Prosthetics by 9I3NA0



          “Imagine an artificial arm that moves naturally in
          response to your thoughts, that allows you to feel both
          the outside world and your own movements, and that
          is as strong and graceful as an intact, biological limb.”
                                                     What are prostheses?

     • An artificial extension that replaces a missing body part.
     • Usually replace parts lost by injury or missing from birth
       or to supplement defective body parts.
     • An artificial limb is a type of prosthesis

A United States Army soldier plays table football with two prosthetic arms
                                                                             Jon Comer, professional skateboarder with a prosthetic leg.
                             The Numbers

•   Trauma is the second leading cause of
    amputation in the U.S.
•   About 30,000 traumatic amputations occur
    in this country every year.
      – Four of every five traumatic amputation
         victims are male, and most of them are
         between the ages of 15–30.
•   Traumatic amputation most often affects
    limbs and appendages like the arms, ears,
    feet, fingers, hands, legs, and nose.
•   More than 90% of amputations performed in
    the United States are due to circulatory
    complications of diabetes, the most
    common cause of non-traumatic leg and
    foot amputations.
                                       The Numbers
•   In the United States, the most common causes of
    lower-extremity amputation are:                          Leading Causes of Lower-Extremity
•   Disease (70%)                                                    Amputation In U.S.
•   Trauma (22%)
•   Congenital or Birth Defects (4%)
•   Tumors (4%)                                                Congenital or
                                                               Birth Defects
•   Diseases that can cause amputation are varied, but               4%
    the most common ones are vascular disease and                              Tumors
    diabetes. Vascular disease limits the circulation to                         4%
    the extremities. Diabetes, which affects blood sugar,
    can decrease the body's ability to heal itself.
•   Trauma resulting in amputation is most frequently
    related to motor vehicle accidents and industrial

•   Congenital malformation or birth defects can                                        Disease
    result in either the person having no limb or a very                                  70%
    short limb that is treated as an amputation, for which
    a prosthetic device is made.

•   Tumors of the bone, called osteosarcoma, can
    sometimes be treated by amputation of the limb.
•       EGYPTIAN TIMES: mummies found
        with prosthetic limbs made of fiber
•       THE DARK AGES: basic peg legs and
        hand hooks
          –    Prostheses were more cosmetic than
               functional; meant to hide disgrace and
               weakness of defeat from other battles.
•       RENAISSANCE: Ambroise Pare
        (contributed to amp. Surgery and
          –    invented "Le Petit Lorrain" (a hand
               operated by springs and catches)
•       Armorers in the 15th and 16th centuries
        made artificial limbs out of iron for soldiers
        who lost limbs. Over the next several
        centuries, craftsmen began to develop
        artificial limbs from wood instead of metal
        because of the lighter weight of the material.

History continued…

 •   1600's - 1800's: refinements of the prosthetic and
     surgical principles; invention of the tourniquet,
     anesthesia, analeptics, blood clotting styptics,
     and disease fighting drugs
 •   Late 19th century: artificial limbs became more
     widespread due to the large number of amputees
     from the Civil War.
       – Technology improved primarily for two
          reasons: the availability of government
          funding and the discovery of anesthetics.
 •   After World War II, the Artificial Limb Program
     was started in 1945 by the National Academy of
     Sciences. This program helped improve artificial
     limbs by promoting and coordinating scientific
     research on prosthetic devices.
 •   In 1962 the government guaranteed prostheses
     for veterans who lost them in the war.
•    20th Century: Modern plastics are stronger and
     more lightweight. The most exciting
     development has been the development of
     myoelectric prosthetic limbs (uses
     electrical signals from arm muscles to move
•    RECENTLY: Computers have been used to
     help fit amputees with prosthetic limbs. Eighty-
     five percent of private prosthetic facilities use
     a CAD/CAM to design a model of the patient's
     arm or leg, which can be used to prepare a
     mold from which the new limb can be shaped.
•    A great deal of emphasis has been placed on
     developing artificial limbs that look and move
     more like actual human limbs.
•    Advances in biomechanical understanding,
     the development of new plastics, and the use
     of computer aided design and computer aided
     manufacturing have all contributed in the
     development of more realistic artificial limbs

                                    What are they made of?

•   The typical prosthetic device consists of a custom fitted
    socket, an internal structure (also called a pylon), knee cuffs
    and belts that attach it to the body, prosthetic socks that
    cushion the area of contact, and, in some cases, realistic-
    looking skin.
•   Should be lightweight; hence, much of it is made from plastic.
•   The socket is usually made from polypropylene.
•   Lightweight metals such as titanium and aluminum have
    replaced much of the steel in the pylon.
•   Newest development in prosthesis manufacture has been the
    use of carbon fiber to form a lightweight pylon.
•   The feet are made from urethane foam with a wooden inner
    keel construction. Other materials commonly used are plastics
    such as polyethylene, polypropylene, acrylics, and
•   Prosthetic socks are made from a number of soft yet strong
•   Physical appearance of the prosthetic limb is important to the
    amputee. The majority of endoskeletal prostheses (pylons)
    are covered with a soft polyurethane foam cover that has
    been designed to match the shape of the patient's sound limb.
    This foam cover is then covered with a sock or artificial skin
    that is painted to match the patient's skin color.
                                   How are they made?
Must be prescribed first, and then fitted.
Measuring and casting
•  1 Accuracy and attention to detail; comfortable and useful; Prosthetist evaluates the amputee.
•  2 Prosthetist measures the lengths of body segments and determines location of bones and
   tendons in the remaining part of the limb. A plaster cast of the stump is made.
Making the socket
•  3 A sheet of clear thermoplastic is heated and then vacuum-formed around the positive mold.
   This thermoplastic sheet is now the test socket; it is transparent so that the prosthetist can check
   the fit.
•  4 Ensure that the test socket fits properly. (if it is a leg, then the prosthetist studies the gait);
   explain how the fit feels; comfort comes first.
•  5 The permanent socket is then formed; usually made of polypropylene and is vacuum-formed
   over a mold in the same way as the test socket.
Fabrication of the prosthesis
•  6 Plastic pieces are made in the usual plastic forming methods: vacuum-forming, injecting
   molding—forcing molten plastic into a mold and letting it cool—and extruding, in which the
   plastic is pulled through a shaped die. Pylons that are made of titanium or aluminum can be die-
   cast; in this process, liquid metal is forced into a steel die of the proper shape. The wooden
   pieces can be planed, sawed, and drilled. The various components are put together using
   bolts, adhesives, and laminating.
•  7 The entire limb is assembled by the prosthetist's technician; uses a torque wrench and
   screwdriver to bolt the prosthetic device together. Prosthetist fits the permanent socket to the
   patient, this time with the completed custom-made limb attached. Final adjustments are then

                             Types of Artificial Limbs

•   The type of prosthesis depends on what part of the limb is
•   Transtibial Prosthesis : an artificial limb that replaces a leg
    missing below the knee.
     – Usually able to regain normal movement because of knee
        (allows for easier movement)
•   Transfemoral Prostheses: an artificial limb that replaces a leg
    missing above the knee.
     – very difficult regaining normal movement; must use 80%
        more energy to walk than a person with two whole legs (due
        to the complexities in movement associated with the knee)
•   Transradial Prostheses: an artificial limb that replaces an arm
    missing below the elbow.
     – Cable operated limbs (attaching a harness and cable around
        the opposite shoulder of the damaged arm)
     – Myoelectric arms
•   Transhumeral Prostheses: an artificial limb that replaces an
    arm missing above the elbow.
     – same problems as transfemoral amputees because of
        complexities of the elbow. Makes mimicking the correct
        motion with an artificial limb very difficult.
                                 How do they work?
                                 -Artificial Arms

•If you are an arm amputee, your choices range from a passive
to a more functional prosthesis.
      •Passive arms have no grasping function but have a
      good cosmetic appearance.
      •Functional arms can either be body-powered or electric
      (most often myoelectric). Cable-operated hands and
      hooks are known as "body-powered" prostheses and are
      operated by means of a cable and harness system. By
      using the back and shoulder muscles, the cable is pulled
      which either opens ("voluntary opening") or closes
      ("voluntary closing") the hand.
      •A "myoelectric" prosthesis is operated when the
      electrodes pick up muscle impulses from your residual
      limb. They are translated into electrical signals that are
      sent to the electric hand to open or close it. Power is
      provided by a battery.

  Myoelectric Arm
        Gait Cycle
        -the series of movements of the leg and foot between one touch of the heel
        on the ground and the next time the same heel touches.

            The C-Leg allows the wearer to:
            •seamlessly speed up or slow down
            •take on hills or slopes
            •recover from stumbles
            •go down stairs step-over-step

            The science behind the knee is revolutionary. It anticipates
            what the wearer is doing and accommodates every change,
            in real time... by utilizing microprocessors to control the
            knee's hydraulic function 50 times a second.

                         How do they work?
                         -Feet Depend on preference,others level, some
                               are more flexible than

The Trias+ foot was modeled after
the anatomical function of the
human foot. It was engineered to
ensure effortless, unified function.
The design combines dual spring
elements in the heel and forefoot.
Made of carbon fiber that can
support for patients who weigh up
to 275 pounds.


• Transradial and transtibial prostheses typically
  cost between US $6,000 and $8,000.
• Transfemoral and transhumeral prosthetics cost
  approximately twice much with a range of
  $10,000 to $15,000 and can sometimes reach
  costs of $35,000.
• The cost of an artificial limb does recur because
  artificial limbs are usually replaced every 3-4
  years due to wear and tear on the artificial limb.
  In addition, if the artificial limb has fit issues, the
  limb must be replaced within several months
•   Continue to develop limbs whose function
    is more and more similar to the real thing
•   Direct bone attachment (osseointegration)
     – attaching prosthetic legs to a titanium bolt
         placed directly in the bone
     (+) may avoid skin sores, sweating, and pain
     (+) Amputees have better muscle control of
         the prosthetic.
     (+) Amputees can wear the prosthetic for an
         extended period of time - with the stump
         and socket method this is not possible.
     (+)Transfemoral amputees are more able to
         drive a car.
     (-) cannot have large impacts on the limb,
         such as those experienced during jogging
•   Biohybrid limbs
                                                                Jesse Sullivan demonstrates one of his prosthetic
     – Insert microchips into muscles to pick up                arms by using a paint roller on the side of his
       signals from the brain                                   house in Dayton, Tenn., July 20, 2006. His left arm
                                                                is a bionic device wired directly into his brain.
     – Two-way talk (send and receive)                          Sullivan lost his arms in May 2001, while working
     – Sensitive to touch and heat                              as a utility lineman.


To top