Convex and Concave Movement Patterns

Introduction

• Concepts: Convex and Concave movement patterns
  • Combination of osteokinematics and arthrokinematics

Demonstration (Hand Example)

• Right fist represents convex surface
• Left hand covering right fist represents concave surface

Convex Moving on Concave

• Example: Raising the arm
  • Clavicle movement
  • Joint surface moves in opposite direction to the bone

Concave Moving on Convex

• Example: Knee movement
  • Tibia moves in the same direction as knee flexion/extension

Thumb CMC Joint

• Saddle joint: one surface convex, one surface concave
  • Allows both convex-on-concave and concave-on-convex movements

Kinematic Chains

• Open Chain Movement
  • Distal segment moves, proximal segment fixed
  • Example: Leg raises
• Closed Chain Movement
  • Distal segment fixed, proximal segments move
  • Example: Standing up

Applications in Training and Rehab

• Open Chain
  • Enhances muscle strength and range of motion for specific muscles
• Closed Chain
  • Requires coordination and multiple joint engagement

Distinctions Between Movements

• Open Chain: One primary joint axis
• Closed Chain: Multiple joint axes
• Joint segments:
  • Open Chain: One stationary, one mobile
  • Closed Chain: Both moving

Muscle Usage

• Open Chain: Specific muscle group
• Closed Chain: Multiple muscles, co-contractions

Joint Congruence

• Close Pack Position

  • Joint surfaces match well, high tension in ligaments
  • Example: Knee flexion tightens ligaments
  • Post-injury immobilization often in close pack to preserve ligament length

• Open Pack Position

  • Joint surfaces do not match perfectly, looser ligaments
  • More comfortable, but risk of ligament shortening if used post-injury

Clinical Techniques

• Joint mobilization for abnormal motion or damage
  • Compression force: toward each other
  • Tensile traction: separate joint spaces
  • Shear force: realign joint surfaces
  • Bending force: one side moves, other side stretches
  • Torsion force: apply rotation (occasional)
• Example: Hip manipulation via knee and ankle rotation