LUMBOSACRAL SPASM
LUNG, DISORDERS OF
other substances. Lumbar puncture is
usually carried out to collect a sample
of cerebrospinal fluid in order to diag-
nose and investigate disorders of the
brain and spinal cord (such as
meningi-
tis
and
subarachnoid haemorrhage
).
The
procedure takes about 15 minutes and
is carried out under local
anaesthesia
.
lumbosacral spasm
Excessive tight-
ening of the muscles that surround and
support the lower region of the
spine
,
causing
back pain
.
Treatment of lumbo-
sacral spasm may include
analgesic drugs
and
muscle-relaxant drugs
.
lumen
The space within a tubular organ,
such as the intestine.
lumpectomy
A surgical treatment for
breast cancer in which only the cancerous
tissue is removed. (See also
mastec-
tomy
;
quadrantectomy.
)
lunacy
An outdated term for serious
mental disorder.
lung
One of the 2 main organs of the
respiratorysystem
. The lungs supply the
body with the oxygen needed for
aero-
bic
metabolism and eliminate the waste
product carbon dioxide. Air is delivered
to the lungs via the
trachea
(windpipe);
this branches into
2
main bronchi (air
passages), with
1
bronchus
supplying
each lung. The main bronchi divide again
into smaller bronchi and then into bron-
chioles, which lead to air passages that
open out into grape-like air sacs called
alveoli (see
alveolus, pulmonary
). Oxy-
gen and carbon dioxide diffuse into or
out of the blood through the thin walls
of the alveoli. Each lung is enclosed in a
double membrane called the
pleura
; the
two layers of the pleura secrete a lubri-
cating fluid that enables the lungs to
move freely as they expand and contract
during breathing. (See also
respiration.)
lung cancer
The most common form of
cancer
in the UK. Tobacco-
smoking
is
the main cause. Passive smoking (the
inhalation of tobacco smoke by non-
smokers) and environmental pollution
(for example, with radioactive minerals
or asbestos) are also risk factors.
The first and most common symptom is
a cough. Other symptoms include cough-
ing up blood, shortness of breath, and
chest pain. Lung cancer can spread to
other parts of the body, especially the
liver, brain, and bones. In most cases,
the cancer is revealed in a
chest X-ray
.
To confirm the diagnosis, tissue must be
examined microscopically for the pres-
ence of cancerous cells (see
cytology
). If
lung cancer is diagnosed at an early
stage,
pneumonectomy
(removal of the
lung) or
lobectomy
(removal of part of
the lung) may be possible.
Anticancer
drugs
and
radiotherapy
may also be used.
lung, collapse of
See
atelectasis; pneu-
mothorax
.
lung disease, chronic obstructive
See
pulmonary disease, chronic obstructive
.
lung, disorders of
The most common
lung
disorders are infections. These dis-
eases include
pneumonia
,
tracheitis
, and
croup
.
Bronchitis
and
bronchiolitis
, which
are inflammatory disorders affecting the
airways within the lungs, can be compli-
cations of colds or
influenza
. The disorder
bronchiectasis
may occur as a complica-
tion of severe bacterial pneumonia or
LUNG
Trachea
Left lung
Bronchus
LOCATION
Lobe
Blood
vessel
ALVEOLI
Bronchiole
Right lung
Thin wall
of alveolus
Air space
Pleura
347
previous page 345 BMA Illustrated Medical Dictionary read online next page 347 BMA Illustrated Medical Dictionary read online Home Toggle text on/off