This article is from the Piano General Topics FAQ, by Isako Hoshino email@example.com with numerous contributions by others.
Here's an excerpt from "The Complete Canadian Health Guide":
"...Carpal tunnel syndrome (CTS) is an easily treatable wrist
and hand disorder, more frequent in women than in men. The
problem arises through compression of the median (arm) nerve
in its narrow passageway through the wrist, often starts up
in mid-life to old age and generally affects both hands, the
dominant (most-used) more severely. CTS can arise from
certain jobs or hobbies where repeated movements or
vibrations inflame the wrist tissues - for instance,
knitting, computer keyboard work, driving or operating
certain hand held tools such as drills, hammers, chain saws.
The disorder is frequently seen among miners, roadmenders and
others whose jobs involve use of hand-held tools that
"The first hint of CTS is a sensation of numbness or pain,
usually on first awakening - as if parts of the hand had
'gone to sleep' - typically felt in the thumb and index
finger, but sometimes all the fingers tingle. The tingling
sensation worsens on flexing or extension of the wrist,
subsiding when the hand is bent inwards or at rest (in a
"Numbness from carpal tunnel syndrome may appear after any
movement that keeps the wrist overexerted for long periods:
stitching, painting, doing manicures or giving a massage.
Besides being annoying, the loss may lead to burns (due to
lessened sensation of heat, pain, pressure), and the muscle-
wasting can make wrist movements clumsy. As CTS progresses,
wrist and thumb strength may seriously decline. The reduced
grip may make it difficult to grasp even light objects.
"The tingling can be set off or worsened by anything that
makes the wrist tissues swell and compress the median nerve.
Fluid accumulation during pregnancy or before a menstrual
period, a Colles' (wrist-bone) fracture, gout, rheumatic
(arthritic) swelling, and adrenal or thyroid disease are
"Diagnosis of CTS is relatively easy by the typical night-
time or early-morning hand tingling, use of Phalen's test
(flexing the hands at a 90-degree angle to see if and when
tingling occurs) and Tinel's test (tapping the median nerve
at the wrist to see if and how strongly it produces
tingling). The sooner the tingling appears, the more serious
the condition. Confirmation is with a nerve-conduction study
and electromyogram (EMG), in which small electric shocks are
applied at different spots along the median nerve and the
muscle twitch is charted to show whether, and to what extent,
the hand muscle has retained or lost its nerve supply.
"Treatment for carpal tunnel syndrome can be conservative:
wearing a light plastic wrist splint at night, taking anti-
inflammatory medication by mouth or injection into the wrist,
altering sleep positions and avoiding movements that worsen
the disorder. With correct therapy, time and patience, the
loss of nerve conduction can often be reversed. Sometimes
operating tools in a better, more neutral wrist position
helps to alleviate the problem. Modern designers are working
on vibration dampers, shock absorbers and other ways to
lessen the damaging vibrations of hand-held tools.
"If other methods fail to correct CTS, surgery to decompress
the nerve may be suggested - a simple procedure done under
general or local anesthetic that frees the trapped nerve and
usually provides rapid relief. After a few days, stitches are
removed, but splints may be needed until the wounds heals..."