metals is generally used for back teeth.
If a front tooth is chipped, a bonding
technique (see bonding, dental) may be
used, in which plastic or porcelain
tooth-coloured material is attached to
the surface of the tooth.
film badgeA device that enables hos-
pital staff members to monitor their
exposure to radiation. Film badges are
worn by those people who work in X-ray
and radiotherapy departments. A badge
consists of a piece of photographic film
in a holder worn on the clothing. The
film has a fast (sensitive) emulsion on 1
side and a slow emulsion on the other.
Small doses of radiation blacken only
the fast emulsion; higher doses start to
blacken the slow emulsion and make
the fast emulsion opaque.
finasterideA specific enzymeinhibitor
drug that prevents testosteronefrom being
converted into the more potent male
hormone, dihydrotestosterone. The drug
is used to treat noncancerous prostatic
enlargement (see prostate, enlarged), im-
provingthe flow of urine.Side effects
includeimpotence and decreased libido
and ejaculate volume.
fingerOne of the digits of the hand. Each
finger has 3 phalanges (bones), which join
at hinge joints moved by muscle tendons,
and an artery, vein, and nerve running
down each side. The entire structure is
enclosed in skin with a nailat the tip.
Common finger injuries are lacerations,
fractures, tendon ruptures, and mallet
finger. Infections such as paronychia can
occur, and inflamed flexor tendons may
cause trigger finger. Congenital finger
disorders include syndactyly, polydactyly,
missing fingers, or a webbed appearance
due to deep membrane between the fin-
gers; other finger disorders include
rheumatoid arthritis, osteoarthritis, Ray-
naud’s disease, and dactylitis (swelling)
due to sickle cell anaemia. Clubbing of
the fingers is a sign of chronic lung dis-
ease or some forms of congenital heart
disease. Tumours of the finger are rare
but may occur in chondromatosis.
finger-joint replacementA surgical
procedure in which one or more arti-
ficial joints made of metal, plastic, or
silicone rubber are used to replace fin-
ger joints destroyed by disease, usuallyrheumatoid arthritis or osteoarthritis.
The procedure is usually successful in
relieving arthritic pain and enabling the
patient to use his or her hands again,
but it rarely restores normal movement.
fingerprintAn impression left on a
surface by the pattern of fine curved
ridges on the skin of the fingertips. The
ridges occur in 4 patterns: loops, arches,
whorls, and compounds (combinations
of the other 3). No 2 people, not even
identical twins, have the same finger-
prints. (See also genetic fingerprinting.)
first aidThe immediate treatment of any
injury or sudden illness before profes-
sional medical care can be provided.
Most first aid consists of treating minor
injuries and burns, and fractures.
The aims of first-aid treatment in an
emergency are to preserve life, to pro-
tect the individual from further harm, to
provide reassurance, to make the victim
comfortable, to arrange for medical
help, and to find out as much as possible
about the circumstances of the accident
or injury. Various techniques can be used
to achieve these aims. For example, the
recovery position helps to maintain an
open airway in an unconscious person
who is breathing; artificial respirationis
necessary if a person is not breathing.
Cardiopulmonary resuscitationis essen-
tial if a person is not breathing and has
no heartbeat. Heavy bleeding can lead to
shockbut can be controlled by applying
pressure at appropriate pressure points.
fish oilA product occurring naturally in
some species of oily fish such as mack-
erel. Fish-oil preparations, which are
rich in omega-3 triglycerides, are used
as lipid-lowering drugs.
fistulaAn abnormal passage from an
internal organ to the body surface or be-
tween 2 organs. Fistulas may be present
from birth or may be acquired as a result
of tissue damage. Congenital types in-
clude tracheoesophageal fistulas, branchial
fistulas (see branchial disorders), and
thyroglossal fistulas (see thyroglossal
disorders). Acquired fistulas may result
from injury, infection, or cancer. Fistulas
between the intestine and the skin may
occur in Crohn’s disease. Some types of
arteriovenous fistula(between an artery
and a vein) are surgically constructed toFILM BADGE FISTULAF