Carpal tunnel syndrome (CTS) is a painful condition that occurs when the median nerve in the wrist is compressed.

Also known as median nerve entrapment or median nerve compression, CTS may happen when a nerve swells, the tendons become inflamed, or something causes swelling in the carpal tunnel.

Symptoms include tingling, burning, or itching and numbness in the palm of the hand and the fingers, especially the thumb and the index finger.

The National Institute of Neurological Disorders and Stroke describes CTS as the “the most common and widely known of the entrapment neuropathies, in which one of the body’s peripheral nerves is pressed on or squeezed.”

diagram of a hand explaining the symptoms and causes of carpal tunnelShare on Pinterest
Illustration by Sophia Smith

In the United States, CTS affects 1–3 people per 1,000 every year. Most people receive a CTS diagnosis between the ages of 40 and 60 years, and the prevalence increases with age. The condition can appear in one or both wrists. It is also more common in females than in males.

Without treatment, CTS can have a negative impact on a person’s quality of life. Eventually, the median nerve can become severely damaged. Consequently, there may be permanent numbness in the fingers and permanent weakness in the muscles that are innervated by the median nerve.

CTS often results from repetitive wrist movements, and therefore, it is commonly linked to computer use. However, reports date back to the 1800s, and the condition was familiar to orthopedic surgeons before the widespread use of computers.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

CTS symptoms tend to develop gradually over time.

Symptoms may initially appear at night or upon waking up in the morning. Individuals may feel the need to “shake out” their hands when they wake up. The discomfort may wake them repeatedly during the night.

The three main symptoms of CTS are:

  • pain
  • numbness
  • tingling

These symptoms occur in the thumb and the two fingers next to it, as well as in half of the ring finger. They may extend to the rest of the hand and into the forearm.

As the condition progresses, symptoms may persist during waking hours. A person may lose grip strength and find it harder to form a fist or grasp small objects. Opening a bottle of soda, doing up buttons, or typing on a keyboard can become a challenge.

If left untreated, the muscles at the base of the thumb may wither away, and the person may no longer be able to tell hot from cold with the thumb and finger.

Symptoms tend to emerge or get worse after using the affected hand. The sensation of tingling, burning, and pain may worsen if the arm or hand has been in the same position for a long time.

The carpal tunnel, also known as the carpal canal, is a narrow, rigid passageway of bones and ligaments at the base of the hand. The median nerve and tendons are also in the carpal tunnel.

The carpal tunnel can sometimes narrow because the tendons become irritated and inflamed or because some other swelling puts pressure on the median nerve.

Sensations to the palm, the thumb, and three other fingers are controlled by the median nerve. The median nerve also controls the muscle that brings the thumb across the palm to touch the little finger. It does not, however, control the little finger.

Pressure on this nerve can lead to pain, numbness, and weakness in the hand and wrist, and this may cause pain to radiate up the arm and even to the shoulder.

CTS can develop for various reasons. However, it is more likely if a person frequently uses extremes of wrist motion, if they are exposed to vibration, and if they repeatedly use their fingers — for example, when typing.

Sometimes, however, there is no clear cause.

Some of the more common causes of CTS include:

  • repetitive maneuvers
  • repeated use of vibrating hand tools
  • pregnancy, for example, because of edema or fluid retention
  • inflammatory, degenerative, and rheumatoid arthritis (RA)
  • hypothyroidism, or underactive thyroid
  • diabetes
  • physical trauma, such as dislocation or fracture of the wrist
  • lesions in the wrist
  • a cyst or tumor in the carpal tunnel
  • an overactive pituitary gland
  • any kind of swelling or inflammation around the tendons

Occupational causes

Certain occupations may put a person at a greater risk of developing CTS. According to the Canadian Centre for Occupational Health and Safety, the following occupations belong in that category:

  • farmers, specifically those milking cows
  • workers using air-powered hand tools
  • assembly-line workers handling objects on the conveyor belt
  • check-out cashiers using laser scanners
  • factory, farm, or mechanical workers who wear tight gloves
  • gardeners weeding by hand
  • locksmiths, turning keys
  • mechanics, using screwdrivers and pushing down ratchets
  • musicians using a bow for a stringed instrument
  • office workers using mouse and keyboard
  • painters who repeatedly use a spray gun
  • poultry- or meat-processing workers who are deboning and cutting
  • stablehands, painters, and carpenters who press tools into the palm

Repetitive movements from activities such as knitting can also increase the risk of CTS.

Not every person who works on a computer or milks cows for hours daily will develop CTS. A few factors that may increase the likelihood of developing it include:

  • Sex: Females are 10 times more likely to develop CTS than males.
  • Age: CTS usually develops in individuals aged 40–60 years.
  • Obesity: People with obesity are more at risk of CTS.
  • Pregnancy: CTS can develop during pregnancy and then fade after a birth.
  • Diabetes and other metabolic disorders: These conditions can affect the body’s nerves and make a person more susceptible to nerve compression.

Treatment aims to relieve symptoms and slow the progression of CTS by reducing pressure on the median nerve.

Individuals with mild symptoms may find that their condition improves without treatment within a few months, especially if they are able to reduce repetitive movements that might have caused CTS in the first place.

Self-help tips

The following may help reduce discomfort:

  • Resting the hand and wrist: The more rest the hand and wrist get, the greater the chance of relieving the symptoms.
  • Applying cold compresses: Placing an ice pack on the wrist may help during a flare-up. However, a person should not apply ice directly onto the skin.
  • Managing the triggers: If CTS stems from repetitive hand movements, a person should try to take breaks so the hand and wrist have time to rest and recover.
  • Using occupational therapy: A therapist can teach a person how to carry out repetitive tasks differently.
  • Wearing wrist splints: These keep the wrist in the same position and prevent it from bending. They can be worn during sleep, as well as during waking hours if they do not interfere with daily activities. Wrist splints are available over the counter at pharmacies. A doctor or pharmacist can advise about the best one to choose.

Medications

Nonsteroidal anti-inflammatory drugs, such as aspirin and ibuprofen, may help relieve short-term pain.

A doctor may also recommend corticosteroids to reduce inflammation. A person typically receives corticosteroids as an injection directly into the wrist, but they can also take them orally, as is the case with prednisone.

If the response is good, but symptoms return after a few months, a doctor may recommend another dose. However, continued use of corticosteroids is not advisable, as long-term side effects may occur.

Moreover, although botox injections are not an actual medication, they may provide relief from tendon tension.

Surgery

In severe cases where other treatments have not been effective, and symptoms have lasted at least 6 months, surgery may be appropriate.

Carpal tunnel surgery is currently one of the most common procedures surgeons carry out in the U.S. Often times, surgery does not require an overnight hospital stay.

There are two main types of CTS surgery: open release and endoscopic.

Open release surgery is a more traditional CTS surgery. It involves making a small incision in the wrist and cutting the carpal ligament to enlarge the carpal tunnel.

Endoscopic surgery involves making small incisions in the wrist and palm and inserting a tiny camera into the wrist. A surgeon will then look at the tendons and ligaments and cut the carpal ligament.

A person may find relief right after surgery, but it can take several months to fully recover. Grip strength may take a few months to come back as well.

Common side effects of surgery can include:

  • infections around the scar
  • nerve damage around the scar
  • pain around the scar

Individuals should contact a doctor if they experience any side effects, especially infection, after surgery.

Self-tests for CTS include noticing whether there is any pain or aches in the fingers, hand, or arm or whether grip strength seems to be weakening. However, these tests are not conclusive.

A primary care physician can usually diagnose CTS after asking about symptoms and examining the hand and wrist for signs of weakness in the muscles around the thumb. They will also assess how well the person can use the affected hand and wrist.

A number of tests can indicate whether a person is likely to have CTS:

  • Tinel’s test, or Tinel’s sign: The doctor taps the median nerve at the wrist lightly to see whether the person feels numbness or tingling in one or more fingers.
  • Phalen’s test for wrist flexion: The person presses the backs of the hands against each other so that the wrist is bent. If tingling or numbness occurs within 1 minute, there may be damage to the median nerve.
  • Nerve conduction study: Electrodes are placed on the hand and wrist. Small electric shocks are applied. The test measures how quickly the nerves transmit the impulses to the muscles.
  • Electromyography: A fine needle is inserted into the muscle. Electrical activity on a screen can reveal whether there is any median nerve damage, and if so, how severe it is.
  • Blood tests: Blood tests can detect an underlying condition that can be related to CTS, including hypothyroidism, RA, and diabetes.
  • Imaging scans: An X-ray can show whether there is a fracture or some other health issue, such as RA, present. An ultrasound scan can check the structure of the median nerve. Studies have found that MRI scans are not useful in diagnosing CTS.

Here are two exercises that may help relieve the discomfort of CTS:

1. Make a fist, with the back of the hand facing down. Slide the fingers up until they are pointing straight up toward the ceiling. Repeat 5–10 times.

2. Make a fist. Open the hand and spread out the fingers, stretching them as far as possible. Repeat 5–10 times.

It is important to note that a person suspecting they have CTS should not self-diagnose or try to treat the suspected condition on their own. Seeking guidance from a healthcare professional is the best way to get a proper diagnosis and find the most suitable treatment plan.

Measures to reduce the risk of developing CTS include:

  • not gripping too hard when performing manual tasks
  • not overbending the wrist, for example, all the way down or up
  • sleeping and working with the wrists straight
  • avoiding repeated flexing and extending of the wrists
  • maintaining correct posture to prevent putting undue strain on the wrists and hands
  • redesigning the workstation to reduce unnatural and taxing wrist positions
  • resting and taking frequent breaks when performing routine tasks, to protect against the long-term effects
  • treating any underlying conditions, for example, establishing good glucose management to help prevent the complications of diabetes

Working on a computer may have only a slight effect on the development of CTS. However, using a keyboard with an elevated and curved surface may reduce strain by helping keep the hands in a neutral position.

Some people recommend hand movement exercises, including yoga, and massages, but research has not confirmed that these are effective.

CTS is a common condition with symptoms that can start slowly. If a person does not receive treatment, over time, CTS can lead to serious pain and numbness in the fingers, hand, and arm.

Individuals can treat mild forms of CTS with home remedies, such as easing repetitive movements, using ice, and taking over-the-counter pain relievers. More severe forms of the condition may require steroid injections or even surgery.

A person who suspects they may have CTS should consult a doctor, as getting an early diagnosis and proper treatment can help bring relief sooner and avoid complications.