surfaces
    • Allows for complex movements combining both principles

Kinematic Chains

  • Open Chain Movement:

    • Distal segment moves while proximal segment is fixed
    • Used to enhance specific muscle strength and range of motion
    • Example: Raising legs
  • Closed Chain Movement:

    • Distal segment is fixed while proximal segments move
    • Requires coordination among multiple joints and co-contraction
    • Example: Standing up, sitting down

Important Concepts

  • Joint Congruency: How well joint surfaces match
    • Close-Packed Position:
      • Joint surfaces are tight and ligaments are stretched
      • Prone to injury but used post-injury for proper healing and preserving ligament length
    • Open-Packed Position:
      • Joint surfaces are loose and ligaments are relaxed
      • More comfortable but can lead to shortened ligaments if used excessively

Clinical Applications

  • Joint Mobilization Techniques:
    • Use knowledge of osteokinematics and arthrokinematics
    • Techniques: Compression, Traction, Shear force, Bending force, Torsion force
    • Applications aimed at realigning joints or enhancing range of motion through manual interventions

Summary

  • Successful rehabilitation and training depend on understanding and correctly applying the principles of convex-concave movements and kinematic chains. Clinicians use varied techniques to ensure proper joint mechanics and facilitate recovery.