A prosthetic is an artificial body part made to replace one that's missing or not working properly. Someone who's lost a leg might wear a prosthetic leg to help them walk, run, or even compete in sports. A prosthetic arm can help someone pick up objects, write, or play an instrument.

Modern prosthetics are remarkable pieces of engineering. Some prosthetic legs have spring-like feet that store and release energy, helping athletes jump and sprint. Some prosthetic hands use sensors that detect tiny muscle movements, allowing the wearer to control individual fingers just by thinking about moving them. Paralympic athletes use specialized prosthetics designed for their sports, and some can run almost as fast as Olympic sprinters.

Throughout history, people have created prosthetics from wood, metal, and leather. Today's prosthetics might include carbon fiber, computer chips, and advanced materials that make them lighter, stronger, and more responsive than ever before.

The field of designing and building prosthetics is called prosthetics, and specialists who fit them to patients are called prosthetists.