Carpal tunnel syndrome


What is carpal tunnel syndrome?

Carpal tunnel syndrome (CTS) is the most common nerve entrapment disorder. It involves narrowing of a passage in the wrist called the carpal tunnel. This constricted tunnel presses on or pinches the median nerve and causes chronic pain in the wrist and hand.

The median nerve controls sensation in the palm side of the thumb, index finger, middle finger and part of the ring finger, as well as the impulses to some small muscles in the hand that allow the fingers and thumb to move.

The carpal tunnel receives its name from the eight bones in the wrist, called carpals, that form a structure resembling a tunnel or canal. The carpal ligament wraps around this passage. In addition to accommodating the median nerve, the carpal tunnel also contains blood vessels, connective tissue and flexor tendons, which control flexion (bending) of the fingers.

Carpal tunnel syndrome (CTS) is the most common nerve entrapment disorder. It involves narrowing of a passage in the wrist called the carpal tunnel. This constricted tunnel presses on or pinches the median nerve and causes chronic pain in the wrist and hand.

The median nerve controls sensation in the palm side of the thumb, index finger, middle finger and part of the ring finger, as well as the impulses to some small muscles in the hand that allow the fingers and thumb to move.

The carpal tunnel receives its name from the eight bones in the wrist, called carpals, that form a structure resembling a tunnel or canal. The carpal ligament wraps around this passage. In addition to accommodating the median nerve, the carpal tunnel also contains blood vessels, connective tissue and flexor tendons, which control flexion (bending) of the fingers.

Risk factors and potential causes of CTS

Carpal tunnel syndrome (CTS) is a progressively painful condition. It often results from a combination of factors that increase pressure on the median nerve (which help controls sensations and movement in the hand and fingers) and tendons in the carpal tunnel (tunnel-like structure of bones and ligaments in the wrist), rather than a problem with the nerve itself.

In most cases, the exact cause of CTS is unknown. However, several risk factors have been associated with the disorder, including:


Recent studies have strengthened scientists' belief that genetic predisposition plays a role in CTS.

Injury or trauma

A fracture or sprain of the wrist can cause swelling and pressure on the median nerve, increasing the risk of CTS. Forceful and stressful movements of the hand and wrist, such as those associated with the use of heavy machinery or power tools, can also cause trauma.

Repetitive hand, wrist or finger movement

People who repeatedly perform the same hand-intensive movements for a prolonged period might be more likely to develop CTS. Such movements may involve a combination of awkward, repetitive wrist or finger motions, forceful pinching or gripping and working with vibrating tools.

However, the association between activities such as typing and CTS remains unclear. Some research suggests there may be a link, but other studies have found no higher prevalence of CTS in some professions that strain the hands, such as court reporting and construction work.

Improper posture and ergonomics

Poor positioning of the wrist or hands during repetitive activities may increase the risk of CTS.

Sex and age

Women are three times more likely than men to develop CTS. In women, the incidence peaks after menopause. For men, the risk increases during middle age.


The buildup of fluid (edema) in the carpal tunnel that occurs during pregnancy may put pregnant women at risk for developing CTS. However, in most cases, CTS resolves after childbirth.


Although the link between the loss of ovarian function and CTS is unclear, studies suggest that hormonal changes occurring during menopause may put women at risk for CTS. In addition, sometimes the wrist structures of postmenopausal women become enlarged and can press on the median nerve and induce symptoms of CTS.


Some women who undergo this procedure experience lymphedema (excessive buildup of fluids in the lymph nodes and vessels). In mastectomy patients, lymphedema is painful and may cause the arm to swell. In rare cases, some of these patients may develop CTS because of pressure on the median nerve from the swelling.

Size of the carpal tunnel

Studies suggest that the cross-sectional area of the carpal tunnel may be narrower in CTS patients.

Research suggests an increased risk of CTS in individuals with a body mass index (BMI) greater than 29.

Kidney dialysis

CTS is common in patients with kidney disease who undergo prolonged dialysis treatment. CTS is present in as many as 30 percent of patients who undergo dialysis for more than nine years.

Growth hormone treatments

Some endocrine disorders are treatment with growth hormone, which is also sometimes promoted as an anti-aging treatment despite negative side effects including joint swelling, CTS and increased risk of diabetes.

A higher incidence of CTS has been noted in patients who have one or more of a wide range of diseases, including:

  • Rheumatoid arthritis (RA). A debilitating inflammatory disease that causes pain, swelling, stiffness and loss of function in the joints. RA patients may be at higher risk for developing CTS. However, in many cases, the symptoms of median nerve compression resolve as the rheumatoid arthritis is treated.
  • Gout. A form of arthritis caused by the buildup of uric acid crystals in the joints, causing inflammation, swelling and pain. The joint swelling in gout patients may predispose them to CTS.
  • Osteoarthritis. The most common form of arthritis, which can affect the wrist.
  • Lupus. An inflammatory autoimmune disorder that can affect the skin, joints and internal organs. The joint inflammation associated with lupus may put patients at an increased risk for developing CTS.
  • Acromegaly. A rare endocrine disorder in which the pituitary gland produces excess growth hormone. Patients experience overgrowth of bone and cartilage, which can lead to CTS. In most cases, treatment for acromegaly usually leads to rapid resolution of CTS.
  • Diabetes. Diabetic patients may be at higher risk for CTS because diabetes makes the nerves more susceptible to compression and impingement.
  • Hypothyroidism. An underactive thyroid gland, often caused by thyroiditis (inflammation of the gland). CTS may be associated with this thyroid disorder because hypothyroid patients tend to retain fluid in their connective tissues due to an accumulation of mucopolysaccharides, substances that accumulate abnormally in hypothyroidism. This exacerbates the swelling and worsens the compression of the median nerve. Less commonly, CTS may develop in patients with hyperthyroidism (overactive thyroid).
  • Sarcoidosis. A disease of unknown cause that is characterized by widespread lesions in the body.
  • Amyloidosis. A condition in which proteins are deposited in tissues and organs.
  • Fibromyalgia. A chronic disorder that causes muscle pain and fatigue. Studies suggest that CTS can occur, and is frequently unrecognized, in fibromyalgia patients. However, the overall incidence of CTS in fibromyalgia patients might not be different from that of the general population.

CTS is also associated with the type of trauma that causes hand-arm vibration syndrome (HAVS) and can coexist with the disorder. HAVS results from prolonged exposure to vibration, specifically to the hands and forearms while using certain types of vibrating tools (e.g., jackhammers, power chain saws). The symptoms of HAVS are similar to CTS and include numbness, tingling and loss of nerve sensitivity.

Signs and symptoms of CTS

In most cases, carpal tunnel syndrome (CTS) begins slowly, with a slight aching of the wrist that extends to the hand or forearm. This pain initially may be felt only at night. One or both wrists may be involved. Other common signs and symptoms include:

  • Tingling and/or numbness of the fingers and/or hand. The thumb, index, middle and ring fingers are affected, but the median nerve does not serve the pinky. Sensations of tingling and numbness are more apparent while engaging in certain activities, such as driving a vehicle or holding a phone or other object. To relieve this symptom, many people shake out their hands.
  • Radiating wrist pain. Pain that radiates or extends from the wrist up the arm to the shoulder or down into the palm or fingers is a symptom of CTS. This is especially common after forceful or repetitive use. In most instances, this occurs on the palm side of the forearm.
  • Weakness of the hands or a tendency to drop objects, even if they are not heavy, in cases of advanced CTS.
  • Permanent loss of feeling in some fingers. This can occur if CTS is advanced.
People with CTS usually experience an increase in symptoms at night and when they awaken each morning. This may be due to their daily activities, which can exacerbate symptoms (e.g., repetitive hand motions, use of power tools) and their sleeping habits (if they sleep with their wrist bent), which can result in numbness and/or pain upon awakening.

In addition, research indicates that CTS patients who smoke cigarettes usually experience more severe symptoms and tend to recover more slowly than nonsmokers.

Left untreated, symptoms can become progressively worse and may result in permanent nerve damage and the loss of hand and wrist strength due to muscle wasting (atrophy). Eventually, CTS patients may have trouble differentiating between hot and cold by touch.

Individuals who experience any persistent symptoms, especially if they interfere with sleep or other daily activities, are advised to contact their physician for an evaluation. With proper treatment, most CTS patients experience relief from the pain and numbness and regain normal use of their wrists and hands.

Diagnosis methods for CTS

To diagnose carpal tunnel syndrome (CTS), the physician will review the patient’s medical history and perform a physical examination. In learning about the medical history, the physician will ask about any conditions that may be associated with CTS, such as pregnancy, diabetes, hypothyroidism or rheumatoid arthritis.

The physician will also inquire about any recent accidents or injuries involving the wrist, hand or arm that may be causing CTS. In addition, the physician will ask about any activities the patient engages in that might contribute to CTS, such as typing, playing a musical instrument or using power tools.

During the physical exam, the physician will test the feeling in the fingers and the strength of the muscles in the hand because these can be affected by CTS. The physician will also examine the neck, shoulder and elbow also to determine the possible level of nerve entrapment. In many patients, applied pressure on the median nerve in the wrist – by either bending the wrist (Phalen's sign), tapping on the nerve (Tinel's sign) or just pressing on it – can bring about the symptoms.

To confirm a diagnosis of CTS, a physician may order further tests, which may include:

Blood tests

Laboratory analysis of blood samples to determine if any underlying condition is contributing to the symptoms. In some cases, treatment of the underlying disorder alleviates CTS symptoms. In the case of pregnancy, CTS usually disappears after childbirth.


A noninvasive imaging test that uses sound waves to produce images of the shape and outline of various tissues and organs in the body. Ultrasound can show impaired movement of the median nerve.


Type of radiography using low doses of radiation to produce images of body parts on film or fluorescent screens. However, x-rays are useful only when injuries such as a fracture in the hand or wrist are present.

MRI (magnetic resonance imaging)

A noninvasive or minimally invasive imaging test that uses powerful magnets to produce images of organs and vessels in the body on a computer screen and film. An MRI can allow the physician to view the anatomy of the wrist but by itself is not very useful in diagnosing CTS.

Electrodiagnostic tests

These tests may be useful in localizing impingement of the median nerve:

  • Nerve conduction study. Two electrodes are taped to the hand and wrists. A small shock is passed through the median nerve to see if electrical impulses are slowed in the carpal tunnel. However, this type of test is not always definitive because a false-negative result can occur in up to 10 percent of patients.
  • Electromyography. A physician inserts a thin-needle electrode into the muscle being studied. An instrument records the electrical activity in the muscle at rest and as the patient contracts or moves it. The electrical activity is viewed on a screen and allows the physician to determine the severity of damage to the median nerve.
  • Electromyography can be painful and is usually recommended in certain instances (e.g. conservative therapy was unsuccessful, unclear diagnosis, evidence of motor dysfunction). However, this test is one of the best diagnostic tests and is positive in more than 85 percent of the patients with the disease. In cases where surgery is needed, many surgeons may for legal reasons require this type of electrodiagnostic proof of nerve compression before performing surgery.

Researchers in 2007 reported finding biomarkers (chemicals in the body) that may be an early signal of CTS. The discovery could one day lead to a test that allows improved diagnosis and prevention of the condition.

Treatment options for CTS

Left untreated, carpal tunnel syndrome (CTS) can ultimately lead to permanent atrophy (wasting) of the hand muscles. Treatment for CTS with a physician specializing in the disorder should begin as soon as possible to avoid permanent damage to the median nerve, one of the nerves that control hand and finger movement and sensation.

Physicians will treat any underlying causes of CTS first (e.g., diabetes, hypothyroidism, rheumatoid arthritis). In some cases, symptoms (pain, tingling and numbness in the arm, hand and/or wrist) improve with treatment of the underlying cause.

Initial treatment of CTS generally involves resting the affected hand and wrist for up to two weeks, avoiding activities that might exacerbate symptoms (e.g. knitting, use of power tools) and applying cool packs (cryotherapy) to reduce swelling.

For those whose jobs involve extensive hand movement, a physician may recommend the use of an elastic glove. Also, a physician may recommend strength and stretching exercises to maintain wrist strength and mobilize nerves and tendons.

In addition, studies sponsored by the National Institutes of Health indicate that yoga and acupuncture may also help relieve CTS pain.

If these techniques do not work, a physician may recommend:

Wrist splinting

In this type of conservative therapy, a patient wears a splint that holds the wrist in a slightly extended position (bent upward) to help relieve symptoms of tingling and numbness. Sometimes splints are worn only at night, but full-time use may be recommended to maximize benefits. Splinting is more likely to be effective if a patient has only mild to moderate symptoms for less than a year. Splints are available premade, or they can be individually designed by an occupational therapist or a physical therapist.

In cases where inflammation is present, the short-term use of nonsteroidal anti-inflammatory drugs (NSAIDs) or oral corticosteroids may help control pain caused by CTS. However, if no inflammatory condition is present, these medications are unlikely to help relieve symptoms.

Injection therapy

A physician can inject the carpal tunnel with medication such as a corticosteroid or local anesthetic to relieve the pain. However, this procedure can be risky and should be performed only by physicians with specific training in carpal tunnel injection. If injected incorrectly, it can result in nerve deterioration and, in worst cases, permanent deformity of the hand.

Surgery may be recommended for CTS patients whose symptoms are severe or after other noninvasive treatments have failed to show improvement for at least six months. Carpal tunnel release is one of the most common surgical procedures in the United States. There are three types of carpal tunnel release procedures, and all involve severing the band of tissue around the wrist to reduce the pressure on the median nerve:

Open release surgery

The traditional procedure to correct CTS, it consists of making an incision (no larger than 2 inches) in the wrist and then cutting the carpal ligament to enlarge the carpal tunnel and remove pressure on the median nerve.

Endoscopic surgery (arthroscopy)

This type of surgery is performed using an endoscope (thin tube attached to a tiny television camera) which allows the surgeon to see inside the carpal tunnel and perform the surgery through small incisions in the hand or wrist. This procedure is less traumatic, and the patient may recover faster.

Small palmar incision

A physician makes a small incision in the palm of the hand over the carpal tunnel and releases the nerve. With this procedure, there is less risk of injury to vital structures and the scar is smaller so the patient experiences less pain during recovery.

After carpal tunnel release surgery, pain, tingling and numbness typically improve within six weeks. Weakness and functionality improve more gradually. Grip and pinch strength may worsen at first, then return to preoperative levels in about three months, and improve significantly by two years. Studies indicate that the majority of CTS patients who undergo surgery are very satisfied with the results.

To promote recovery after surgery, physicians may recommend that patients avoid alcohol, tobacco and exposure to any type of repetitive, forceful activities involving the use of the hand or fingers. Studies indicate that CTS patients who smoke take longer to recover from carpal tunnel release.

Rarely, there may be complications after carpal tunnel release surgery. For example, some patients may experience infection, nerve damage, stiffness and pain at the scar. In a few cases, the wrist may lose strength because the carpal ligament is cut. In such cases, physicians may recommend occupational therapy or physical therapy, preferably from a certified hand therapist (CHT), to restore wrist function.

After recovery from surgery, some patients may need to adjust their job duties or, if necessary, change jobs.

After treatment, recurrence of CTS is rare, and most patients recover completely, according to the National Institutes of Health. In addition, most CTS patients recover with conservative (noninvasive) treatment, and less than a third of patients require surgery.

Prevention methods for CTS

Use of proper body mechanics, posture and ergonomics can reduce the risk of carpal tunnel syndrome (CTS). People can take several precautions to protect their hands, including:

  • Reducing force and relaxing the grip. Most people use more force than necessary to grasp objects or perform tasks involving the hands.
  • Taking frequent breaks. Individuals may benefit from taking breaks every 15 to 20 minutes and gently stretching and bending the hands and wrists. Whenever possible, they should alternate tasks. If using vibrating tools or machinery, which requires a great amount of force, taking breaks is very important. In addition, it is recommended that workers who perform such hand-intensive tasks stretch at the start of work.
  • Using proper form and posture. Avoid bending the wrist all the way down or up. A relaxed midpoint position is best. If using a computer, make sure the keyboard is at a height that allows the wrist to rest comfortably without having to bend at a sharp angle. It also helps to keep the elbows close to the sides when typing to reduce the strain on the forearm. In addition, incorrect posture can cause the shoulders to roll forward. When the shoulders are stooped forward, the neck and shoulder muscles are shortened, which compresses the nerves in the neck – all of which can affect the wrists, hands and fingers.
  • Keeping hands warm. A person is more likely to develop hand pain and stiffness if working in a cold environment. In cases where this cannot be avoided, use fingerless gloves that keep the hands and wrists warm.
In addition, as with many disorders, a good line of defense against CTS involves maintaining a healthy weight, not smoking cigarettes (which may aggravate the condition) and exercising to maintain strength and flexibility. People with chronic illness that may result in CTS (e.g., diabetes, hypothyroidism) should seek proper medical treatment to help manage their condition.

Questions for your doctor regarding CTS

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about carpal tunnel syndrome (CTS):

  • Am I at high risk of developing carpal tunnel syndrome?
  • What could cause me to get CTS?
  • Could my wrist pain, numbness and tingling be due to CTS?
  • What other symptoms of CTS should I watch for?
  • What diagnostic tests might I need to undergo?
  • What do my test results show?
  • How will my condition likely progress?
  • Can I manage my CTS symptoms at home?
  • Should I do certain exercises or avoid certain movements?
  • Should I see a hand therapist? Do you recommend a particular therapist or facility?
  • What is next if splinting or other conservative treatments do not help me? Will I need surgical carpal tunnel release?
  • How can I prevent CTS?
  • Does using a computer for long periods put me at risk for CTS?

Additional Information


What might complicate it?

Complications following the operation are rare. The scar may be sore for some time and, if the condition had existed for some time, it may take some weeks or months for the nerve to recover and for the numbness to disappear. In some cases the symptoms may never fully disappear.

Notify your physician if

  • You or a family member has symptoms of carpal tunnel syndrome.
  • Symptoms of carpal tunnel syndrome don't lessen in 2 weeks after treatment.