SPINAL ANAESTHESIA
SPINAL NERVES
S
spinal
anaesthesia Injection
of an
anaesthetic into the cerebrospinal fluid
in the spinal canal to block
pain
sensa-
tions before they reach the
central
nervous system.
It is used mainly during
surgery on the lower abdomen and legs.
(See also
epidural anaesthesia.)
spinal cord A cylinder of
nerve
tissue
that runs from the
brain
, down the cen-
tral canal in the
spine
to the
1
st lumbar
vertebra. Below that, the nerve roots con-
tinue within the canal as
cauda equina.
Grey matter, the spinal cord's core, con-
tains the cell bodies of nerve cells.
Areas of white matter (tracts of nerve
fibres running lengthwise) surround the
grey matter. Sprouting from the cord on
each side at regular intervals are the sen-
sory and motor spinal nerve roots. The
small nodule (ganglion) in each sensory
root comprises nerve cell bodies. Nerve
roots combine to form the
spinal nerves
that link the spinal cord to all regions of
the trunk and limbs. The entire spinal
cord is bathed in
cerebrospinal fluid
and
surrounded by the
meninges
.
The nerve tracts in the white matter act
mainly as highways for sensory informa-
tion passing up to the brain or motor
signals passing down. However, the cord
processes some sensory information
itself and provides motor responses
without involving the brain. Many
reflex
actions are controlled in this way.
The spinal cord may be injured by
trauma (see
spinal injury
); spinal-cord
infections such as
poliomyelitis
are rare
but can cause serious damage.
spinal fusion Major surgery to join 2 or
more adjacent
vertebrae.
It is perfor-
med if abnormal movement between
adjacent vertebrae causes severe back
pain or may damage the spinal cord.
spinal injury Damage to the
spine
and
sometimes to the
spinal cord
. Spinal
injury is most often the result of falling
from a height or of a road traffic accident.
Damage to the
vertebrae
and their
liga-
ments
usually causes severe pain and
swelling of the affected area. Damage to
the spinal cord results in
paralysis
and/or
loss of sensation below the site of injury.
X-rays
of the spine are carried out to
determine the extent of damage. If the
bones are dislocated, surgery is needed
to manipulate them back into position.
Treatment with the drug
methylpred-
nisolone
within a few hours of an injury
aids recovery from spinal-cord damage.
Surgery may be needed to remove any
pressure on the cord, but damaged nerve
tracts cannot be repaired.
Physiotherapy
may stop joints locking and muscles
contracting as the result of paralysis.
If there is no spinal-cord damage,
recovery is usually complete. In cases of
spinal-cord damage,
some improve-
ment may occur for up to
12
months.
spinal nerves A set of 31 pairs of
nerves
that connect to the
spinal cord
. Spinal
nerves emerge in
2
rows from either side
of the spinal cord and leave the
spine
through gaps between adjacent
verte-
brae.
The nerves then branch out to
supply all parts of the trunk, arms, and
legs with sensory and motor nerve fibres.
SPINAL CORD
Spinal
Sensory
nerve root ,
, Grey matter
. White matter
G
a
n
g
l
io
n
OF SPINAL CORD
Meninges
STRUCTURE
Motor
nerve
root
520
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