artificial limb


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Related to artificial limb: prosthesis

artificial limb,

mechanical replacement for a missing limb. An artificial limb, called a prosthesis, must be light and flexible to permit easy movement, but must also be sufficiently sturdy to support the weight of the body or to manipulate objects. The materials used in artificial limbs include willow wood, laminated fibers and plastics, various metallic alloys, and carbon-fiber composites. One model of artificial leg is made of layers of stockinette cloth coated with plastic; it has duraluminum joints at the knee and ankle, rubber soles on the feet, and a leather cuff cushioning the stump. The cuff fits around the thigh like a corset, holding the artificial leg firmly in place, and connects to a leather belt around the waist. Often, spring joints are employed on foot pieces to give natural-looking movements. Microprocessors and an array of sensors are used to operate the mechanical and hydraulic system of some artifical legs, providing more natural locomotion. Sensors, microprocessors, and nerve stimulators can also be used to transmit stimulatory signals to nerve endings in the stump, allowing the amputee to feel more lifelike sensations from the artificial foot. Other artificial legs sacrifice a natural appearance to achieve greater mobility, such as the C-shaped carbon-fiber Flex-Foot used by amputees to participate in track-and-field sports. Artificial legs may also be secured by suction between socket and stump.

Artificial arms, not having to support the weight of the body, may be made of lighter metals and plastics. They are usually strapped to the trunk and controlled by a shoulder harness. Bionic arms have been developed that permit a person to use thought to control the limited movements of the motorized prosthesis. The commands are transmitted through chest muscle that has been surgically connected to the remaining nerves associated with the lost limb; electrodes linked to the artificial arm convert the sensed electrical signals of the muscle into arm movement. Tests with monkeys have shown that robotic arms can be controlled by the brain's electrical signals directly, using probes implanted in the brain and computer software to interpret the signals, and in laboratory experiments a person has similarly controlled a robotic arm.

Artificial hands vary in structure and utility; research and development has resulted in devices that are both cosmetic and functional. For example, an artificial hand has been devised that utilizes a split hook resembling a lobster claw; this is enclosed within a flexible plastic glove that can be made remarkably lifelike, even having fingerprints. The biceps muscle can be attached to the prosthesis by a surgical procedure called cineplasty, which permits grasping in the terminal device while dispensing with shoulder harnesses. A more recent artificial hand has separate motors for each finger, allowing for a more natural and useful grip and movement; the prosthesis is controlled by electrical signals generated by the arm muscles that normally control the hand. Software and electronics have improved sufficiently that some artificial hands can supply feedback to sensory nerves, enabling the user to feel the size, shape, and rigidity or flexibility of the object being handled.

References in periodicals archive ?
03 ( ANI ): With the backdrop of World War II, an Artificial Limb Center (ALC) has been functioning in Maharashtra's Pune city since the year 1944, with an aim to provide best possible solutions and comprehensive rehabilitation to the amputee soldiers.
She was immediately transferred to Forward Kahuta and was re-operated on November 12, 2017, for preparation for artificial limb grafting.
The Artificial Limb and Appliance Service at Wrexham looks after more than 800 prosthetics wearers across the region.
Sa'ad Hashim slowly makes his way down one of the corridors at the Artificial Limbs and Physiotherapy Center in Sana'a.
Unfortunately, however, the artificial limb has had more disabling consequences for Welsh people through the ways in which it has marked individuals as impaired and dislocated them from the wider community through the influence of prejudice, bigotry and dominant ideas of physical capacity and economic productivity.
Thanks to modern technology the artificial limbs are very well designed, he said.
The camp served beneficiaries from across Sri Lanka with one of the world's best and cheapest artificial limbs, the famous "Jaipur Foot".
It signed a $550,000 (BD207,900) deal with Islamic Relief Worldwide to manufacture artificial limbs for more than 1,000 handicapped Palestinians, including children.
Queen Mary's Hospital at Roehampton, south-west London, was set up especially to create and fit artificial limbs.
Little Nadine Conway suffers from cerebral palsy and had waited months for the manual chair from Wrexham Artificial Limb & Appliance Service.
Maybe Mark Price thinks core Waitrose customers want to pick up a spare hip or an extra set of dentures alongside their free-range quail eggs, safe in the knowledge that any artificial limb will have been responsibly sourced, preferably locally.

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