AmputeesArtificial Limbs: Prosthetic replacements for arms, legs, and parts thereof.Amputation Stumps: The part of a limb or tail following amputation that is proximal to the amputated section.Phantom Limb: Perception of painful and nonpainful phantom sensations that occur following the complete or partial loss of a limb. The majority of individuals with an amputated extremity will experience the impression that the limb is still present, and in many cases, painful. (From Neurol Clin 1998 Nov;16(4):919-36; Brain 1998 Sep;121(Pt 9):1603-30)Amputation: The removal of a limb or other appendage or outgrowth of the body. (Dorland, 28th ed)Amputation, Traumatic: Loss of a limb or other bodily appendage by accidental injury.Prosthesis Fitting: The fitting and adjusting of artificial parts of the body. (From Stedman's, 26th ed)Leg: The inferior part of the lower extremity between the KNEE and the ANKLE.Gait: Manner or style of walking.Prosthesis Design: The plan and delineation of prostheses in general or a specific prosthesis.Disarticulation: Amputation or separation at a joint. (Dorland, 28th ed)Tibia: The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the FIBULA laterally, the TALUS distally, and the FEMUR proximally.Man-Machine Systems: A system in which the functions of the man and the machine are interrelated and necessary for the operation of the system.Callosities: Localized hyperplasia of the horny layer of the epidermis due to pressure or friction. (Dorland, 27th ed)Arm: The superior part of the upper extremity between the SHOULDER and the ELBOW.Leg Injuries: General or unspecified injuries involving the leg.Walking: An activity in which the body advances at a slow to moderate pace by moving the feet in a coordinated fashion. This includes recreational walking, walking for fitness, and competitive race-walking.Hand: The distal part of the arm beyond the wrist in humans and primates, that includes the palm, fingers, and thumb.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Lower Extremity: The region of the lower limb in animals, extending from the gluteal region to the FOOT, and including the BUTTOCKS; HIP; and LEG.Upper Extremity Deformities, Congenital: Congenital structural abnormalities of the UPPER EXTREMITY.