People can lose all or part of an arm or leg for a number of reasons. Common ones include

• Circulation problems from atherosclerosis or diabetes. They may cause you to need an amputation.
• Traumatic injuries, including from traffic accidents and military combat
• Cancer
• Birth defects

If you are missing an arm or leg, an artificial limb can sometimes replace it. The device, which is called a prosthesis, can help you to perform daily activities such as walking, eating, or dressing. Some artificial limbs let you function nearly as well as before.