Lecture on Hand Anatomy and Function

Introduction

• Hand complexity
  • Essential for movement and various activities
  • Facilitates interaction with the environment and valuable occupations

Functional Components of the Hand

1. Thumb
   • Primary function: opposition
   • Involved in precision grip when paired with the index and middle fingers (e.g., pinch, pick up, manipulate objects)
2. Index and Middle Fingers
   • Function: Precision grip
3. Ring and Little Fingers
   • Function: Power grip

Surface Anatomy of the Hand

• Creases as Landmarks
  • Indicate joints; important in hand therapy and splint making
  • Thumb creases
    • IP joint
    • MCP joint
    • CMC joint movement
  • Palmar Creases
    • Distal palmar crease
    • Proximal palmar crease
  • Finger Creases
    • MCP joint (connected by lines through proximal and distal palmar creases)
    • PIP crease
    • DIP crease
  • Wrist Creases
    • Indicate different rows of wrist movement
    • Include distal, proximal, and sometimes middle wrist creases

Bones and Arches of the Hand

• Three Primary Arches

  1. Longitudinal Arch
     • From wrist joint, through carpal bones, metacarpal bones, and phalanges
  2. Proximal Transverse Arch
     • Formed by carpal bones
  3. Distal Transverse Arch
     • Formed by mid-carpal bones

• Observations of the Arches

  • When making a fist or a power grip, the knuckles form the shapes reflecting these arches
  • Preserving these arches is crucial for maintaining good hand function
  • Changes in the distal transverse arch can affect power grip ability

Additional Arch: Oblique Arch

• Oblique Arch (Oli)
  • Formed by the thumb and the four digits
  • Resembles the shape when holding something like an ice cream cone
  • Important when the thumb is involved in tasks
  • Ensures thumb opposition to each of the four fingers

Conclusion

• Recognizing and preserving the functional components and arches of the hand is crucial for effective hand function and therapy.
• Understanding surface anatomy helps in practical applications like splinting.