Causes
Circulatory disorders
Diabetic vasculopathy
Sepsis with peripheral necrosis
Peripheral artery disease which can lead to gangrene
A severe deep vein thrombosis (phlegmasia cerulea dolens) can cause compartment syndrome and gangrene

Neoplasm
Cancerous bone or soft tissue tumors (e.g. osteosarcoma, chondrosarcoma, fibrosarcoma, epithelioid sarcoma, Ewings sarcoma, synovial sarcoma, sacrococcygeal teratoma, liposarcoma), melanoma

Trauma
Severe limb injuries in which the limb cannot be saved or efforts to save the limb fail. Traumatic amputation (an unexpected amputation that occurs at the scene of an accident, where the limb is partially or entirely severed as a direct result of the accident, for example, a finger that is severed from the blade of a table saw)
Amputation in utero (Amniotic band)

Congenital anomalies
Deformities of digits and/or limbs (e.g., proximal femoral focal deficiency, Fibular hemimelia)
Extra digits and/or limbs (e.g., polydactyly)

Infection
Bone infection (osteomyelitis) and/or diabetic foot infections
Gangrene
Trench foot
Necrosis
Meningococcal meningitis
Streptococcus
Vibrio vulnificus
Necrotizing fasciitis
Gas gangrene
Legionella
Influenza A Virus
Animal bites
Sepsis
Bubonic plague

Frostbite
Frostbite is a cold-related injury occurring when an area (typically a limb or other extremity) is exposed to extreme low temperatures, causing the freezing of the skin or other tissues. Its pathophysiology involves the formation of ice crystals upon freezing and blood clots upon thawing, leading to cell damage and cell death. Treatment of severe frostbite may require surgical amputation of the affected tissue or limb; if there is deep injury autoamputation may occur. Athletic performance
Sometimes professional athletes may choose to have a non-essential digit amputated to relieve chronic pain and impaired performance. Australian Rules footballer Daniel Chick elected to have his left ring finger amputated as chronic pain and injury was limiting his performance.
The boot checks the heart rhythm and compresses the limb between heartbeats; the compression helps cure the wounds in the walls of veins and arteries, and helps to push the blood back to the heart.For victims of trauma, advances in microsurgery in the 1970s have made replantations of severed body parts possible. The establishment of laws, rules, and guidelines, and employment of modern equipment help protect people from traumatic amputations. Prognosis
The individual may experience psychological trauma and emotional discomfort. The stump will remain an area of reduced mechanical stability. Limb loss can present significant or even drastic practical limitations.A large proportion of amputees (50–80%) experience the phenomenon of phantom limbs; they feel body parts that are no longer there. These limbs can itch, ache, burn, feel tense, dry or wet, locked in or trapped or they can feel as if they are moving. Some scientists believe it has to do with a kind of neural map that the brain has of the body, which sends information to the rest of the brain about limbs regardless of their existence. Phantom sensations and phantom pain may also occur after the removal of body parts other than the limbs, e.g. after amputation of the breast, extraction of a tooth (phantom tooth pain) or removal of an eye (phantom eye syndrome). A similar phenomenon is unexplained sensation in a body part unrelated to the amputated limb.