A prosthesis is a device made to replace a missing human body part. They are used by people who are missing body parts due to accidents, health problems (amputees) or being born without them. Originally, prostheses were simply pieces of wood (for example, wooden legs), but now they are made of lighter and stronger materials.
Currently available prostheses can help return mobility to those with transtibial (below the knee), transfemoral (above the knee), transradial (below the elbow), and transhumeral (above the elbow) amputations. There is still much research to be done before artificial limbs can function with the same versatility as a natural limb; as a result many of the currently available prosthetic limbs are tailored to a specific activity or need.