provide ready access to the circulation
in people who are having dialysis. Some
types of fistula close spontaneously but
most need to be treated surgically.
fitSee seizure.
fitnessThe capacity for performing phys-
ical activities without exhaustion. Fitness
depends on strength, flexibility, and en-
durance. Because cardiovascular fitness
is the precondition for all other forms of
fitness, regular aerobic exercise (see aero-
bics), which makes the body’s use of
oxygen more efficient, is the basis of any
fitness programme. Specific activities,
such as weight training or yoga, can help
develop strength and flexibility when
included in a programme (see exercise).
When the body is fit, the maximum work
capacity and endurance are increased. A
fit person has a better chance of avoiding
coronary artery diseaseand preventing
the effects of age and chronic disease.
fitness testingA series of exercises
designed to determine an individual’s
level of fitness, primarily cardiovascular
fitness and muscle performance. Fitness
testing is often carried out before a per-
son starts an exercise programme to
evaluate its safety and suitability or
to monitor progress thereafter.
A physical examination is usually per-
formed, including measurement of body
fat, height, and weight. Blood and urine
tests may be done, including an analysis
of blood cholesterol. The performance of
the heart is measured by taking the pulse
before, during, and after aerobic exercise.
Another test involves measuring a per-
son’s overall performance in a standard
exercise. (See also aerobics; exercise.)
fixationIn psychoanalytic theory, the pro-
cess by which an individual becomes or
remains emotionally attached to real or
imagined objects or events during early
childhood. If the fixations are powerful,
resulting from traumatic events, they
can lead to immature and inappropriate
behaviour. Regression to these events is
regarded by some analysts as the basis
of certain emotional disorders.
Fixation also describes the alignment
and stabilization of fractured bones.
Fixation may be external, as with a plas-
ter cast, or internal, using pins, plates,
or nails introduced surgically.
flail chestA type of chest injury that
usually results from a traffic accident or
from violence. In flail chest, several ad-
jacent ribs are broken in more than one
place, producing a piece of chest wall
that moves in the opposite way to nor-
mal as the victim breathes. The injury
may lead to respiratory failure and shock.
Emergency treatment consists of turn-
ing the person on to the affected side or
supporting the flail segment by firm strap-
ping. In severe cases, artificial ventilation
is needed until the chest wall is stable.
flat-feetA condition, usually affecting
both feet, in which the arch is absent
and the sole rests flat on the ground.
The arches form gradually as supportive
ligaments and muscles in the soles de-
velop and are not usually fully formed
until about age 6. In some people, the
ligaments are lax or the muscles are weak
and the feet remain flat. Less commonly,
the arches do not form because of a
hereditary defect in bone structure. Flat-
feet can be acquired in adult life because
of fallen arches, sometimes as the result
of a rapid increase in weight. Weakening
of the supporting muscles and ligaments
may occur in neurological or muscular
diseases such as poliomyelitis.
In most cases, flat-feet are painless
and require no treatment, although in
some cases the feet may ache on walk-
ing or standing. Arch supports can be
worn in the shoes for comfort.
flatulenceAbdominal discomfort or full-
ness that is relieved by passing wind
through the anus or belching. Flatulence
is a feature of many gastrointestinal
conditions, such as irritable bowel syn-
dromeand gallbladderdisorders.
flatusGas, commonly known as “wind”,
which is passed through the anus. Gas
is formed in the large intestine by the
action of bacteria on carbohydrates and
amino acids in food. Large amounts of
gas may cause abdominal discomfort
(see flatulence), which may be relieved by
the passage of wind or by defaecation.
flatwormAny species of worm that has
a flattened shape. Two types of flatworm
are parasites of humans: cestodes (tape-
worms) and trematodes (flukes, schisto-
somes; see liver fluke; schistosomiasis).
flea bitesSee insect bites.FIT FLEA BITES
F