Carpal tunnel syndrome
Carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is a common condition that causes a tingling sensation, numbness and sometimes pain in the hand and fingers.

These sensations usually develop gradually and start off being worse during the night. They tend to affect the thumb, index finger and middle finger.

Other symptoms of carpal tunnel syndrome include:

  • pins and needles (paraesthesia)
  • thumb weakness
  • a dull ache in the hand or arm

Read about the symptoms of carpal tunnel syndrome.

When to seek medical advice

See your GP if you're experiencing persistent symptoms of CTS. They can usually diagnose CTS by asking about your symptoms and examining your hand, wrist or arm.

Further tests in hospital may be required if the diagnosis is uncertain or to help rule out other conditions.

Read about diagnosing carpal tunnel syndrome.

Causes of carpal tunnel syndrome

Carpal tunnel syndrome is caused by compression of the median nerve, which controls sensation and movement in the hands.

The carpal tunnel is a narrow passage in your wrist made up of small bones and a tough band of tissue that acts as a pulley for the tendons that bend the fingers.

In most cases, it isn't known why the median nerve becomes compressed. However, some things do increase the risk of CTS.

This includes:

  • a family history of CTS
  • pregnancy – up to about 50% of pregnant women develop CTS
  • injuries to the wrist
  • other health conditions, such as diabetes and rheumatoid arthritis
  • strenuous, repetitive work with the hand

CTS is more common in women and becomes more likely as you get older.

Read about the causes of carpal tunnel syndrome.

Treating carpal tunnel syndrome

In some cases, CTS disappears without treatment, or the symptoms reduce by introducing simple self care measures.

CTS in pregnant women often gets better within three months of the baby being born. Treatment may be needed if it persists for more than a few months after delivery.

Non-surgical treatments, such as wrist splints and corticosteroid injections, are effective for some people with CTS.

Surgery may be required if these treatments fail to relieve the symptoms. It may also be used if there's a risk of permanent nerve damage.

Read about treating carpal tunnel syndrome.

Surgery relieves the symptoms of mild CTS immediately. People with severe nerve damage can take a while to recover, or there may not be any improvement.

Depending on which hand was operated on and what your job involves, you'll usually be able to return to work within a few weeks of surgery.

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The main symptoms of carpal tunnel syndrome (CTS) are tingling, numbness and pain in one or both hands. Most cases affect both hands eventually.

The symptoms of CTS most often occur in:

  • the thumb
  • the index finger
  • the middle finger
  • half of the ring finger

However, the tingling and pain can sometimes extend outside this area.

The symptoms of CTS also tend to develop gradually, and usually start off being worse at night or early in the morning.

Any repetitive actions of the hand or wrist can aggravate the symptoms, as can keeping your arm or hand in the same position for a prolonged period of time.

Other symptoms

Other possible symptoms of CTS include:

  • a dull ache and discomfort in the hand, forearm or upper arm
  • a burning, prickling sensation (paraesthesia) in the hand similar to pins and needles
  • dry skin, swelling or changes in the skin colour of the hand
  • becoming less sensitive to touch (hypoaesthesia)
  • weakness and wasting away (atrophy) of the muscles at the base of the thumb

In some cases, you may experience pain that spreads from your hand up to your forearm and elbow.

Using your hands

CTS often affects your dexterity, which is the ability to use your hands effectively to carry out certain tasks. You may find you often drop objects, or have difficulty typing or fastening buttons.

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The symptoms of carpal tunnel syndrome (CTS) are caused by squashing (compression) of the median nerve at the wrist.

The median nerve is responsible for two main functions:

  • carrying physical sensations such as your sense of touch from your hand to your brain
  • carrying nerve signals from your brain to your hand, controlling movement

Any pressure on the median nerve can disrupt the nerve signals, affecting your sense of touch and hand movements. 

The median nerve can become compressed if the tissues inside the tunnel become swollen or the tunnel narrows over time.

Increased risk

In most cases, it's not known what causes the median nerve to become compressed, although a number of things increase the risk of developing CTS.

These include:

  • family history
  • certain health conditions, such as diabetes, an underactive thyroid gland or rheumatoid arthritis
  • pregnancy
  • certain injuries to the wrist
  • certain activities

These risk factors are outlined below.

Family history

Research has shown there's a genetic link to CTS. This means you may have an increased risk of developing it if other members of your family have the condition or have had it in the past.

About one in four people with CTS have a close relative, such as a parent, brother or sister, who also has the condition. It's not fully understood how and why the condition is passed on through families.

Health conditions

Certain health conditions appear to increase your risk of developing CTS.

These include:

  • diabetes – a chronic (long-term) condition caused by having too much sugar (glucose) in the blood
  • any kind of arthritis – a condition where the joints become painful and inflamed
  • hypothyroidism – an underactive thyroid gland
  • obesity in young people
  • some drugs used to treat breast cancer – such as exemestane (Aromasin)

CTS can also develop when a person has an abnormal wrist structure, such as an unusually narrow carpal tunnel. It can also be a result of cysts, growths or swellings in the carpal tunnel.


CTS is common during pregnancy, although the exact cause isn't known. Many cases resolve after the baby is born.

It's not known whether women who have carpal tunnel syndrome during pregnancy are at greater risk of developing the condition in later life.

CTS is also common in women around the time of the menopause.


CTS can sometimes occur after a hand injury, such as a sprain, fracture or crush injury. This is because the swelling places pressure on the median nerve.

Also, these types of injuries can change the natural shape of the bones and ligaments in the hand, leading to increased pressure on the median nerve.

Certain activities

Certain activities may trigger the development of carpal tunnel syndrome. These tend to involve strenuous grip, bending the wrist repetitively (flexion) and exposure to vibration.

Examples include:

  • playing a musical instrument
  • assembly packing
  • work that involves manual labour 
  • work with vibrating tools, such as chainsaws

However, further research into the link between work-related hand use and CTS is required to determine how important these types of activities are in causing the condition.

Although typing is often thought of as a possible cause of carpal tunnel syndrome, CTS is actually less common in people who type all day than those who carry out more strenuous activities

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Carpal tunnel syndrome (CTS) can usually be diagnosed by your GP, who will examine your hand and wrist and ask you about your symptoms.

Your GP will assess your ability to use your hand, wrist or arm, and look for signs of weakness in the muscles surrounding your thumb.

Physical tests

Your doctor may tap your wrist lightly to see if you feel tingling or numbness in your fingers, although this test isn't reliable.

Flexing your wrist or holding it elevated above your head for a minute are other commonly performed simple tests for CTS. This should induce the same pain, numbness or tingling in your hand if you have the condition.

Any of these sensations may be the result of your median nerve being compressed. A positive result on one of these tests suggests you may have CTS, but doesn't prove it.

Further testing

Further testing for diagnosis is usually only required if your GP is uncertain and wants to rule out other conditions that have similar symptoms.

Blood tests

A blood test can be used if the doctor suspects an underlying condition relating to CTS, such as:

Nerve conduction study

A nerve conduction study is a test that measures how fast signals are transmitted through your nerves.

During the test, electrodes are placed on your hand and wrist, and a small electrical current is used to stimulate the nerves in the finger, wrist and sometimes the elbow.

The results from the test indicate how much damage there is to your nerves.  

Nerve conduction studies are usually performed in hospital and take about 10 minutes. They're generally not very painful, but may be uncomfortable.

Imaging studies

The main imaging method used in CTS is an ultrasound scan, which uses high-frequency sound waves to produce an image of the inside of your body.

This method can be used to see the nerve itself, and can often add further useful information about CTS.

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Treatment for carpal tunnel syndrome (CTS) depends on the severity of the nerve damage and your preferences. In some cases, CTS improves after a few months without treatment.

You should try to avoid any activities that make your symptoms worse.

If your work involves using a computer keyboard, there's little evidence that modifications at your workplace are likely to be of any help in relieving your symptoms.

If symptoms persist, there are a range of non-surgical and surgical treatments available that aim to relieve the pressure on the median nerve.

If CTS is caused by an underlying health condition, such as rheumatoid arthritis, treating the condition should improve your symptoms.

The various treatments for CTS are outlined below.

CTS during pregnancy

If you develop CTS during pregnancy, your symptoms should pass after your baby is born – after about 6 to 12 weeks.

However, if the median nerve is severely squashed (compressed) or the symptoms are long-lasting (chronic), permanent nerve damage and muscle wasting can occur and treatment will be required. 

Non-surgical treatments

Unless there's thought to be an immediate need for surgery, treatments such as wrist splints and corticosteroid injections are often recommended initially.

There's a lack of evidence to support the use of non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen to treat CTS, or for diuretics to help relieve fluid retention.

Wrist splints

A wrist splint is worn to support the wrist and prevent it bending. Bending places pressure on the nerve and aggravates symptoms.

You should begin to notice an improvement in your symptoms within four weeks of wearing the wrist splint.

Wrist splints are usually available from larger pharmacies, or your GP may be able to recommend a suitable supplier. They can also be ordered online.

Read more about splinting for CTS.


Corticosteroids are a type of steroid medication. Steroids are hormones produced naturally in the body. They are powerful chemicals that can help reduce inflammation.

If a wrist splint doesn't work, corticosteroids may be recommended.

Corticosteroids can be taken as tablets, although for CTS it's likely that you'll have a corticosteroid injection directly into your wrist.

One injection is usually recommended to begin with. If the condition responds well to one injection but then recurs, the treatment may be repeated.

Carpal tunnel release surgery

Surgery is usually recommended for cases of CTS when other treatments have failed to relieve symptoms.

Surgery for CTS is known as carpal tunnel decompression or carpal tunnel release surgery, and is performed on an outpatient basis, which means you won't have to stay in hospital overnight.

During surgery, the roof of the carpal tunnel (carpal ligament) is cut to reduce pressure on the median nerve in the wrist.

local anaesthetic is used to numb your hand and wrist, but you'll remain awake throughout the operation.

The surgery can be performed as open surgery, which involves making a single cut in the wrist.

Some surgeons use keyhole surgery, where special instruments and a long tube with a light at one end and an eyepiece at the other are inserted through small cuts in your wrist, and sometimes your palm. 

This allows the surgeon to see the carpal ligament on a monitor throughout the operation.

There are no long-term differences in the outcomes of the two approaches.

Your surgeon will be able to discuss the most appropriate method of surgery with you.

Things to consider

A number of things may affect your decision to have surgery, including:

  • possible complications after surgery
  • the recovery time
  • how successful non-surgical treatments have been

In most cases, carpal tunnel release surgery provides a complete and permanent cure. However, as with any form of surgery there's always a small risk of complications.

Reported complications of CTS include:

  • infection
  • failure to fully separate the roof of the carpal tunnel during surgery, usually resulting in persistent CTS symptoms
  • bleeding after the operation
  • nerve injury
  • scarring
  • persistent wrist pain, which may be different from the original symptoms
  • in rare cases, the return of CTS symptoms long after apparently successful surgery
  • complex regional pain syndrome – a rare but chronic condition that causes a burning pain in one of the limbs

After surgery

There are a variety of different recommendations for postoperative care. There's no evidence that one way is better than another, but your surgeon will give you advice.

The most common advice after carpal tunnel release surgery is to keep your hand in a bandage for a couple of days, and you may need to wear a sling.

You should keep your hand raised for 48 hours to help reduce any swelling and stiffness in your fingers.

Gently exercise your fingers, shoulder and elbow to help prevent stiffness. You may be able to start these gentle exercises on the day of your operation.

After having surgery for CTS, you can use your hand to do light activities that don't cause excessive pain or discomfort.

Try to avoid using your hand for more demanding activities until it's completely recovered, which may take several weeks.

The recovery time for open release surgery is usually slightly longer than the recovery time for keyhole surgery. However, both methods have proven to be equally effective.

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The information on this page has been adapted by NHS Wales from original content supplied by NHS Choices.
Last Updated: 09/11/2016 13:04:13