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Your Hands
Carpal Tunnel Syndrome And Related Conditions Are Easier
To Prevent Than Cure
by Siana Goodwin & Jeffrey Burch
Published in
Massage & Bodywork, Dec/Jan 2003
Reprinted here with
permission of the author
Siana Goodwin has been practicing
Rolfing® for more than twenty years. In 1992 she began
working with Starkey Laboratories, Inc. Starkey Labs,
based in Eden Prairie, MN, is one of the world's largest
manufacturers of custom hearing aids. Her work there
pioneered the application of Rolfing® practices to
address repetitive stress injuries in industry. After
less than a year, the incidence and cost of such
injuries dropped dramatically, resulting in much lower
insurance costs for the company. Siana has been an
assistant teacher of basic Rolfing classes, has taught
and continues to teach workshops on working ,with RSI.
She currently practices in Minneapolis, MN, and is on
the faculty of the American Academy of Acupuncture and
Oriental Medicine, teaching Surface Anatomy.
Illustrations:
by Peter Anthony
Introduction
Massage therapists often assist their
clients in prevention of and recovery from Carpal Tunnel
Syndrome (CTS) and related repetitive strain injuries.
Ironically, massage therapists are also at risk for the
development of CTS, which may shorten or end their
careers. This article describes the anatomy and
biomechanics of CTS and related syndromes. From
understanding the structural and behavioral origins of
this cluster of disorders preventive methods are
described.
Although people often say, when they
have problems with their hands, that they have "carpal
tunnel", this name refers to a specific anatomical
structure. The phrase "carpal tunnel syndrome" (CTS)
refers to a particular dysfunction of the median nerve.
Generalized hand and wrist pain, sometimes accompanied
by numbness, is more accurately called "repetitive
motion (stress) injury" (RMI or RSI).
Structure of the Carpal Tunnel
The "carpal tunnel" is a structure in the
wrist, where the tendons of the finger flexors and the
median nerve pass over the wrist bones. The median nerve
supplies most of the muscle enervation in the hand and
fingers.
The floor of this "tunnel" is formed
by wrist (carpal) bones, and wrist bones define its
sides laterally. The top of the "tunnel", however, is
formed by a broad ligament. This ligament connects to
the scaphoid, trapezoid, hamate and pisiform bones of
the wrist, and also provides a base of support for
muscles of the thumb and little finger. (See Fig. 1) We
will discuss the importance of this further on in this
article.
FIG. 1A: Palmar view of the skeletal hand. |
FIG. 1B: Proximal view of the carpal tunnel. |
The bellies of the muscles that flex
the fingers (flexor digitorum superficialis and flexor
digitorum profundus) lie in the anterior side of the
forearm. The force of these muscles is transmitted to
the finger bones via eight long tendons. At the carpal
tunnel, these tendons are stacked on top of each other,
with the median nerve above them. (See Fig. 2) In
addition, the tendons of flexor carpi radialis and
flexor policis longus also pass through the carpal
tunnel. These tendons are enveloped in synovial sheaths,
which facilitate the tendons' gliding motion of flexion
and relaxation.
FIG. 2A: Carpal tunnel proximally, including
tendons and nerve. |
FIG. 2B: The palmar aspect of the hand,
showing the course of the median nerve. |
Development of RSI and CTS
Irritation from overuse or pressure
within the carpal tunnel can cause tendons to become
inflamed. Even a slight swelling from inflammation can
affect all the structures within the carpal tunnel,
impairing the movement and function of both tendons and
nerve. A vicious cycle of re-injury can be set in motion
as one continues to use their hands and irritate the
tendons.
At this point, there may be pain,
stiffness, and numbness in the hands and fingers caused
by pressure within the carpal tunnel. This condition may
be diagnosed as tendonitis or repetitive motion injury.
When prolonged swelling of the tendons and irritation of
the median nerve results in impairment of the median
nerve function, full-blown carpal tunnel syndrome
develops. The symptoms of CTS include persistent
numbness and pain in the hands that is unrelieved with
rest. In advanced cases the muscles of the thumb, which
are innervated by the median nerve, may atrophy.
It is often difficult to successfully
treat CTS. Anti-inflammatory medication may be useful,
but cannot be used over a long period of time. Direct
injections of anti-inflammatory steroids into the wrist
area is painful, and, again, is not a procedure that can
be repeated frequently. A surgical approach is to
lengthen the ligament forming the palmar boundary of the
carpal tunnel, thereby increasing the volume in the
tunnel. As this surgery has gotten more refined with
arthroscopic techniques, it is quite often successful.
However, given that a great deal of pain and restriction
of motion may lead up to this surgery, it's better to
consider prevention rather than cure!
To develop a plan to prevent RSI,
think again of how this cycle of injury develops by
irritation of tendons and nerves through repeated
motion. Obviously, avoiding repetitive movements is one
way to minimize the danger of developing RSI. However,
there are other factors to be considered as well.
Irritation of tendons and nerves often starts because
there is a poor blood supply to the hands. When blood
supply is restricted by static body posture and/or poor
body mechanics, the danger of developing RSI is
increased.
Prevention of RSI includes avoiding
repetitive motion whenever possible, taking care to
stretch stressed areas or balance repetitive motions
when you can't avoid them, using good body mechanics,
and resting appropriately. Repetitive strain can be
avoided!
Preventing RSI
Avoid direct pressure on the carpal area
Pressure directly on the carpal tunnel ligament
compresses the space of the carpel tunnel. CranioSacral
Therapists and others who have their hands under the
body for long periods know how painful or deadening this
can be to the hands. Avoid using your hands under the
body with weight on the wrist. Most work done with the
hands under the body can be done with the person in a
side - lying or prone position.
FIG. 3A: Rock and glide with hands under
body.
FIG. 3B: Rock and glide
in side-lying position |
Working on a keyboard In the days
before computers, when typewriters were in use, CTS was
rare. Typists' hands were always in motion, moving
slightly up and down the keyboard, and suspended above
it. With computer keyboards, we are much more likely to
rest our hands when we type. RSI may easily develop from
the combination of enforced stillness and the
possibility of restricting circulation. This is
exacerbated when the hand or wrist rests on a hard
surface.
FIG. 4A: Hands in
motion on typewriter. |
FIG. 4B Hands in motion
on keyboard, base of hand resting. |
FIG. 4C: Hands in
motion on keyboard, base of hand in air. |
It may seem that one solution, then,
is to rest the hands on a soft surface! Soft rests have
been developed to put under the base of the hand and
wrist when using a keyboard. Initially these may provide
some relief from RSI symptoms. However when the base of
the hand is rested on a soft surface the bones on the
sides of the tunnel sink in and the central span of the
tunnel may receive more pressure.
If you use a keyboard treat it like a
typewriter. If it is adjustable set it to require more
force. Keep your wrists above the keyboard. This usually
requires lowering the keyboard below the desk surface
height, easily accomplished with a sliding keyboard
tray. Additionally, using a chair with arms that support
the elbows allows the wrists to have more mobility.
FIG. 5A: Resting the wrist on a hard surface
may feel uncomfortable over the bones, but
protects the carpal tunnel. |
FIG. 5B: Resting the wrist on a soft surface
feels good over the bones, but puts ore pressure
on the carpal tunnel. |
A second kind of RSI problem can occur
when the base of the hand at the little finger rests
continually on either a hard or soft surface. The ulnar
nerve is relatively close to the surface of the body at
the medial side of the palm, and can be pressed against
the hamate bone when this part of the hand is
continually pressed against some surface, especially if
weight rests on it. Since this doesn't involve
restriction at the carpal tunnel, it's often overlooked,
but pain, numbness, and tingling in the ring finger and
little finger can often be traced to compression in this
area.
Wrist extension is more harmful than
flexion The carpal tunnel is under the least strain when
the wrist is near a neutral position. When the wrist is
flexed, compression on the carpel tunnel is increased.
However, when the wrist is extended compression on the
carpel tunnel is three times as great as when the wrist
is flexed.
FIG. 6A: Wrist flexion. Carpal tunnel
pressure.
FIG. 6B Wrist extension. Triple Carpal tunnel
pressure.
FIG. 6C: Wrist in
neutral. No carpal tunnel pressure. |
Many massage therapists extend the wrists
in order to bring pressure to a particular area of the
body. This can happen when you bring your weight
directly down into your hands. Try altering your body
stance so that you remain centered and can apply
pressure with the wrists in a near-neutral position.
When you deviate from neutral choose flexion in
preference to extension. When you must extend your
wrists limit the time spent extended to a minimum.
Gorillas have the good sense to walk on their knuckles
rather than their palms, and when was the last time you
heard of a gorilla with CTS?
Avoid repetitive motion by making
small variations
While it is important to have the wrists
spend most of their time near neutral it is also
important to vary the position and use of your hands.
Remember that many RSI problems begin with decreased
blood flow. Keeping a variety of positions and movements
in your working repertoire can help prevent this. Using
only one position, even an ideal position, is repetitive
stress. Try to use the wrist in many positions near
neutral, but only occasionally exactly on neutral. More
positions toward mild flexion should be chosen rather
than toward mild extension. However it is well to
occasionally use mild extension to help counteract other
habitual movements.
The problem of the opposable thumb - Our
prehensile thumbs allow us much greater dexterity than
other creatures. However, overuse of this gift may
contribute to RSI. Remember that the muscles that allow
opposition of the thumb and fifth finger (opponens
pollicis, opponens quinti digiti minimi), as well as the
intrinsic flexors of the thumb and little finger, arise
from the carpal ligament. Prolonged use of these muscles
may result in chronic contraction. This chronic
contraction may also affect the flexibility and
resilience of the carpal ligament. Observe that when you
bring the thumb and little finger together, the base of
the hand narrows. This narrowing compresses the carpal
tunnel area. When this narrowing
becomes chronic, the carpal tunnel is chronically
restricted.
Two kinds of hand motion involving the thumb can be hazardous. Gripping,
using all fingers of the hand and the thumb, requires
contraction of the tendons that go through the carpal
tunnel. However, it doesn't restrict the carpal ligament
in the same way as do opposition or pinching movements,
which involve the motion of the thumb toward the midline
of the hand. Both can produce RSI symptoms, though, and
prolonged use of either should be avoided. When you are
working on clients avoid using a lot of kneading or
pinching movements. Watch for unconsciously holding the
hand in a flexed position with the base of the hand
narrowed. Avoid this.
Additional Factors in RSI
Although we've focused on problems
associated with the carpal tunnel, the median nerve and
tendons of the finger flexors may be affected by
conditions elsewhere in the body. Compression of blood
flow or irritation to the nerve may occur anywhere along
the course of the nerves and arteries. This may not be
noticeable until it is magnified by entrapment in the
carpal tunnel, but knowledge of how these factors affect
the health of nerves and tendons is an important part of
prevention.
Pronation and Supination Immediately
proximal to the hand are the ulna and the radius. In the
motions of pronation and supination the full length of
the radius rotates, but the rotation is of a different
kind at each of the two ends of the radius. At the elbow
end of the forearm the radius rotates around its own
axis within the annular ligament. At the wrist end of
the forearm the radius rotates around the ulna. This
functional difference between the two ends makes the
shafts of the two bones move closer to each other in
pronation and away from each other in supination. In
pronation, the radius is crossed over the ulna. The
muscular contraction required for this movement
increases pressure in the forearm, and may restrict the
free play of muscles and the blood supply to the forearm
and hand.
You're probably already aware, though,
that most of the activities we do with our hands require
a pronated position. How can we offset the possible
restrictive effects of prolonged pronation? Any degree
of movement toward supination will help. Study the way
you use your hands in bodywork to see if there are times
you could bring your forearm to a neutral (thumb up)
position rather than full pronation. If you have had
trouble with RSI and use a computer a lot, a pyramid
keyboard may also help. And always, frequent small
variations in hand position reduce repetitive strain.
Distal restriction of nerves and
vessels Irritation of nerves and restriction of blood
vessels may also occur in both the elbow and the
shoulder. Compression can occur at the elbow when it is
flexed to less than 90 degrees. This may reduce
circulation to the hand. Poorer nutrition and
oxygenation, the result of reduced circulation, lead to
more tissue irritation in the forearm and hand. Of
course, you don't have to avoid such motions entirely,
just avoid using them for extended periods of time.
Adjust bodywork tables, computer chairs and keyboards,
and the driver's seat and steering wheel of your car so
the elbow can work at greater than 90 degrees.
Also avoid resting the elbows on a
hard surface, especially if they are flexed to greater
than 90 degrees. This motion extends the ulnar nerve
where it runs between the olecranon of the elbow and the
medial epicondyle of the humerus, and it is more
vulnerable to repetitive stress at this point.
An even greater hazard is restriction
at the shoulder. The roots of the nerves of the forearm
and hand arise from the neck and run underneath the
clavicle at the shoulder. This area also contains the
main blood vessels for the arm. When the shoulders are
rounded, or there is tension in the muscles of the neck
and upper shoulders, these important vessels and nerves
may be restricted. Thoracic outlet syndrome, sometimes
seen as a structural problem and sometimes as a form of
RSI, may be caused by constriction of the nerve roots
between the scalene muscles and the first rib. Even when
TOS is not identified, compression and restriction here
may make the nerves and tendons more vulnerable at the
wrist and hand.
FIG. 7A: Areas of
frequent nerve and vascular impingement. |
To minimize the risks of problems in
this area, avoid "hunching over" when you work. Keep the
shoulder girdle relaxed, and your neck straight. Watch
out for "wearing your shoulders around your ears."
Better rest for roomr hands
When you are not working let your hands
rest palm up. This both opens the space between the ulna
and radius, and reduces compression on the palmar
surface of the hand, wrist and forearm. If you are
experiencing pain or numbness in your hands, try resting
your hands on a pillow, either in your lap or while you
lie on your back. This reduces the strain of stretching
the nerves when the arms are completely extended.
In sleeping let your elbows be
extended more than 90 degrees. We all change positions
in sleep 12 - 15 times a night, so the position you
start in is not where you spend most of the night. Yet,
if you begin the night with your hands supinated and
elbows extended that may be 45 minutes of better
position. Every little bit makes a difference. If you
wake during the night you can get another 45 minutes or
so. If you need to go to sleep on your side, avoid
having your elbows flexed and your wrists curled inward.
Don't sleep with your hands under your head.
Everything is connected
Get regular exercise. One factor which
may contribute to carpal tunnel is low cardiovascular
condition of the body. When you are sedentary, not
enough blood circulates in the hand area to support a
high level of activity in the hands.
More hand rest
If you make your living with your hands
avoid using your hands for recreation. Move on from
handball, knitting, woodworking, and jewelry making to
hiking, reading, dancing or spectator sports. If RSI
problems are persistent, consider voice activated
software to reduce use of the computer keyboard.
Gentle Stretching
Very gentle stretching is also effective
in restoring circulation to tissues that have been
traumatized by repetitive motion or compression. The
effective stretch for such injured tissues is a
micro-stretch. Move very slowly into a position that
counteracts the repetitive motion - for instance, if you
have worked with your hands in flexion, move very slowly
into extension. STOP at the first hint of strain in the
movement, then wait until that feeling subsides (usually
about 10 seconds) and move a little further. If you feel
that you are moving in increments of millimeters, you're
probably stretching correctly.
| How to Reduce Hand Strain:
Twelve Big Hints
1. Vary your tasks. Mix
several activities in the course of a day to
reduce repetitive activity.
2. When performing a
repetitive task frequently vary the way you are
using your hands. Even small variations help.
3. Avoid working with your
elbows bent at an angle less than 90 degrees.
Too much bend at the elbow compresses blood
vessels and nerves.
4. Whenever possible, keep
your wrists at an angle near neutral. Flexion
puts strain on the carpal tunnel. Extension
places three times the strain as when the wrist
is flexed.
5. Don't rest your wrists on
surfaces, whether the hand is in neutral or in
pronation. Resting the hand for long periods of
time compresses the carpal tunnel and other
vulnerable structures.
6. When you must use the hand
in pronation, try to vary this with motions that
bring the hand into thumb up position. When you
are able to rest your hands, rest them in
supination.
7. Minimize time spent
contracting or narrowing the palm of the hand,
as in opposition and pinching movements. This
position contributes directly to carpal tunnel
pressure. Adjust your grip position so the thumb
doesn't close tightly across the fingers.
8. Keep your shoulders relaxed
and your neck straight as much as possible to
minimize pressure on nerve and vessel structures
distal to your hands.
9. Breathe! It increases
relaxation and blood oxygenation.
10. If you use a computer for
several hours a day, then own two or three
different mouse styles. Changing your mouse
frequently and adjusting the angle of your hands
often will help reduce repetitive strain.
11. Get regular exercise. One
factor which may contribute to RSI is low
cardiovascular condition of the body. Give your
hands every chance to receive good blood flow.
12. If you experience RSI
symptoms in your job, minimize hobbies which
require intensive hand movements. Play soccer
rather than racquet sports. Sing rather than
play the guitar. |
Bibliography
Butler, Sharon J., Conquering Carpal
Tunnel Syndrome, 1996 New Harbinger Publications, ISBN
1-57224-039-3
Cailliet, R., Hand pain and
impairment, Edition 4, 1994 F.A. Davis, ISBN
0-8036-1619-8
Cailliet, R., Neck and arm pain,
edition 3, 1991 F. A. Davis, ISBN 0-8036-1610-4
Lester, B., The Acute Hand, 1999 Simon
& Schuster, ISBN 0-8385-0258-X
Wilson, F. R., The Hand, 1998 Random
House, ISBN 0-679-41249-2
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