Prosthesis

Some people lose a body part.

They can use an artificial tool. This tool is called a prosthesis.

It can replace a hand or a leg. It can even be a toe. These tools help people move again. Some tools use batteries to work.

Others use cables to move. These tools help people live their lives.

A prosthesis is an artificial device. It replaces a body part that is missing. A person might lose a part due to injury or disease.

Some people are born without a body part.

These devices help in different ways. They can help a person move. They can also help a person look more natural.

There are many types of prostheses. Some replace arms or hands. Others replace legs or feet.

Some arms use a battery. We call these myoelectric devices. They use tiny electrical signals from muscles to move.

Other arms use cables. These are called body-powered devices. They use a harness to pull the parts.

Leg prostheses are also very different. A trans-tibial prosthesis replaces a leg below the knee. A transfemoral prosthesis replaces a leg above the knee.

Walking with a leg above the knee is hard. It takes much more power to move.

Experts help people use these tools. A prosthetist makes and fits the device. Then, a physical therapist helps the person learn to move again.

A prosthesis is an artificial device used to replace a missing body part. People might need one after an injury or because of a disease. Some people are also born without a certain body part. These devices are very important for helping people live their lives. They can restore how a body part works or just help someone look more natural.

A person who has had a limb removed is called an amputee.

There are many ways these devices work. Some are passive, meaning they do not have moving parts. These can be used for looks or for specific jobs. Other limbs are body-powered. These use a harness and a cable to move.

There are also myoelectric devices. These use a battery to provide energy. They work by sensing tiny electrical currents from a person's muscles. These signals tell the artificial hand how to grip or move.

Making these tools is a very careful job. Experts use computer-aided design, or CAD, to create them. This software uses 2-D and 3-D graphics to help design the device. Clinical prosthetists are the professionals who make and fit the devices. They must make sure the device fits the person perfectly. After that, a physical therapist helps the person learn to use it. They might even use a treadmill to help the person practice walking.

History shows that humans have used prostheses for a very long time. The first confirmed use was between 950 and 710 BC in ancient Egypt.

Scientists found a mummy with an artificial big toe made of wood and leather. This toe actually helped the person walk in sandals. In ancient Iran, researchers found an eye prosthetic made of gold and bitumen paste.

Later, in the 16th century, a man named Götz von Berlichingen had a famous iron hand.

Prostheses come in many different shapes and sizes. Some replace parts of the face, like an ear or a nose. Others replace parts of the torso or even internal organs like the heart.

Leg prostheses are often named by where the limb was removed. A transtibial prosthesis replaces a leg below the knee. A transfemoral prosthesis replaces a leg above the knee. Walking with an above-knee device is hard and uses much more energy. Many modern legs now use carbon fiber and small computers to help.

A prosthesis is an artificial device designed to replace a missing body part. People may require a prosthetic implant due to physical trauma, disease, or a congenital disorder, which is a condition present at birth. These devices serve two primary purposes: restoring normal bodily functions or providing a cosmetic appearance. When a person undergoes an amputation, they are referred to as an amputee. Managing this transition requires an inter-disciplinary team of specialists. This team includes physiatrists, prosthetists, nurses, physical therapists, and occupational therapists.

Modern prostheses are created through precise engineering. Creators may use computer-aided design, or CAD. This software interface uses 2-D and 3-D graphics to help designers analyze and optimize the creation. Clinical prosthetists are the professionals responsible for manufacturing and fitting these devices. For lower limb prostheses, they must also assess the user's gait and prosthetic alignment. Once fitted, a rehabilitation physiotherapist, known in America as a physical therapist, helps the user learn to move. They may use verbal instructions, touch, or tactile cues. Training sometimes occurs on a treadmill to help the user experience the challenges of walking.

Upper-extremity prostheses are categorized by how they are powered. Passive devices are the most basic type. These can be static, meaning they have no moving parts, or adjustable. Passive hands are often used for cosmetic reasons, while passive tools serve specific vocational tasks. Approximately one-third of upper limb amputees worldwide use a passive prosthetic hand. Body-powered devices use a harness and cable attached to the opposite shoulder. Recent research has even explored using a user's breathing to power a prosthetic hand.

A more advanced category is the myoelectric device. These arms include a battery system to provide energy for sensing and actuation. Actuation refers to the movement of the limb, often using motors or pneumatic systems. These devices function by detecting minute electrical currents from contracted muscles. Techniques like Electromyography help capture these signals. The device then converts these signals into specific gripping patterns or postures. This allows the artificial hand to execute movements based on the user's muscle activity.

Lower-extremity prostheses replace limbs at various levels, such as the hip, knee, or ankle. They are often divided into two main subcategories: trans-tibial and trans-femoral. A trans-tibial prosthesis replaces a leg missing below the knee. A transfemoral prosthesis replaces a leg missing above the knee. Walking with a transfemoral prosthesis is significantly more difficult. A transfemoral amputee must use approximately 80% more energy to walk than a person with two natural legs. This difficulty arises from the complex movements required by the knee.

To assist with movement, engineers use many advanced materials and technologies. Modern designs often incorporate carbon fiber reinforced polymers, which are lightweight and strong. Other materials include aluminum, polyethylene, polypropylene, and acrylics. For transfemoral users, newer designs use hydraulics, mechanical linkages, and computer microprocessors. These technologies help provide better control.

Prostheses can also be used for parts of the face, known as craniofacial prostheses. These include extra-oral types like nasal or orbital prostheses, and intra-oral types like dental implants.

The history of prosthetics stretches back to the ancient Near East, around 3000 BCE. The earliest evidence of eye prosthetics comes from ancient Iran, where an eye made of gold-covered bitumen paste was found. In ancient Egypt, researchers discovered a mummy with a prosthetic big toe dating from 950 to 710 BCE. This toe was made of wood and leather. In 2011, engineers found that this ancient device actually allowed the wearer to walk in sandals.

Other historical examples include the iron hand of Götz von Berlichingen in the 16th century.

Prosthetics connect to many different fields of science and medicine. They relate to materials science through the development of lightweight composites. They connect to neurology through myoelectric sensing of electrical muscle signals. Even organ replacement falls under this umbrella, with artificial hearts and kidneys serving as internal prostheses.

This field continues to evolve as technology improves the ability of humans to regain mobility and independence.