Biomedical Engineering Reference
In-Depth Information
10.1
INTRODUCTION
The ability to interact with the environment is one of the main characteristics of any living
organism. As human beings our interaction surpasses that of any other animals, as we
have developed a pair of extremely dextrous manipulators—our hands. These, coupled
with an ability to reason and to plan, give us the ability to modify our environment to
suit our requirements. Inevitably, without our hands and arms, and to a lesser extent
our legs and feet, this ability is curtailed. History is replete with examples of ingenious
mechanical replacements for lost limbs that are able, to a limited extent, to accommodate
lost capability. However, to date, no prosthesis comes anywhere near to reproducing the
dexterity of the human hand, and though specialist devices are capable of replacing legs
and feet for certain activities (like running fast) none provides an all-around capability to
match the original.
10.1.1 A Brief History of Prosthetics
It is almost certain that had one of our cave-dwelling ancestors survived a crushed or broken
leg, some form of crutch would have been fashioned to aid with locomotion. In more
recent times, more sophisticated prosthetics with both cosmetic and utilitarian functions
have been developed. An early example of a prosthesis unearthed by archeologists recently
is a big toe made of wood and leather attached to the almost 3000-year-old mummified
remains of an Egyptian noblewoman, shown in Figure 10-1.
It is believed that most Egyptian prostheses were produced for a sense of wholeness,
but analysis showed that the big toe shown in Figure 10-1 was functional and would have
aided with the balance and locomotion of the wearer.
In 424 BC, Herodotus wrote of a Persian seer who had been condemned to death but
escaped by amputating his own foot and making a wooden replacement to walk about 50
km to the next town. In Capua, Italy, archeologists unearthed an artificial leg dating from
about 300 BC that was made of bronze and iron, with a wooden core, apparently for a
below-the-knee amputee (Norton 2007).
FIGURE 10-1
Prosthetic toe made
from wood and
leather attached to a
mummy between
950 and 710 BC.
(Courtesy of the
Museum of Egyptian
Antiquities in Cairo.)
