Damage or severance of
conducting fibres within a
result of trauma, causing loss of skin
sensation and muscle power. (See
for nerve damage from causes
other than injury.)
If a peripheral nerve (a nerve outside
the brain or spinal cord) is only partially
severed, the cut fibres may be able to
regenerate. Provided the severed ends
are still aligned, new fibres can grow
across the cut to rejoin the connection,
restoring function. If a nerve is totally
severed, the individual fibres cannot
regenerate successfully and there is no
recovery of function. Nerve tracts within
the brain and spinal cord are structural-
ly different from the peripheral nerves,
and severed fibres in these tracts do not
regenerate. For example, vision cannot
be restored if the
can sometimes be used
to stitch a severed peripheral nerve into
place, but recovery is rarely complete.
Compression or stretch-
ing of a nerve, causing numbness,
tingling, weakness, and, sometimes, pain.
Common examples of a trapped nerve
carpal tunnel syndrome
pressure on the median nerve as it
passes through the wrist causes symp-
toms in the thumb, index, and middle
in which pressure
on the nerve root leading from the spinal
cord produces symptoms in the back
and legs; and
, in which the
radial nerve presses against the humerus
(upper-arm bone), producing symptoms
in the wrist and hand.
A damaged nerve may take some time
to heal. In severe cases, surgical decom-
pression to relieve pressure on the nerve
may be necessary.
term used to describe unusual behav-
iour (such as episodes of tearfulness or
shouting and screaming) that may be
part of a crisis of severe
, or other psychiatric illness. The
condition affects the sufferer's ability to
cope with everyday life.
A nontechnical term
for the increased drive and activity of
individuals who are always restless,
anxious, and on the go.
A nontechnical term for
a minor repetitive movement or activity.
Sometimes a nervous habit consists of
involuntary twitches and facial tics,
such as in
Giles de la Tourette's syn-
and some forms of
Voluntary nervous habits, such as
, are common
in young children.
All nervous habits increase during
periods of tension or anxiety, and may
be severe in some forms of
, or drug withdrawal.
The body system that
gathers and stores information and is in
overall control of the body.
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