RADIUS
RATS, DISEASES FROM
RADIUS
radius The shorter
of the 2 long bones
of the forearm; the
other is the ulna.
The radius is the
bone on the thumb
side of the arm. It
articulates with the
humerus at the el-
bow and the carpal
bones at the wrist.
It takes most of the
strain when weight
is placed on the
wrist and is a com-
mon site of fractures
(see
radiusfracture
of; CoUes' fracture).
radius, fracture of
A common type of
fracture that may
affect the lower end,
upper end, or shaft
of the
radius.
Fracture of the radius just
above the wrist (see
CoUes' fracture)
is
the most common of all fractures in
people over 40. Fracture of the head of
the radius just below the elbow is one
of the most common fractures in young
adults. Treatment involves immobilizing
the broken bone in a
cast
or surgically.
Healing takes approximately 6 weeks,
radon A colourless, odourless, tasteless,
radioactive gaseous element produced
by the radioactive decay of
radium.
randomized controlled trials A form
of
controUed trial
that evaluates the
effectiveness of a drug, or other treat-
ment, in which subjects are randomly
allocated to one of the study groups.
This random allocation means individu-
als are equally likely to be selected for
the particular treatment being investiga-
ted or for the control group of the trial,
ranitidine An
ulcer-healing drug
belong-
ing to the
H2-receptor antagonist
group.
It is used to prevent and treat
peptic
ulcers
and to treat
oesophagitis.
Side
effects may include headache, skin rash,
nausea, constipation, and lethargy,
rannla A
cyst
in the floor of the mouth,
which produces a translucent bluish
swelling. Ranulas probably arise from
damage to a
salivary gland.
They are
removed surgically.
R
rape Sexual intercourse with an unwill-
ing partner, which is achieved by the
use or the threat of force or violence,
rash A group of spots or an area of red,
inflamed skin. A rash is usually tempo-
rary and is only rarely a sign of a serious
underlying problem. It may be accom-
panied by itching or fever.
Rashes are classified according to
whether they are localized (affecting a
small area of skin) or generalized (cov-
ering the entire body), and the type of
spots. A bullous rash has large blisters,
a vesicular rash has small blisters, and
a pustular one has pus-filled blisters. A
macular rash consists of spots level
with the surrounding skin and dis-
cernible from it by a difference in colour
or texture. Nodular and papular rashes
are composed of small, raised bumps.
Rashes are the main sign of many
infectious diseases (such as
chicken-
pox),
and are a feature of many
skin
disorders,
such as
eczema
and
psoriasis.
They may also indicate an underlying
medical problem, such as the rashes of
scurvy
or
peUagra,
which are caused by
vitamin deficiency. The rashes of
urti-
caria
or contact
dermatitis
may be
caused by an allergic reaction. Drug
reactions, particularly to
antibiotic drugs,
are a common cause of rashes.
A diagnosis is based on the appear-
ance and distribution of the rash, the
presence of any accompanying symp-
toms, and the possibility of allergy (for
example,
to drugs). Any underlying
cause is treated if possible. An itching
rash may be relieved by a lotion, such
as
calamine,
or an
antihistamine drug.
RAST An abbreviation for radioallergo-
sorbent test. RAST is a type of
radio-
immunoassay
used to detect antibodies
to specific
antigens.
rats, diseases from Rats are rodents
that live close to human habitation.
They damage and contaminate crops
and food stores and can spread disease.
The organisms responsible for
plague
and a type of
tj/phus
are transmitted to
humans by the bites of rat fleas.
Lep-
tospirosis is
caused by contact with
anything contaminated by rat's urine.
Rat-bite fever is a rare infection trans-
mitted directly by a rat bite. There are 2
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