Upper Limb Prosthetics: Harness Systems and Amputation Levels

Posted on Oct 22, 2025 in Other university degrees and diplomas

Prosthetic Harness Systems: Control and Function

A **harness system** is a critical component of body-powered prostheses, particularly for upper limb amputees. It enables users to control their prosthetic device through movements of their shoulders, residual limb, or other body parts.

Components of a Harness System

  • ***Harness***: A flexible or rigid framework that fits around the user’s body, typically the shoulders, chest, or residual limb.
  • ***Cables***: Connect the harness to the prosthetic device, transmitting user movements to control prosthetic function.
  • ***Straps and Buckles***: Adjustable straps and buckles secure the harness in place and allow for customization of fit.

Functionality of a Harness System

  • ***Control***: Enables users to control prosthetic movement and function through their own body movements.
  • ***Stability***: Provides stability and support for the prosthetic device.
  • ***Feedback***: Allows users to feel the prosthetic device’s position and movement, enhancing proprioception.

Types of Harness Systems

  • ***Figure-of-8 Harness***: A common design that wraps around the shoulders and chest.
  • ***Bicycle Harness***: A design that distributes forces across the shoulders and chest.
  • ***Self-Suspending Harness***: A design that uses the user’s own body contours to suspend the prosthetic device.

Benefits of a Harness System

  • ***Improved Control***: Enhances user control over prosthetic movement and function.
  • ***Increased Functionality***: Enables users to perform a variety of tasks with their prosthetic device.
  • ***Customization***: Allows for customization of fit and function to meet individual user needs.

Design Considerations for Harness Systems

  • ***Comfort***: The harness should be comfortable and not cause skin irritation or discomfort.
  • ***Fit***: The harness should fit securely and provide adequate support for the prosthetic device.
  • ***Adjustability***: The harness should be adjustable to accommodate changes in user anatomy or prosthetic needs.

A well-designed harness system is essential for optimal prosthetic function and user satisfaction. Prosthetists work closely with users to design and fit harness systems that meet their individual needs and goals.

Below Elbow Prostheses (Transradial Amputation)

A **below elbow prosthesis** is designed for individuals who have had an amputation below the elbow, resulting in a residual limb with a portion of the radius and ulna bones. These prostheses aim to restore functional ability and independence.

Types of Transradial Prostheses

  1. ***Body-Powered Prostheses***: Use cables and harnesses to control prosthetic movement.
  2. ***Myoelectric Prostheses***: Use electromyography (EMG) signals from the user’s muscles to control prosthetic movement.
  3. ***Hybrid Prostheses***: Combine body-powered and myoelectric control.

Components of Below Elbow Prostheses

  1. ***Socket***: A custom-made socket that fits the residual limb.
  2. ***Terminal Device***: A prosthetic hand, hook, or other end-effector that interacts with the environment.
  3. ***Wrist Unit***: A prosthetic wrist that provides flexibility and rotation.

Benefits of Transradial Prostheses

  1. ***Improved Functionality***: Enhances the user’s ability to perform daily activities.
  2. ***Increased Independence***: Enables users to live independently and participate in various activities.
  3. ***Cosmetic Appeal***: Provides a natural appearance, enhancing the user’s self-esteem and confidence.

Selection Considerations for Below Elbow Prosthetics

  1. ***User Needs and Goals***: Consider the individual’s lifestyle, goals, and preferences.
  2. ***Prosthetic Functionality***: Determine the desired level of functionality and control.
  3. ***Comfort and Fit***: Ensure the prosthetic device is comfortable and fits properly.

Rehabilitation and Training

  1. ***Prosthetic Training***: Teaches users how to control and use their prosthetic device.
  2. ***Occupational Therapy***: Assists users in adapting to daily activities and tasks.
  3. ***Physical Therapy***: Helps users maintain range of motion, strength, and mobility.

A well-designed and fitted below elbow prosthesis can significantly improve an individual’s quality of life and functional ability.

Above Elbow Prostheses (Transhumeral Amputation)

An **above elbow prosthesis** is designed for individuals who have had an amputation above the elbow, resulting in a residual limb with a portion of the humerus bone. These prostheses aim to restore functional ability and independence.

Types of Transhumeral Prostheses

  1. ***Body-Powered Prostheses***: Use cables and harnesses to control prosthetic movement.
  2. ***Myoelectric Prostheses***: Use electromyography (EMG) signals from the user’s muscles to control prosthetic movement.
  3. ***Hybrid Prostheses***: Combine body-powered and myoelectric control.

Components of Above Elbow Prostheses

  1. ***Socket***: A custom-made socket that fits the residual limb.
  2. ***Elbow Unit***: A prosthetic elbow that provides flexion and extension.
  3. ***Terminal Device***: A prosthetic hand, hook, or other end-effector that interacts with the environment.
  4. ***Wrist Unit***: A prosthetic wrist that provides flexibility and rotation.

Benefits of Transhumeral Prostheses

  1. ***Improved Functionality***: Enhances the user’s ability to perform daily activities.
  2. ***Increased Independence***: Enables users to live independently and participate in various activities.
  3. ***Cosmetic Appeal***: Provides a natural appearance, enhancing the user’s self-esteem and confidence.

Selection Considerations for Above Elbow Prosthetics

  1. ***User Needs and Goals***: Consider the individual’s lifestyle, goals, and preferences.
  2. ***Prosthetic Functionality***: Determine the desired level of functionality and control.
  3. ***Comfort and Fit***: Ensure the prosthetic device is comfortable and fits properly.

Rehabilitation and Training

  1. ***Prosthetic Training***: Teaches users how to control and use their prosthetic device.
  2. ***Occupational Therapy***: Assists users in adapting to daily activities and tasks.
  3. ***Physical Therapy***: Helps users maintain range of motion, strength, and mobility.

Challenges of Transhumeral Prostheses

  1. ***Control and Stability***: Above elbow prostheses require more complex control and stability systems.
  2. ***Energy Expenditure***: Users may need to expend more energy to control the prosthetic device.
  3. ***Customization***: Above elbow prostheses often require more customization to meet individual user needs.

A well-designed and fitted above elbow prosthesis can significantly improve an individual’s quality of life and functional ability.

Shoulder Disarticulation Prostheses

**Shoulder disarticulation prostheses** are designed for individuals who have undergone an amputation where the entire arm is removed at the shoulder joint. These prostheses aim to restore functional ability and independence.

Key Features of Shoulder Disarticulation Prostheses

  1. ***Complex Control Systems***: Require sophisticated control systems to manage multiple joints and movements.
  2. ***Customization***: Often requires significant customization to meet individual user needs and preferences.
  3. ***Advanced Materials***: May utilize advanced materials, such as carbon fiber or titanium, for durability and lightweight construction.

Types of Shoulder Disarticulation Prostheses

  1. ***Body-Powered Prostheses***: Use cables and harnesses to control prosthetic movement.
  2. ***Myoelectric Prostheses***: Use electromyography (EMG) signals from the user’s muscles to control prosthetic movement.
  3. ***Hybrid Prostheses***: Combine body-powered and myoelectric control.

Components

  1. ***Socket***: A custom-made socket that fits the residual limb.
  2. ***Shoulder Unit***: A prosthetic shoulder that provides movement and stability.
  3. ***Elbow Unit***: A prosthetic elbow that provides flexion and extension.
  4. ***Terminal Device***: A prosthetic hand, hook, or other end-effector that interacts with the environment.

Benefits

  1. ***Improved Functionality***: Enhances the user’s ability to perform daily activities.
  2. ***Increased Independence***: Enables users to live independently and participate in various activities.
  3. ***Cosmetic Appeal***: Provides a natural appearance, enhancing the user’s self-esteem and confidence.

Challenges

  1. ***Control and Stability***: Requires complex control and stability systems.
  2. ***Energy Expenditure***: Users may need to expend more energy to control the prosthetic device.
  3. ***Integration Complexity***: Often requires integration with other assistive technologies, such as body-powered or myoelectric controls.

A well-designed and fitted shoulder disarticulation prosthesis can significantly improve an individual’s quality of life and functional ability.

Wrist Disarticulation Prostheses

**Wrist disarticulation prostheses** are designed for individuals who have undergone an amputation where the hand is removed at the wrist joint. These prostheses aim to restore functional ability and independence.

Key Features

  1. ***Preservation of Forearm Length***: These prostheses often preserve the length of the forearm, allowing for more precise control and movement.
  2. ***Customization***: Prostheses are customized to fit the individual’s residual limb and meet their specific needs and preferences.
  3. ***Advanced Materials***: May utilize advanced materials, such as carbon fiber or titanium, for durability and lightweight construction.

Types of Wrist Disarticulation Prostheses

  1. ***Body-Powered Prostheses***: Use cables and harnesses to control prosthetic movement.
  2. ***Myoelectric Prostheses***: Use electromyography (EMG) signals from the user’s muscles to control prosthetic movement.
  3. ***Hybrid Prostheses***: Combine body-powered and myoelectric control.

Components

  1. ***Socket***: A custom-made socket that fits the residual limb.
  2. ***Terminal Device***: A prosthetic hand, hook, or other end-effector that interacts with the environment.

Benefits

  1. ***Improved Functionality***: Enhances the user’s ability to perform daily activities.
  2. ***Increased Independence***: Enables users to live independently and participate in various activities.
  3. ***Cosmetic Appeal***: Provides a natural appearance, enhancing the user’s self-esteem and confidence.

Challenges

  1. ***Control and Stability***: Requires precise control and stability systems.
  2. ***Customization***: Often requires customization to meet individual user needs and preferences.

Rehabilitation and Training

  1. ***Prosthetic Training***: Teaches users how to control and use their prosthetic device.
  2. ***Occupational Therapy***: Assists users in adapting to daily activities and tasks.
  3. ***Physical Therapy***: Helps users maintain range of motion, strength, and mobility.

A well-designed and fitted wrist disarticulation prosthesis can significantly improve an individual’s quality of life and functional ability.