June 13, 2022
February 13, 2024
Eddie Zepeda

How Do Prosthetic Arms Work?

Eddie Zepeda
Eddie Zepeda

A functional prosthetic arm helps those who have undergone an arm amputation live a full and happy life. They are designed to mimic the functionality and appearance of a real arm. If you’ve recently had an arm amputation or will have one soon and need upper limb prosthetics, we recommend reading this helpful amputee arm guide by the PrimeCare Orthotics & Prosthetics healthcare professionals.

Different Amputation Levels for Upper Extremities

People who have suffered from upper limb loss or limb differences have a wide variety of residual limb levels, ranging from partial finger amputations to shoulder amputations. Some individuals may even have lost more than one limb.

Amputation of the upper extremity is a major surgical procedure. The degree of amputation typically depends on the condition and severity of the injury.

Partial Finger / Partial Thumb Amputations

This type of amputation is usually the result of a traumatic incident, such as a severe laceration, crushing injury, thermal burn, or due to cancer or a vascular anomaly. The surgeon will remove only as much of the finger or thumb as is necessary to ensure adequate healing and minimize the risk of infection. Sometimes, the remaining portion of the finger may still help grasp objects and perform daily activities.

— Metacarpal/ Transmetacarpal Amputation

Metacarpal/transmetacarpal amputation is a last resort when other treatments and surgeries have been unsuccessful in alleviating pain and restoring hand function. This surgical procedure removes the metacarpal, the long bones in the hand that connect with the wrist bones, and sometimes also includes the removal of the muscles, nerves, and tendons located around the affected area.

— Wrist Disarticulation

Wrist disarticulation amputation — also referred to as below-elbow amputation — involves the removal of three bones in the forearm: the radius, ulna, and humerus, as well as all the soft tissue and tendons connected to them. However, the muscles, ligaments, and skin above the amputation point usually stay intact. Wearing a device with a prosthetic hand will offer more control over the remaining limb and an increased range of motion.

How Does a Prosthetic Arm Work

— Transradial Amputation

Transradial amputations are among the most common upper limb amputations whereby the hand, wrist, and/or forearm are removed to treat severe injury or vascular problems, often followed by wearing a below-elbow prosthesis. The surgeon carefully removes the affected tissue during the procedure while preserving as much of the surrounding muscles, nerves, and blood vessels as possible.

— Elbow Disarticulation

A surgical procedure that completely removes the humerus bone from the radius and ulna (forearm) bones. As a result of elbow disarticulation, the patient loses most of the movement of the arm, but some elbow motion is still possible. Upper limb prostheses can restore arm and hand function after the procedure.

— Transhumeral Amputation

A transhumeral amputation is the amputation of the arm at or above the elbow joint. This procedure involves the removal of the entire arm, including the humerus bone, and is typically undertaken in cases of severe trauma or due to medical conditions. It is the most common type of upper-limb amputation. The remaining stump is fitted with a transhumeral prosthesis to retain some arm function.

— Shoulder Disarticulation

Also known as an above-shoulder amputation, shoulder disarticulation amputation removes a person's entire upper arm from the shoulder joint. This procedure is usually the most extensive amputation surgery in a person's upper body. It is uncommon and only recommended for limb-threatening illnesses, malignant tumors, infections, or irreparable trauma.

— Forequarter Amputation

Forequarter amputation is an intracapsular thoracic amputation where the entire arm, shoulder, scapula, and clavicle are removed. This form of amputation requires a prosthetic system with several components, such as a socket for the scapula and clavicle, a prosthetic shoulder joint, a prosthetic elbow joint, a socket at the wrist, and a terminal device (hand). A wide range of full-arm prosthetics is available, including passive and body-powered to myoelectric, hybrid, and activity-specific systems.

The Importance of Rehabilitation

After surgery, the amount of inpatient care required to rehabilitate from an amputation varies from person to person. People usually stay one to two weeks in a hospital before beginning outpatient rehabilitation.

Inpatient care provides patients and families access to a team of experts who help answer any questions during this transition. Outpatient rehabilitation is comparable to inpatient care, though individuals usually visit their doctors weekly and complete exercises at home between physical therapy sessions.

Rehabilitation is vital for amputees because it helps them to adjust to a new way of life, regain strength and mobility, and develop independence. Physical therapy helps build muscle, gain strength, and improve the movement of the remaining limbs.

Occupational therapy teaches amputees how to use prosthetic devices, adjust to a new lifestyle, and improve self-care and communication skills. Lastly, psychological therapy provides tools to cope with the emotional and psychological aspects of amputation, such as anxiety, mood fluctuations, and changes in body image.

What Is a Prosthetic Arm?

A prosthetic arm is an artificial limb to replace an arm or hand lost due to injury, disease, or disability. It is made of a combination of components, including artificial joints and motors, to enable the user to control the arm's movements in a way that mimics natural movement.

Some prosthetic arms have sensors and/or electrodes which allow the user to receive feedback from the artificial limb. These devices are capable of highly sophisticated movements and provide sensory feedback to the user. Arm prosthetics are used for activities such as typing, cooking, and even playing sports and musical instruments.

What Are the Components of a Prosthetic Arm?

The components of a prosthesis arm work together to give the patient the necessary functions. These components include:

  • Limb: The limb is made from durable and lightweight materials, so it's comfortable yet sturdy.
  • Socket: The prosthetic arm socket connects the residual limb to the arm prosthetic. This must be a comfortable fit to improve the functionality and wearability of the prosthetic arms. Each prosthetic is made from a personalized mold to fit a patient's residual limb perfectly.
  • Suspension system: This component secures the prosthetic to the limb. Different suspension systems include an elastic sleeve, a suction socket, a harness, or a self-suspending socket.
  • Control system: The activity of moving the arm is impossible with a prosthetic arm as the brain cannot send signals to it through nerve pulses. Control systems used in prosthetics involve body-powered, myoelectric, or motor-controlled mechanisms.

How Do Prosthetic Arms Work?

Several arm prosthesis options are available to meet a patient's specific needs. These range from purely cosmetic to mechanical prosthetics and are classified according to the function they provide. Examples of these include:

— Passive Prosthetics

These prosthetics serve a purely aesthetic purpose, allowing amputees to enjoy their body's restored symmetry and a more natural appearance. Generally comprised of lightweight prosthetic arm materials and simple maintenance, these prostheses replicate arms and hands with remarkable realism. An amputee typically covers the cosmetic prosthetic with a sleeve for optimal effect so that just the aesthetic portion of the device is visible.

— Body-Powered Prosthetics

Body-powered prostheses use a system of cables that connect the artificial limbs to another part of the body, typically the opposite shoulder. By moving this shoulder, the individual can actively manipulate the prosthetic by opening and closing a jaw or pincher feature at the end. In terms of cost, these prosthetics are the most economical option, making them an ideal choice for those seeking a functional prosthetic on a budget.

— Externally Powered (Myoelectric) Prosthetics

Myoelectric-driven prostheses are the most sophisticated and costly type of prosthetic. They are driven by electrical signals produced by the muscles that remain in the limb when flexed or relaxed. These signals are translated by electrodes placed in the body and then forwarded to the prosthesis to move it as desired. This technique formed the foundation for the invention of the bionic arm.

above-the-elbow prosthetic arm

— Hybrid Prosthetics

Hybrid prostheses integrate body-powered and electrically powered components to provide a better functional outcome than single-component prostheses. This is especially beneficial for individuals with high levels of limb loss who need more than one movable prosthetic part.

— Activity-Specific Prosthetics

Activity-specific prostheses help individuals complete work, sports, hobbies, and other activities that their residual limb, passive body-powered or electrically powered prostheses, cannot do. We specialize in constructing devices explicitly tailored to the needs of those individuals, enabling them to participate in activities they otherwise may not have been able to.

How Much Does a Prosthetic Arm Cost?

The specific cost of a prosthetic arm depends on the complexity of your desired system and how much your insurance will cover. Generally, you can expect to pay around $5,000 for a cosmetic prosthetic without insurance.

If you have a functional prosthetic with a hook, you’ll likely pay around $10,000 without insurance. You may spend anywhere from $20,000 to $100,000 for the latest myoelectric arm technology.

At PrimeCare Orthotics & Prosthetics, we provide our patients with many resources to help them decide which prosthetic is right based on cost.

Do You Really Want to Have a Prosthetic Arm?

While there are many different benefits to having a prosthetic arm, you must take the time to understand whether or not you are ready to take on the responsibility and effort it takes to not only get one but to use it and care for it properly.

Additionally, suitable candidates must be in good physical health.

If you’re considering getting a prosthetic arm, consider these questions to help you make your decision:

  • Do you have enough soft tissue to cushion the remaining bone?
  • Are you constantly in a lot of pain? If so, is the pain level unbearable?
  • What is the current condition of the skin on the limb?
  • What is the range of motion that you have for the residual limb?
  • Is the other arm healthy and fully functional?
  • What was your activity level before the amputation?
  • What mobility goals do you want to reach?

Unsure if you're a suitable candidate? Our professionals are always available to discuss your concerns and answer your questions about prosthetic devices.

prosthetic arm socket

Is It a Good Idea to Buy a Ready-Made Prosthetic Arm?

While cutting some corners and purchasing a pre-made prosthetic arm is possible, the outcome isn’t always ideal. One of the most critical steps in using a prosthetic arm successfully is ensuring it fits perfectly onto your body.

How well the prosthetic fits is essential to helping you achieve your mobility goals. Although it will take longer at the beginning of the fitting process, it will pay off in the long run as you’ll have a prosthetic designed for you.

We're Here to Help

Nothing is more important than working individually with our upper limb amputees and getting to know their unique conditions. PrimeCare Orthotics & Prosthetics is always here to answer your questions, provide guidance, and help you live a life you may not think was possible. If you’re ready to take the next steps toward a new prosthetic arm, please get in touch with our team today!


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A grandfather with a prosthesis walks with his grandchildren.