Gangrene
Gangrene is a term that describes dead or dying body tissue(s) that occur because the local blood supply to the tissue is either lost or is inadequate to keep the tissue alive. Gangrene has been recognized as a localized area of tissue death since ancient times. The Greeks used the term gangraina to describe putrefaction (death) of tissue. Although many laypeople associate the term gangrene with a bacterial infection, the medical use of the term includes any cause that compromises the blood supply (for example, peripheral arterial disease or other blood vessel disease) that results in tissue death in the affected part of the body. Consequently, a person can be diagnosed with gangrene but does not have to be "infected."

There are two major types of gangrene, referred to as dry and wet. Many cases of dry gangrene are not infected. All cases of wet gangrene are considered to be infected, almost always by bacteria. The most common sites for both wet and dry gangrene to occur are the digits (fingers and toes) and other extremities (hands, arms, feet, and legs).