IMPLANT
INCISIONAL HERNIA
antibiotics are usually given. To prevent
spread of the infection, towels, flannels,
and pillowcases should not be shared.
Children should not go to school or mix
with others until they have been treated
for the condition.
implant
Any material, either natural or
artificial, inserted into the body for
medical or cosmetic purposes. For exam-
ple, artificial joints can replace diseased
structures and breast implants can
improve appearance. Implants are also
used to maintain proper functioning of
an internal organ, treat certain disor-
ders, or deliver drugs or hormones.
implantation,
egg
Attachment of a
fertilized
ovum
(egg) to the wall of the
uterus
.
It occurs about
6
days after
fertil-
ization
,
when
the
blastocyst
(early
embryo) comes into contact with the
wall of the uterus. As the cells of the
developing
embryo
continue to divide,
the outer cell layer penetrates the lining
of the uterus to obtain oxygen and
nutrients from the mother's blood; later,
this layer develops into the
placenta
.
The
embryo usually implants in the upper
part of the uterus; if it implants low down
near the cervix,
placenta praevia
may
develop. Rarely, implantation occurs out-
side the uterus, possibly in a fallopian
tube, resulting in an
ectopic pregnancy
.
implant, dental
A post, surgically em-
bedded in the jaw for the attachment of
a dental prosthesis (an artificial tooth).
Titanium or synthetic materials may be
used. A dental implant is fitted under
local
anaesthesia
. A hole is drilled in the
jaw and a post inserted. Several months
later, an attachment that protrudes from
the gum is screwed into the post; a few
weeks after that, the prosthesis is fitted.
impotence
Inability to achieve or main-
tain an
erection
, usually caused by
psychological factors, including concerns
about performance or relationship diffi-
culties. In about 1
in 10 cases, the cause
is a physical disorder, such as
diabetes
mellitus
, or a neurological disorder, such
as damage to the
spinal cord
. Some drugs
cause impotence as a side effect, but this
reverses when the drugs are stopped.
Treatment may include
counselling
or
sex therapy
for psychological problems.
The drug
sildenafil
is used to treat both
organic and psychological impotence, but
side effects may occur. Other treatments
include self-administered injections into
the penis and a surgical implant, which
can produce a sustained erection.
impression, dental
A mould taken of
the
teeth
,
gums
, and
palate
. A quick-set-
ting material, such as alginate, is placed
in a mould over the teeth. The mould is
removed, and plaster of Paris is poured
into it to obtain a model of the area.
This model is then used as a base on
which to build a
denture
,
bridge
, or den-
tal
inlay
. Dental impressions are also
used in
orthodontics
to study the position
of the teeth and to make
orthodontic
appliances
to correct irregularities.
incest
Sexual intercourse between close
relatives, such as with a parent, a son or
daughter, a brother or sister, an uncle or
aunt, a nephew or niece, or a grandpar-
ent or grandchild. It is illegal or taboo
in most societies and against the teach-
ing of many religions.
incidence
One of the 2 principal mea-
sures (the other is
prevalence
) of how
common a disease is in a defined popu-
lation. The incidence of a disease is the
number of new cases that occur during
a given period (for example, 17 new
cases per
100,000
people per year).
incision
A cut made into the tissues of
the body by a scalpel (surgical knife).
Most incisions are made to gain access
to tissue inside the body, usually to
repair or remove a diseased organ. An
incision may also be made to allow pus
to drain from an
abscess
or boil.
incisional hernia
A type of
hernia
in
which the intestine bulges through a
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