'''Carpal tunnel syndrome''' is a [[disorder]] in which the [[median nerve]] is compressed at the [[wrist]] causing symptoms like tingling, pain, coldness, and sometimes weakness in parts of the hand. It is the best known of a class of disorders called [[repetitive strain injury|repetitive strain injuries]].

==Anatomy==
The median nerve runs through the [[carpal tunnel]], a canal in the wrist that is surrounded by bone on three sides, and a fibrous sheath (the flexor retinaculum) on the other. In addition to the nerve, many of the hand's [[tendon]]s pass through this canal. The median nerve can be compressed by swelling of the contents of the canal, by soft tissue swelling in and around the tunnel or even by direct pressure from part of a broken or dislocated bone. However, bone dislocations are a rare cause of carpal tunnel syndrome.

==Incidence==

The syndrome is much more common in women than it is in men.

==Symptoms==

The first symptoms usually appear when trying to sleep. Symptoms range from a burning, tingling numbness in the fingers (especially the thumb and the index and middle fingers) to difficulty gripping, making a fist, or dropping things.  Most early sufferers mistakenly blame the tingling numbness on their sleeping position, thinking their hands have had restricted circulation and are "falling asleep".  If left untreated the symptoms often progress to intense pain which restricts hand functionality.  It is known as a hidden disability, because people can do some things with their hands and appear to have normal hand function, but often live with severely restricted hand activity due to the pain.

==Causes==

Some cases of carpal tunnel syndrome are due to work-related cumulative trauma of the wrist. It is commonly caused by strain placed on the hand, for instance gripping and typing, which are usually performed repetitively in a person's occupation.  The condition was first diagnosed in Australia in the 80s when music started to use synthesizers heavily and people using these instruments started to get hand and wrist pain.  The condition went mostly undiagnosed in the US until the mid 90s when computers became more popular in the workplace.

There are a number of causes of carpal tunnel syndrome. They can be either [[Physical trauma|trauma]]tic, or non-traumatic.

Repetitive stress induced carpal tunnel strain is the leading cause of carpal tunnel syndrome in most industrialized countries.  In the USA for instance, repetitive stress induced carpal tunnel syndrome is the biggest single contributing factor to lost time at work.  This type of carpal tunnel syndrome results in billions of dollars of workers compensation claims every year.

Repetitive hand and wrist action often results in subcutaneous tissues becoming injured and swollen.  These tissues include fascia, muscle, ligament, tendon, sheaths, retinaculum and peripheral nerve and blood vessels.  In restricted passages of the body, swollen soft tissue can become compressed together creating intense pressure.  Adjacent soft tissue can adhere together when compressed under these conditions over a prolonged period.  

Trauma-based causes:

*[[Fracture (bone)|Fracture]]s of one of the arm [[bone]]s, particularly a [[Colles' fracture]].
*[[Dislocation]] of one of the [[carpal bone]]s of the [[wrist]].
*[[Hematoma]] forming inside the wrist, because of internal [[haemorrhage|haemorrhaging]].
*Deformities due to abnormal [[healing]] of old bone fractures.


Non-traumatic causes, generally happen over a period of time, and are not triggered by one certain event. Examples include:
* [[Tenosynovitis]], which is [[inflammation]] of the [[joint]]. Part of the process of inflammation is swelling, and this compresses the nerve.
* With [[pregnancy]] and [[hypothyroidism]], fluid is retained in tissues, which swells the joint.
* [[Acromegaly]], a disorder of [[growth hormone]]s, compresses the nerve by the abnormal growth of bones around the hand and wrist.
* [[Tumour]]s (though not necessarily cancer), such as a [[ganglion]] or a [[lipoma]], can protrude into the carpal tunnel, reducing the amount of space.
* [[Diabetes]], [[rheumatoid arthritis]], and [[obesity]] tend to cause swelling, thus decreasing the amount of space in the carpal tunnel.
* [[Idiopathic]] causes, which no-one can explain, can also cause this disease.


Common activities that have been identified as contributing to repetitive stress induced carpal tunnel syndrome include:
* Computer keyboarding or typing
* Playing video games
* Playing a musical instrument
* Driving a vehicle, motorcycle or flying a plane
* Pushing a lawn mower (both the pressure and the vibration are to blame)
* Any activity where hand use is vigorous and routine could contribute (surgeons, dentists)
* An exhaustive list can be found in the external links below

Often people suffering from carpal tunnel syndrome can have multiple contributing factors which are aggravated by vigorous hand activities and repetitive stress trauma to the hand.

Proper attention to [[ergonomic]] considerations can reduce or eliminate these kinds of injuries.

==Diagnosis==

There are two easy methods to test for carpal tunnel syndrome.  One is squeezing or clenching the hand and noticing a lack of strength. 

A second test, known as [[Phalen's maneuver]], is grab the fingers and pull back the hand back, up towards yourself, approaching but not reaching a 90 degree angle. If this position hurts, tingles or burns within the first 10 seconds then carpal tunnel syndrome exists. The quicker the pain starts, the more advanced the condition.

A classic, though less effective method, [[Tinel's sign]], is a way to detect irritated nerves. It is performed by lightly banging (percussing) over the nerve to elicit a sensation of tingling or "pins and needles" in the distribution of the nerve.
In a person with carpal tunnel syndrome where the median nerve is compressed at the wrist, Tinel's sign is often "positive" and causes tingling in the thumb, index, and middle fingers.
Tinel's sign is sometimes referred to as "distal tingling on percussion" or DTP.

==Treatment and Prevention==

The most effective means of treatment and prevention are by proper stretching, changes in diet and reducing or stopping the stress on the muscles in the carpal area.  While there is a surgical relief to carpal tunnel syndrome, full recovery is achieved in less than 60% of cases.  Downtime and rehabilitation can take up to three months.  Also, since carpal tunnel syndrome is a syndrome, not a disease, if repetitive stress activities are continued, then surgery will likely have to be repeated within a year or two.  This makes surgery a poor choice for carpal tunnel syndrome treatment.

One recommended stretching exercise is:
# Sit in a chair. 
# Place the right elbow into your side, palm side of the hand 
facing upwards. 
# Using the left hand, push the right hand down by applying 
pressure to the four largest fingers. 
# Hold for two seconds. 
# Release the stretch by taking the pressure off the fingers and just letting the hand naturally come back. 
# Perform 10 repetitions, switch arm configuration and perform 10 more repetitions.

Changes in diet relate to providing the body with the nutrients it needs to reduce the flamatory action of the carpal muscles in order to reduce pressure on the nerve, thus allowing it to heal.  No specific vitamin or nutrient has been shown to have a noticeable [[anti-inflammatory]] effect but taking a varied multivitamin mix can have a noticeable effect on reducing inflammation in the body.  Using an over-the-counter anti-inflammatory such as [[Aspirin]] can be as or more effective.  Certain vitamins and nutrients can also be taken to repair nerve damage, such as [[amino acids]], [[vitamin B]] complex and [[hypercium]], an extract of [[St John's Wort]].  A more aggressive option is an injection of [[cortisone]], to reduce swelling.  Please note that pain relievers will only mask the pain and only an anti-inflamatory will give the carpal nerve time to heal.

More physical ways to reducing the stress on the carpal tunnel involve adopting a more ergonomic work and life enviroment such as using an ergonomic keyboard (and perhaps switching from a [[QWERTY]] key layout to a more efficient [[Dvorak Simplified Keyboard]] layout).  Studies have shown ergonomic keyboards reduce wrist stress by 30% or more and Dvorak reduces stress an additional 30%.  It's also important that one's body be aligned properly with the keyboard. This is most easily accomplished by bending one's elbows to a 90 degree angle and making sure the keyboard is at the same height as the elbows.  Also it is important not to put physical stress on the wrists by hanging the wrist on the edge of a desk, or exposing the wrists to strong vibrations.

It has been shown that taking multiple mini breaks during the stressfull activity is more effective than taking occasional long breaks.  There are two applications available that allow one to set up a proper breaking schedule by blocking input to the computer.  The first to appear was a commercial solution called [http://www.workpace.com/ WorkPace], which was followed eventually by a free software alternative known as [http://www.workrave.org/ WorkRave].  Both applications have recommended defaults, following the most effective average break configuration which is a 30 sec. pause every 3 to 5 minutes (the more severe the pain, the more often one should take this break).  During this break it would be best to perform a stretching exercise or simply let one's arms dangle to the ground.  Note that one will find these breaks very disruptive at first, but once adjusted to them, they will make a huge difference in carpal tunnel pain, with possibly more stress reduction than all other treatments combined.

The last way to reduce stress on the carpal tunnel is to make use of wrist braces and wear them as much as possible.  Please note that in order for a brace to be effective, it must fully immobilize movement of the wrist.  A brace that goes from the thumb & lower hand to part of the forearm is optimal, these braces are around 6 to 8 inches in length.  Wrist "socks" will not be effective as they do not fully limit wrist movement.  The brace will be most effective if worn at the time of the stressfull activity but their restrictive nature makes it almost impossible to type.  It can be very effective if worn at work or during sleep.

==Long term recovery==

Long-term chronic carpal tunnel syndrome can result in permanent nerve damage.  However, most carpal tunnel syndrome sufferers either change their hand use pattern or posture at work or find a soft tissue therapy that allows them to return to full activity without hand pain and sleep disruption.  Most people end up prioritizing their activities and give up the least important activities so that they can minimize pain and perform the essential tasks.  

Many people change jobs to avoid continued repetitive stress tasks. Some find success by adjusting their repetitive movements, the frequency with which they do the movements, and the amount of time they rest between periods when they perform the movements.  The early signs of carpal tunnel syndrome should not be ignored.  Early denial of carpal tunnel strain is a sure way to lead to full carpal tunnel syndrome.

==See also==
*[[Repetitive strain injury]]

==References==

* [http://www.ninds.nih.gov/health_and_medical/disorders/carpal_doc.htm NINDS Carpal Tunnel Syndrome Information Page]

==External links==

* [http://www.mycarpaltunnel.com/treatment-carpal-tunnel-syndrome.shtml Clinical Study of Soft Tissue Therapy for Treating Carpal Tunnel Syndrome - Dr. Clyde Morgan]

Neuromuscular Re-education (NMR) is a highly specialized soft tissue technique that effectively resolves neck, lower back and extremity pain. The foundation upon which NMR is built is the body's response to inflammation. (http://www.softtissuemonterey.com/neuromuscular.htm)
http://www.indianaphysicaltherapy.com/index.php?id=18 Selective Soft Tissue Therapy]

[http://www.chirotx.com/active_release_technique_carpal_tunnel_novato.htm carpal tunnel syndrome treatment] with [[Active Release Techniques]]
* [http://www.chirotx.com/books/reviews/conquering_carpal_tunnel_syndrome/index.htm Conquering Carpal Tunnel Syndrome] book review
* [http://www.wpangel.com Software helping to adjust workplace for healthy working and make pauses during work (Windows)]

[[de:Karpaltunnelsyndrom]]
[[es:Sindrome del tunel carpiano]]
[[pt:Sindrome do tunel carpal]]
[[fr:Syndrome du canal carpien]]