Hand Function Lecture Notes

Importance of Entire Upper Extremity

• Shoulder Complex: Positions the hand for tasks
• Elbow: Allows the hand to move closer or farther from the body
• Forearm: Orients the palm for grasping or releasing objects
• Wrist: Final orientation and positioning for manipulation
• Digits: Form according to the task demands
• Coordination of the entire proximities is essential for proper hand function

General Hand Function

• Grasping and Releasing: Using hands to hold and manipulate objects
• Varies by size, shape, and weight of objects
• Involves shoulder, elbow, forearm, wrist, and hand interaction
• Sensory Function: Essential for effective hand function
  • Example: Sensory impairment can hinder object manipulation

Functional Position

• Refers to the wrist and hand position needed for function
• Components:
  • Wrist: Slight extension
  • MCP and PIP: Slight flexion
  • Thumb: Opposition
  • DIP: Slight flexion or extension (can compensate with PIP or MCP motion)

Types of Grips

Power Grip

• Requires more strength
• Types:
  • Cylindrical Grip: Holding a bottle, hammer, wheelbarrow handle
  • Spherical Grip: Holding a ball, doorknob, apple
  • Hook Grip: Holding a suitcase or shopping bag
• Key Muscles for Power Grip:
  • Fourth and fifth digits are crucial
  • MCP joints flex to enhance grip

Precision Grip

• Involves fine motor control
• Types:
  • Palmar Pinch (Pad to Pad): Thumb pad to finger pad, MCP and PIP flexion
  • Tip Pinch (Tip to Tip): Thumb tip to finger tip, forms an 'O'
    • Three Jaw Chuck/Palmar Pinch/Tripod: Uses first three digits
    • Lateral Pinch (Key Pinch): Thumb pad to side of index finger
  • Lumbrical Grip: MCP flexion, PIP and DIP extension, like holding a hamburger

Summary

• Hand function is a combination of motor and sensory functions involving the entire upper extremity
• Understanding different grips helps in assessing and improving hand function