Treas. Reg. '1.213-1(e)(1)(ii)
What are artificial limbs?
Artificial limbs, also known as prosthetics, are fake limbs that replace appendages that have been lost to amputation, severe injuries, or other maladies. They are meant to improve an individual's appearance, range of motion, and ability to perform everyday tasks. These limbs can be made for nearly any part of the human body, and can be designed for cosmetic, functional or both potential uses.
The earliest known prosthesis dates back to 950 B.C. in Ancient Egypt, which was discovered in Cairo in 2007 by an archaeological team from Manchester University. The artificial big toe was found on the foot of a mummy of an Egyptian noblewoman and was made of wood and bound together by leather thread. The "Cairo Toe," as it is known, showcases both cosmetic and prosthetic qualities, and its unique design is the earliest example we have of biological mimicry that is emulated in artificial limb construction to this day (BBC).
How are artificial limbs created?
Individuals who are looking to purchase an artificial limb should seek out the skills of a prosthetist, a person who has extensive experience creating and fitting prosthetics. Typically, these professionals require a variety of skills, including engineering, anatomy and physiology to ensure that artificial limbs fit properly and provide the optimal degree of support and utility for the wearer.
The process to create an artificial limb is quite extensive and is contingent on a number of outside factors. First, if an amputation surgery is planned, a prosthetist may be able to take measurements of the limb before surgery to create an accurate replica, but typically he/she will opt to make a plaster mold of the residual limb to begin the process. This mold allows the prosthetist to coordinate its construction based on the condition of the muscles, tendons and bones after the patient has been able to recover from the surgery and the swelling has subsided.
After the device has been created and fitted, physical therapy is a major step in helping patients return to normalcy, as they will have to learn how to perform important everyday activities while wearing their prosthetics. In the cases of leg amputations, this is an especially difficult undertaking to re-learn how to walk and develop a gait that does not place undue strain on other parts of the body. Lastly, prosthetists must examine during the physical therapy process whether the patient's prosthetic has any interference with underlying tissue, which may need to be resized or replaced over time. These visits will typically last throughout the patient's life, as most prosthetics only have a lifespan of about three years and new artificial limbs will need to be created to compensate for changes in body shape and device deterioration (Harvard University).