Introduction to prosthetic limbs One clear example of the great technological development in terms of improvement of people’s everyday lifestyle is the creation and betterment of prosthetic limbs. Over the recent years there have been constant advancements in artificial limbs, such as the usage of new plastics and materials during the process of creation, the invention of better sockets and interfaces, which allow the patients to get used to the prosthesis more quickly, the development of more realistic designs, which provide the user with the opportunity to feel more comfortable exposing their artificial limbs, and many others.
Nevertheless, this technology cannot be described as a recent invention at all. Prosthesis actually date back from ancient Greek and Roman times, but crucial changes regarding them have not been made throughout the times before the modern era. However, there is a lot of evidence of them being used in the past periods of human history, and though they were mostly made of wood and iron, held to the body with leather attachments, artificial limbs have always been needed in people’s lives. History The pioneers in the development and creation of prosthetic technology were the early Egyptians.
Their artificial limbs were made of fiber and were basic and very limited in terms of function. That is because they were mainly used for a sense of wholeness, rather than functionality. Nevertheless, what is believed to be world’s earliest functioning prosthetic body part is an artificial toe found on the foot of an Egyptian mummy in its burial chamber. The prosthesis is made of wood and leather and belonged to a woman at the age of between 50 and 60 years. The toe is believed to have been functional, since it was joined in three places and the amputation site was well healed.
Another early evidence of the usage of prosthetic limbs is an artificial leg dating to about 300 B. C.. It was made of bronze, iron, and wood, apparently for a below-knee amputee. In 424 B. C. , Herodotus wrote of a Persian seer who was condemned to death but escaped by amputating his own foot and making a wooden filler to walk 30 miles to the next town. There are also several written documents, dating back from ancient Greek and Roman times, which tell about amputees with artificial limbs made mainly by iron and wood.
During the Dark Ages the hand hook and the peg leg were invented and were affordable only to the rich. However, other than that, there was no advancement in the area, since prosthesis were mainly used for hiding deformities and had no functional purposes. In contrast, The Renaissance brought back the interest in the development of sciences, arts and philosophy and provided people with new perspectives of life, thus enhancing progress and evolution in many areas.
It proved to be a rebirth in the history of prosthetics – prostheses during this period were generally made of iron, steel, copper and wood. In the Modern Times the U. S. Civil War and World War II play a big role in the development of artificial limbs, since they were highly needed due to the big number of the wounded. An agreement between The U. S. government and the military companies to improve prosthetic function rather than that of weapons laid the foundations of modern day prosthetic development, which is much more complicated and continues to improve.
What they are, how they work and latest developments Today there is a rapid development in the sphere – one can actually learn to sense their artificial limb and in that way control its movement. While in the past artificial limbs merely resembled the body part they were supposed to replace, now, with the help of artificial intelligence and computer aided design, they are not only more similar-looking to an actual limb, but also functional to an extend that even extraordinary activities and sports, such as cycling for example, could still be enjoyed by the user.
There are four main types of artificial limbs: transradial prosthesis – replacing a missing limb below the elbow, transhumeral prosthesis – replacing a limb above the elbow, transtibial prosthesis – replacing a limb below the knee and transfemorath prosthesis – replacing a limb above the knee. While nowadays there is a variety of types of prosthetic limbs, there are several main components, which remain the same. The socket of a prosthetic limb interferes with the patient’s residual limb.
Therefore it should fit the limb carefully in order to prevent any damage to the skin. The suspension system keeps the artificial limb attached to the body and the most common method relies on suction technology – the prosthetic limb fits snugly onto the residual limb, and an airtight seal keeps it in place. The pylon is an artificial limb’s external frame, which is nowadays made mostly of carbon-fiber composites. One of the latest improvements in the sphere of transradial prosthetics are myoelectric prosthetics.
An arm prosthesis’ main purpose is to functionally replace a limb and resemble its appearance. By combining both these aspects, the myoelectric prostheses are both able to mimic human motion and anatomy and preserve a natural look, without sacrificing one for the other. Due to the great technological advancement in the area, the latest artificial limbs possess various new qualities. The latest improvements include elbows that bend and extend with muscle signals, rotating wrists and thumbs that can change their orientation to different hand positions.
A myoelectric-controlled rosthesis is an externally powered artificial limb that you control with the electrical signals generated naturally by your own muscles. It uses a battery and electric motors to function and it attaches to the remaining part of the limb using suction via a custom fabricated socket. The sensors fabricated into the prosthetic socket detect muscle and nerve activity and then translate it into information that the electric motors use to move one’s joints. If muscle signals cannot be used to control the prosthesis, one may be able to use switches with a rocker or pull-push or touch pad.
The result is that the artificial limb feels like a real one and has the ability to perform a wide range of operations. One can control the strength and speed of the limb’s movements and grip by varying the muscle intensity. If the nerves or muscles in the residual limb are damaged, muscles in the chest or back can be used. What is more, there are sensors and motorized controls that can even allow the user to use their artificial fingers for manipulating small items such as keys and credit cards.
Another type of upper-limb prostheses are the body-powered ones. They use cables to connect the prosthesis to the residual limb in a way that one is able to control the prosthesis with the movement of their own body. These artificial limbs possess several advantages, as its cost is usually lower and they are lighter than externally-powered prosthetics, as they do not have batteries and motors inside, but myoelectric prostheses are generally preferred due to their greater functionality, better grip force and more natural appearance.
Nevertheless, the choice between the two types should be individual for every amputee as one should take into consideration their way of living and personal needs. While the main purpose of these prostheses is to functionally replace an upper-limb, the artificial legs have to be created in a way that they are both able to uphold the weight of the body, balance it and successful perform actions such as walking, running, climbing stairs, etc. A recent innovation in the sphere are artificial bionic limbs that can be controlled with one’s mind.
This happens via myoelectric sensors that are implanted in a patient’s residual limb. In a similar way to the myoelectric arm prostheses, when the brain sends signals to the muscles, they are caught by the sensors and transmitted to the artificial limb, which causes it to move almost simultaneously. Another nent in the sphere is now beefing developed – scientists have created an artificial leg that allows the patient to feel lifelike sensations from their foot. That happened by rewiring the nerve endings in the residual limb, so that they are closer to the skin surface.
Then sensors measuring the pressure of heel, toe and foot movement were fitted to the base of the foot and relayed to a micro-controller which relayed them to simulators inside the shaft where it touched the base of the stump. The simulators vibrate, causing the nerve endings to relay signals to the brain. Ethical issues The technological innovations in the field of artificial limbs prove to be greatly beneficial in social aspects, as they are extremely functional. However, there are several ethical issues that arise. First, these products are still very expensive and therefore unaffordable for many people.
Subsequently comes the question, should finance be provided by the state or is it just a personal obligation. What is more, the circumstances under which one lost their limb are also important. For example, if a soldier has lost a body part in a war, should they be provided with an artificial limb? Another issue, from a futuristic point of view, could be the extreme functionality of an artificial limb for example if an artificial leg becomes stronger, more reliable, capable and instinctive than a real one, would people be willing to replace their limbs with prosthetic ones?
