Frostbite

Frostbite is the freezing of tissues. It occurs when body parts, most commonly the fingers, toes, and the tips of ears and the nose, are exposed for long periods to the cold. Frostbite is a direct result of limited blood circulation. The blood is the body's internal heating system; it carries heat to the body tissues. But prolonged exposure to the cold can constrict blood vessels, causing blood circulation within tissues to slow down. When tissues are deprived of the warmth of circulating blood, ice crystals can then form, leading to tissue death and loss of the affected body parts.