Amputation is the removal of a body extremity by trauma or surgery. As a surgical measure, it is used to control pain or a disease process in the affected limb, such as malignancy or gangrene.
Types of amputation include:
Digital amputation of Hallux (great toe)
- partial foot amputation
- ankle disarticulation (Syme)
- below_knee amputation (transtibial)
- knee_bearing amputation
- above knee amputation (transfemoral)
- hip disarticulation
- amputation of digits
- metacarpal amputation
- wrist disarticulation
- forearm amputation (transradial)
- elbow disarticulation
- above-elbow amputation (transhumeral)
- shoulder disarticulation and forequarter amputation
Hemicorporectomy is the most radical amputation. Genital modification and mutilation often involves amputating tissue, although it is usually not a result of injury or disease.
As a rule, partial amputations are preferred to preserve joint function, but in oncological surgery, disarticulation is favored.
Curved knives such as this one were used, in the past, for some kinds of amputations.
The first step is ligating the supplying artery and vein, to prevent hemorrhage. The muscles are transsected, and finally the bone is sawed through with an oscillating saw. Skin and muscle flaps are then transposed over the stump, occasionally with the insertion of elements to attach a prosthesis.
Some amputees experience the phenomenon of phantom limbs; they feel body parts that are no longer there. These limbs can itch, ache, and 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.
In many cases, the phantom limb aids in adaptation to a prosthesis, as it permits the person to experience proprioception of the prosthetic limb.
In some rare cases when a person has become trapped (on account of getting a limb stuck) in a deserted place, with no means of communication or hope of rescue, the victim has amputated his own limb:
- In 2003, 27-year old Aron Ralston amputated his forearm using his pocketknife and breaking and tearing the two bones, after the arm got stuck under a boulder when hiking in Utah.
- A month later, an Australian coal miner amputated his own arm with a Stanley knife after it became trapped when the front_end loader he was driving overturned three kilometers underground.  (http://www.smh.com.au/articles/2003/06/29/1056825279321.html)