A lost arm can make it difficult to perform everyday tasks like eating, dressing, and holding objects. Prosthetic arms help many individuals restore some of their abilities by mimicking the movement of a real arm.

Prosthetic arms are advanced replacements for a missing limb. They can be body-powered, with shoulder or chest movements controlling the cables and cords, or myoelectric, which means they use sensors placed on the skin to detect electrical signals from the user’s muscles. The sensors send these signals to motors in the prosthetic arm that control movements like opening and closing the hand, rotating the wrist, or bending the elbow.

5 Different Types of Prosthetic Arms And How They Work

Some prosthetic arms are made just for appearance, while others can help with movement. How they work depends on the kind of prosthetic and how much control the user needs. Below are the most common types of prosthetic arms and how each one functions.

1. Body-Powered Prosthetic Arms

Body-powered arms use a system of cables, straps, and pulleys connected to the body, usually the shoulder or upper chest. When the user moves their shoulder or arm stump, that motion pulls the cable, which opens or closes a hook, hand, or elbow joint on the prosthetic. These arms operate using body strength and movement, not electricity. They’re strong, reliable, and good for basic tasks like holding, lifting, or pulling.

2. Myoelectric (Battery-Powered) Prosthetic Arms

Myoelectric prosthetics use electrical signals from the muscles in the remaining part of the arm. Sensors on the skin detect tiny muscle movements when the user flexes or relaxes. These signals are sent to a battery-powered motor that controls the prosthetic’s hand, wrist, or elbow. This allows the user to move the arm by thinking about moving their muscles. The result is smoother, more natural movement, like opening and closing the hand or rotating the wrist. These are ideal for tasks that need better precision, but they also require regular charging.

3. Passive Prosthetic Arms

Passive prosthetics don’t move or assist with tasks. They’re mainly for appearance and help give the body a natural, balanced look. These arms are made from lightweight materials and shaped to look like a real arm or hand. A soft outer layer or skin-like cover may be added to match skin tone. Some users wear a cosmetic sleeve over the arm to make it look even more real. These prosthetics are useful in social settings and can assist with light tasks like supporting clothing or pushing objects, but they do not bend or grip independently.

4. Hybrid Prosthetic Arms

Hybrid arms combine both body-powered and myoelectric technology. For example, the elbow might be moved by a shoulder motion (like in a body-powered system), while the hand opens and closes using electrical signals (like a myoelectric system). This setup gives the user more control and is especially helpful for those with above-the-elbow amputations, where multiple joints need to move independently. Hybrid arms offer flexibility and a better range of motion, especially for people with more complex needs.

5. Activity-Specific Prosthetic Arms

These arms are built for one main activity, such as riding a bike, playing a sport, lifting weights, or using tools. They don’t usually copy the look of a hand or arm, but are shaped for specific tasks. Some may be passive (no movement), while others may use body motion or electric signals depending on the activity.

For example, a prosthetic made for rock climbing may include a special grip, while a sports version might have padded hooks or handles. These arms are designed to make it easier to enjoy hobbies or do work that general-use prosthetics can’t support.

5 Main Parts of a Prosthetic Arm and How They Function

The parts of a prosthetic arm move together to make it look and feel like a real arm. Each part does something different. When used together, they let the person move, grip, lift, and do other everyday things.

1. Socket

The socket connects the prosthetic arm to the user’s remaining limb. Prosthetists custom-make it to fit securely and comfortably, often with a soft liner inside. The socket uses suction, a locking pin, or a vacuum seal to keep the prosthetic in place. A secure fit improves control and minimizes unwanted movement or discomfort during daily activities.

2. Arm Frame (Pylon)

The part inside the prosthetic that gives it shape and strength is called the arm frame. It’s like the arm’s “skeleton.” It links the socket to the hand or hook, among other parts. Typically, this frame comprises sturdy yet lightweight materials like plastic or metal. These materials support daily use without adding excessive weight or causing fatigue.

3. Joints

Joints are the parts of prosthetic arms that move. The arm may have joints at the wrist, elbow, or fingers. The elbow joint allows the arm to bend and straighten like a genuine elbow, and the wrist joint allows the hand to move to the left or right. Some very modern prosthetic arms have fingers that can open and close independently. With joints, the prosthetic arm can move and be used more. They let the person reach, lift, or rotate their hand while still letting their arm move normally.

4. Hand or Tool (Terminal Device)

The terminator is the hand or tool at the end of the arm. It is what the person holds on to or uses to carry things. Manufacturers shape some hands like hooks or tools, which may work better for specific jobs. The user can choose based on their wants. For example, a hook might be better for heavy work, and a hand might be better for everyday tasks. This part can be opened and closed to grab objects. It helps with everyday tasks, like holding a cup, getting keys, or bringing a bag.

5. Control System

It’s the control device that moves the prosthetic arm. You can choose between two main types of control systems: myoelectric and body-powered.

  • Body-powered arms rely on cables and straps. These cords pull the arm or hand when the person moves their shoulder or chest.
  • Myoelectric arms are equipped with small sensors in sockets. The muscles send small electric impulses to these arms, which are used to move the fingers, arm, or hand. This method feels more natural, and your body doesn’t have to move as much.

Conclusion

People who have lost their arms can live much better lives with prosthetic arms. They help people do activities again, such as eating, writing, dressing, and many other normal things. Different parts help the prosthetic arm work. Body movement or electrical signals from muscles control these parts.

Experts create all prosthetic arms to move as naturally as possible. This is possible with a cable system that moves with your shoulder or sensors that respond to muscle signals. Together, the hand, frame, joints, and control system make it easier for people to grip, move, hold, and carry things. Regular care is important to keep these components functioning at their best. At Celerity Prosthetics, we offer specialized Prosthetic Upper & Lower Care to ensure your prosthetic arm stays in excellent working condition. Our team will assist you from consultation to fitting and provide ongoing maintenance to help you live life to the fullest.