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1. Bionics 4
Kevin Warwick

2. Artificial Limbs
• An artifasdficial limb usually replaces a missing
limb, such as an arm or leg.
• The type of artificial limb used is determindfed
largely by the extent of amputation of the missing
extremity – each one is a little different.
• Reasons include disease, accidents, and congenital
(birth) defects.

3. Geography
• Likely reasons for an amputation depend on location.
• In USA & Europe circulatory disease, cancer and
infection are the leading causes.
• In Africa the most likely causes are industrial,
vehicular, or a war related accidents – again infection
is a problem.

4. This Presentation
• More interested in the legs and arms themselves
• Neuroprosthetics & Enhancements etc are mostly a
separate lecture

5. History
• Two artificial toes have been found on Egyptian
mummies – these date back to 1,000BC. However it is
not known if they were actually used in life.
• The first artificial leg, from archaeology, is the Roman
Capua Leg. This was found in a tomb in Capua, Italy,
and dates back to 300BC. It was made of wood and
copper.
• In the 15th century artificial limbs were often made
out of iron for soldiers and sailors. However wood
came to be used much more, simply because of its
weight.

6. Wooden Legs
• Such a wooden leg could
be simply fixed.
• Or it could be hinged at
the knee to assist walking
• No hinge – possible
strange gait

7. Developments
• In the 19th century, artificial limbs became more
widespread due to the large number of amputees from
wars.
• Helped by the discovery of anesthetics.
• In the 20th century scientific research and commercial
possibilities opened the field further.
• In recent years, a great deal of emphasis has been placed on
developing artificial limbs that look and move more like
actual human limbs.
• General new technology (plastics, CAD, manufacturing,
medicine) have all improved the end results.

8. Types of Prosthetic
• Transtibial Prosthesis replaces a leg missing below the knee. Such amputees can
regain normal movement more readily than those with a transfemoral
amputation - retaining the knee allows for easier movement.
• Transfemoral Prostheses replaces a leg missing above the knee. Such amputees
can have a very difficult time regaining normal movement. A transfemoral
amputee must use approximately 80% more energy to walk than a person with
two whole legs.
• Transradial Prostheses replaces an arm missing below the elbow. Two main
types of prosthetics are available. Cable operated limbs work by attaching a
harness and cable around the opposite shoulder of the damaged arm.
Alternative is myoelectric arms – muscle sensing.
• Transhumeral Prosthesis replaces an arm missing above the elbow. Such
amputees experience some of the same problems as transfemoral amputees,
due to the similar complexities associated with the movement of the elbow.
Mimicking the correct motion with an artificial limb is very difficult.

9. Recent Developments
• New plastics and other materials, such as carbon
fibre, have allowed artificial limbs to be stronger and
lighter, limiting the amount of extra energy necessary
to operate the limb. This is especially important for
transfemoral amputees.
• Other synthetic materials have allowed artificial limbs
to look much more realistic, which is important to
transradial and transhumeral amputees because they
are more likely to have the artificial limb exposed.

10. Artificial Legs
• Is only one leg missing?
• How much of the leg is missing?
• Clearly these issues are vital to
the type of artificial leg needed
• The more to be replaced, so the
more difficult the problem is.

11. C-Leg
• The best known present day artificial
leg is the C-Leg produced by Otto Block.
• The user can choose between two
modes: one for walking and one for
bicycling (or any other preprogrammed
activity). The "problem" is switching
between modes, as the wearer has to
swing the leg forward in a jerky fashion.
• The C-LEG supports up to 10
programmable modes, switchable
through a small remote control device
about the size of a car alarm remote.
Reprogramming a mode with another
special activity requires a technician.

12. C-Leg
• An inbuilt microprocessor
interprets the user’s
movements and anticipates
their actions, allowing motion
changes in real time.
• The system is actuated
through the leg’s hydraulic
movement.
• It gives users greater
flexibility to change speed or
direction without sacrificing
stability.

13. C-Leg
• The 10 switchable modes enable various sports
activities, including cycling, running, natural driving
and other programmable activities that require
different leg actions to normal walking and stair
climbing.
• Current challenges are to stretch the unit’s battery
life to 50 hours on one charge and to make the leg
salt-water resistant. These are both requirements
to support military use.

14. Heather Mills
• In August 1993 Heather was hit by a police
motorcycle by Kensington Palace, London.
• Her injuries included crushed ribs and a
punctured lung. She needed a metal plate put
into her pelvis and also the amputation of her
left leg below the knee.
• Mills has a prosthetic leg, taking it off and
showing it to USA talk show host Larry King
during his interview with her in October 2002.

16. Feet
• With artificial legs usually the knee joint is critical
• Feet tend to be either non-existent, e.g. Aimee
Mullins, or are more for cosmetic purposes – they
are not functional
• Stability is important but not dexterity
• Tend to be purpose directed – what is the leg for?

17. Artificial arms and hands
• Stability and power carrying are not big issues here
• Elbow joints clearly are important
• But most critical are hand movements – what will
the hand have to do? – how is it to be controlled? –
what will it look like?
• Functionality is important – but cosmetics are also
very important

18. Artificial Arms and Hands
• Important if one or both have been lost
• It is possible to do many activities with one hand or
using a residual limb(s).
• Many arm amputees do not use any prostheses or
special tools. It is easy and possible to get
dressed/write/type with one hand.
• Some continue their work with a special attachment
only e.g. carpentry, car driving.
• Nevertheless, having a prosthesis can be a big help,
especially for manual labour.

19. Prosthesis
• Learning to use a prosthesis takes hard work and
practice. It is only worth the effort if it improves a
person’s ability to hold and use things.
• An arm-hand prosthesis has three basic parts: the
socket, which fits over the residual limb; the arm
section, which may or may not include an elbow joint;
and the hand/tool, which can be like a hand, a hook,
or some other shape to allow the person to hold and
use things.
• Often a hook is preferred as it is extremely functional

20. Body-powered prostheses
• Some prosthetics clinics make available body-
powered arm prostheses.
• These have straps or cables that attach to other
parts of the body, so that by moving a shoulder, the
person can make the hand close or bend the elbow
of the prosthesis.
• Body-powered prostheses often have metal hooks
instead of fingers. The hooks are better than
artificial fingers for hard work and can pick up
smaller things.

21. Electric-powered prostheses
• Electrical prostheses are available in some
countries, but they are relatively expensive.
• Perhaps not available where they are needed -
most (countries at war/strife).
• Muscles in the arm operate electric motors, which
close and open the hand.
• Electrical prostheses look more like real arms, but
they are not as strong and they break more easily.

23. Cosmetic prostheses
• Cosmetic arms look like real arms but the hands
either do not move at all or can be pulled (by another
hand) into a fixed position.
• They can help a little (for example, the cosmetic arm
can hold down a paper while the other hand writes
on it), but the real purpose of a cosmetic arm is to
look natural.
• Very useful for someone in the public eye.
• Useful if only one hand has been lost.

24. Krukenberg surgery
• Some people missing both hands choose to have
surgery, called the Krukenberg surgery.
• This separates the two bones of the forearm to make
a new kind of “hand.”
• The bones can be used like two fingers, and because
the skin and bones are real, the person can feel what
they are doing.
• This greatly benefits amputees who are blind.
• It is still possible to wear a prosthesis over the
residual limb even after the surgery.

25. The i-LIMB Hand
• From Touch Bionics
• http://www.touchbionics.com/

26. The i-LIMB Hand
• The i-LIMB Hand is controlled by a system that uses a two-
input myoelectric (muscle signal) to open and close the hand’s
fingers.. This signal is picked up by electrodes that sit on the
surface of the skin. Existing users of basic myoelectric
prosthetic hands are able to adapt to the system and can
master the device’s functionality within minutes.

27. Bionic Arm
• In 2001 Jesse Sullivan lost both his
arms when he was electrocuted.
• He has received an artificial arm/hand
controlled from his nervous system.
• The nerves that used to go to the arm
were moved onto chest muscles. The
nerves grew into the chest muscles, so
when Jesse thinks "close hand," a
portion of his chest muscle contracts
and electrodes that detect this muscle
activity tell the computerized arm to
close the hand. Thus, Jesse thinks
"close hand" and his artificial hand
closes.
• Work of Todd Kuiken.

28. Claudia Mitchell
• Lost her left arm in a
motorcycle accident.
• In 2007 became the 4th
person to have this type
of procedure – Rehab
Institute of Chicago

29. Next Lecture
• Deep Brain Stimulation