What is carpal tunnel syndrome?
What are the symptoms of carpal tunnel syndrome?
What are the causes of carpal tunnel syndrome?
Who is at risk of developing carpal tunnel syndrome?
How is carpal tunnel syndrome diagnosed?
How is carpal tunnel syndrome treated?
How can carpal tunnel syndrome be prevented?
What research is being done?
Where can I get more information?
Carpal tunnel syndrome (CTS) occurs when the median nerve, which runs from the forearm into the palm of the hand, becomes pressed or squeezed at the wrist. The carpal tunnel—a narrow, rigid passageway of ligament and bones at the base of the hand—houses the median nerve and the tendons that bend the fingers. The median nerve provides feeling to the palm side of the thumb and to the index, middle, and part of the ring fingers (although not the little finger). It also controls some small muscles at the base of the thumb.
Sometimes, thickening from the lining of irritated tendons or other swelling narrows the tunnel and causes the median nerve to be compressed. The result may be numbness, weakness, or sometimes pain in the hand and wrist, or occasionally in the forearm and arm. CTS is the most common and widely known of the entrapment neuropathies, in which one of the body’s peripheral nerves is pressed upon.
Symptoms usually start gradually, with frequent burning, tingling, or itching numbness in the palm of the hand and the fingers, especially the thumb and the index and middle fingers. Some carpal tunnel sufferers say their fingers feel useless and swollen, even though little or no swelling is apparent. The symptoms often first appear in one or both hands during the night, since many people sleep with flexed wrists. A person with carpal tunnel syndrome may wake up feeling the need to "shake out" the hand or wrist. As symptoms worsen, people might feel tingling during the day. Decreased grip strength may make it difficult to form a fist, grasp small objects, or perform other manual tasks. In chronic and/or untreated cases, the muscles at the base of the thumb may waste away. Some people are unable to tell between hot and cold by touch.
Carpal tunnel syndrome is often the result of a combination of factors that reduce the available space for the median nerve within the carpal tunnel, rather than a problem with the nerve itself. Contributing factors include trauma or injury to the wrist that cause swelling, such as sprain or fracture; an overactive pituitary gland; an underactive thyroid gland; and rheumatoid arthritis. Mechanical problems in the wrist joint, work stress, repeated use of vibrating hand tools, fluid retention during pregnancy or menopause, or the development of a cyst or tumor in the canal also may contribute to the compression. Often, no single cause can be identified.
Women are three times more likely than men to develop carpal tunnel syndrome, perhaps because the carpal tunnel itself may be smaller in women than in men. The dominant hand is usually affected first and produces the most severe pain. Persons with diabetes or other metabolic disorders that directly affect the body's nerves and make them more susceptible to compression are also at high risk. Carpal tunnel syndrome usually occurs only in adults.
The risk of developing carpal tunnel syndrome is not confined to people in a single industry or job, but is especially common in those performing assembly line work - manufacturing, sewing, finishing, cleaning, and meat, poultry, or fish packing. In fact, carpal tunnel syndrome is three times more common among assemblers than among data-entry personnel.
Early diagnosis and treatment are important to avoid permanent damage to the median nerve.
Treatments for carpal tunnel syndrome should begin as early as possible, under a doctor's direction. Underlying causes such as diabetes or arthritis should be treated first.
Carpal tunnel release is one of the most common surgical procedures in the United States. Generally, surgery involves severing a ligament around the wrist to reduce pressure on the median nerve. Surgery is usually done under local or regional anesthesia (involving some sedation) and does not require an overnight hospital stay. Many people require surgery on both hands. While all carpal tunnel surgery involves cutting the ligament to relieve the pressure on the nerve, there are two different methods used by surgeons to accomplish this.
Following surgery, the ligaments usually grow back together and allow more space than before. Although symptoms may be relieved immediately after surgery, full recovery from carpal tunnel surgery can take months. Almost always there is a decrease in grip strength, which improves over time. Some individuals may develop infections, nerve damage, stiffness, and pain at the scar. Most people need to modify work activity for several weeks following surgery, and some people may need to adjust job duties or even change jobs after recovery from surgery.
Although recurrence of carpal tunnel syndrome following treatment is rare, fewer than half of individuals report their hand(s) feeling completely normal following surgery. Some residual numbness or weakness is common.
At the workplace, workers can do on-the-job conditioning, perform stretching exercises, take frequent rest breaks, and ensure correct posture and wrist position. Wearing fingerless gloves can help keep hands warm and flexible. Workstations, tools and tool handles, and tasks can be redesigned to enable the worker's wrist to maintain a natural position during work. Jobs can be rotated among workers. Employers can develop programs in ergonomics, the process of adapting workplace conditions and job demands to the capabilities of workers. However, research has not conclusively shown that these workplace changes prevent the occurrence of carpal tunnel syndrome.
The mission of the National Institute of Neurological Disorders and Stroke (NINDS) is to seek fundamental knowledge of the brain and nervous system and to use that knowledge to reduce the burden of neurological disease. The NINDS is a component of the National Institutes of Health (NIH), the leading supporter of biomedical research in the world.
Scientists supported by the NINDS are studying the factors that lead to progressive nerve injury and how damage to nerves is related to symptoms of pain, numbness, and loss of function. Researchers also are examining biomechanical stresses that contribute to the nerve injury responsible for symptoms of carpal tunnel syndrome in order to better understand, treat, and prevent this ailment. By quantifying the distinct biomechanical pressures from fluid and anatomical structures, researchers are finding ways to limit or prevent CTS in the workplace and decrease other costly and disabling occupational illnesses.
Scientists funded through NIH's National Center for Complementary and Integrative Health are investigating the effects of acupuncture on pain, loss of median nerve function, and changes in the brain associated with CTS. In addition, a randomized clinical trial designed to evaluate the effectiveness of osteopathic manipulative treatment in conjunction with standard medical care is underway. Evaluations of these and other therapies will help to tailor individual treatment programs.
Another NIH component, the National Institute of Arthritis and Musculoskeletal and Skin Disorders (NIAMS), supports research on tissue damage associated with repetitive motion disorders, including CTS. As part of this research, scientists have developed animal models that are helping to understand and characterize connective tissue in hopes of reducing tissue buildup and identifying new treatments.
More information about carpal tunnel syndrome research supported by NINDS and other NIH Institutes and Centers can be found using NIH RePORTER (projectreporter.nih.gov), a searchable database of current and past research projects supported by NIH and other Federal agencies. RePORTER also includes links to publications and resources from these projects.
For more information on neurological disorders or research programs funded by the National Institute of Neurological Disorders and Stroke, contact the Institute's Brain Resources and Information Network (BRAIN) at:
P.O. Box 5801
Bethesda, MD 20824
Information also is available from the following organizations:
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
National Institutes of Health, DHHS
31 Center Dr., Rm. 4C02 MSC 2350
Bethesda, MD 20892-2350
Centers for Disease Control and Prevention (CDC)
U.S. Department of Health and Human Services
1600 Clifton Road
Atlanta, GA 30333
404-639-3311 or 404-639-3543
Occupational Safety & Health Administration
U.S. Department of Labor
200 Constitution Avenue, N.W.
Washington, DC 20210
U.S. National Library of Medicine
National Institutes of Health/DHHS
8600 Rockville Pike
Bethesda, MD 20894
"Carpal Tunnel Syndrome Fact Sheet", NINDS, Publication date January 2017.
NIH Publication No. 17-4898
Office of Communications and Public Liaison
National Institute of Neurological Disorders and Stroke
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NINDS health-related material is provided for information purposes only and does not necessarily represent endorsement by or an official position of the National Institute of Neurological Disorders and Stroke or any other Federal agency. Advice on the treatment or care of an individual patient should be obtained through consultation with a physician who has examined that patient or is familiar with that patient's medical history.
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