Carpal Tunnel Syndrome

Overview

Carpal tunnel syndrome occurs when the median nerve, which runs from the forearm through the wrist and into the palm of the hand, becomes pressed or squeezed at the wrist.

The median nerve and the tendons that bend the fingers pass through the carpal tunnel, a narrow, rigid tube of ligament and bones at the base of the hand. The median nerve provides feeling to the thumb, index, and middle finger, and part of the ring finger, but not the little finger. It also controls some small muscles at the base of the thumb.

Anyone can develop carpal tunnel syndrome, but the condition usually occurs in adults. Women are more likely than men to develop the syndrome.

Signs and Symptoms

Symptoms usually start slowly. Early symptoms include:

• Numbness or tingling in the fingers, especially the thumb and the index and middle fingers
• Weakness or tingling in the fingers
• Fingers that feel swollen and cold
• Waking up feeling the need to “shake out” the hand or wrist

Symptoms often first appear in one or both hands at night but go away during the day.

As symptoms worsen, a person may feel discomfort during the day, especially with activities that require use of the wrist and hand. These activities may include:

• Talking on the phone
• Reading a book or newspaper
• Driving

In chronic or untreated cases, the fingers can feel numb all the time. A person may also have difficulty grabbing small objects, such as buttons and zippers. The muscles at the base of the thumb may become so weak that it becomes difficult or impossible to grasp small objects.

Causes and Risk Factors

Researchers do not know the exact causes of carpal tunnel syndrome. It may result from a combination of factors that increase pressure on the median nerve and tendons in the carpal tunnel, rather than a problem with the nerve itself. Sometimes, irritated tendons can thicken or swell, which can narrow the tunnel and compress the median nerve. In many cases, no single cause can be identified.

Environmental Factors

• Trauma or injury to the wrist, such as a sprain or fracture, that causes swelling
• Mechanical problems in the wrist joint
• Repeated use of vibrating machinery

Medical Conditions

• Problems with the pituitary gland or the thyroid gland
• Rheumatoid arthritis or other autoimmune diseases
• Diabetes or other metabolic disorders that make the body’s nerves susceptible to compression
• Fluid retention during pregnancy or menopause

Other Risk Factors

• Age: Carpal tunnel syndrome usually occurs in adults
• Sex: Women are more likely than men to develop carpal tunnel syndrome

Diagnosis

Early diagnosis and treatment are important to avoid further damage to the median nerve.

Most cases of carpal tunnel syndrome can be diagnosed through a physical exam. The doctor will examine the hands, arms, shoulders, and neck to help determine if symptoms relate to daily activities or another disorder, and to rule out other causes. The wrist will be examined to see if tapping, pressing on the median nerve, or flexing the wrist causes a numbing or tingling sensation. Fingers will be tested for sensation, and muscles at the base of the hand will be tested for strength and signs of weakening.

In some cases, a doctor may order laboratory tests and X-rays to help find any fractures, arthritis, or nerve-damaging diseases such as diabetes.

In cases where carpal tunnel syndrome cannot be diagnosed through a physical exam alone, other tests may be ordered, including.

• A nerve conduction study, which measures how quickly signals travel along a nerve to see if they are slowed down at the carpal tunnel.
• Electromyography can determine the severity of muscle damage due to carpal tunnel syndrome.
• Ultrasound can be used to see if the median nerve is swollen at the carpal tunnel.

Treatment and Management

Treatments for carpal tunnel syndrome should begin as soon as possible. Underlying causes such as diabetes or arthritis should be treated first.

Nonsurgical Treatments

Nonsurgical treatments can improve carpal tunnel syndrome symptoms in the short term, but they do not treat the underlying problem with the median nerve or lead to long-term improvements. These include:

• Using a splint on the hand and wrist at night is a common initial treatment option for carpal tunnel syndrome symptoms.
• A steroid injection into the carpal tunnel can temporarily relieve carpal tunnel syndrome symptoms.

Surgical Treatements

Carpal tunnel release is one of the most common surgical procedures in the United States. It involves using a small incision and cutting a ligament to relieve pressure on the median nerve. Some people with carpal tunnel syndrome may need surgery on both wrists.

There are two methods of carpal tunnel release surgery:

• Open release surgery is the traditional procedure. A surgeon makes an incision in the wrist and cuts the carpal ligament to enlarge the carpal tunnel. The procedure is generally done under local anesthesia on an outpatient basis.
• Endoscopic surgery involves one or two small incisions in the wrist and palm. A camera attached to a tube is inserted to view the nerve, ligament, and tendons on a monitor. The surgeon then cuts the carpal ligament with a small knife inserted through the tube. This type of surgery may allow for faster recovery and less discomfort than open release surgery, but it also carries a higher risk of complications and the need for repeat surgery.

Although carpal tunnel surgery may quickly relieve symptoms, full recovery depends on the severity of carpal tunnel syndrome and can take months to years. All surgeries carry risks, including infections, nerve damage, stiffness, or pain at the scar. Surgery usually solves the issue, and it is very rare for carpal tunnel syndrome to return after surgery.

Living With Carpal Tunnel Syndrome

There are many things a person can try to help manage early carpal tunnel syndrome symptoms, including:

• Wearing a splint on the hand and wrist at night
• Using ice packs as needed
• Taking medicines as prescribed by a doctor
• Seeking medical care when needed
• Resting the hands periodically
• Minimizing repetitive movements
• Taking short breaks when doing repetitive tasks with the hands
• Using ergonomically designed tools and furniture when possible

Find Clinical Trials

Clinical trials uncover better ways to prevent, diagnose, treat, and understand diseases and conditions. To ensure results apply to everyone, volunteers of all ages, sexes, and backgrounds, including both healthy individuals and those with specific medical conditions, are needed. Find clinical trials on Carpal Tunnel.

Find Treatment

A person with carpal tunnel syndrome can be initially seen and treated by:

• Neurologists, who diagnose and treat nerve disorders
• Neurosurgeons, who specialize in the diagnosis and surgical treatment of peripheral nerve disorders
• Orthopedic surgeons, who specialize in diagnosing and treating injuries to bones, joints, ligaments, tendons, muscles, and nerves
• Primary healthcare providers, including family doctors, internists, and rheumatologists who treat problems as they arise and coordinate care between specialized healthcare providers

A person with carpal tunnel syndrome may also see:

• Occupational and physical therapists, who teach ways to strengthen muscles and joints, minimize pain, and perform activities of daily living
• Pain management specialists, who are physicians trained in the evaluation and treatment of pain
• Physiatrists, who are doctors specializing in nonsurgical management of musculoskeletal conditions and can develop a plan of care, including rehabilitation

Community Support

The following organizations provide information and resources related to carpal tunnel syndrome:

• U.S. Food and Drug Administration
• Search FDA-approved drug products at Drugs@FDA
• Centers for Disease Control and Prevention
• Occupational Safety and Health Administration
• American Academy of Orthopaedic Surgeons
• American College of Rheumatology
• American Physical Therapy Association
• Arthritis Foundation
• Foundation for Peripheral Neuropathy
• American Society for Surgery of the Hand

Note: This resource list is for informational purposes only. It is not comprehensive, and an organization’s inclusion does not constitute an endorsement by NIH.  

Research Information

The National Institutes of Health (NIH) is the largest public funder of biomedical research in the world. NIH invests most of its budget in medical research seeking to enhance life and to reduce illness and disability. NIH-funded research has led to breakthroughs and new treatments helping people live longer, healthier lives, and building the research foundation that drives discovery.  

Scientists supported by NIH are working to better understand, treat, and prevent carpal tunnel syndrome. Example ongoing studies include:

• Using advanced brain imaging in people with carpal tunnel syndrome
• Studying the role of cellular senescence in carpal tunnel syndrome, which is the process by which cells age and stop dividing
• Building a tool to help people with carpal tunnel syndrome evaluate treatment options in consultation with their doctor
• Using noninvasive brain stimulation along with physical therapy to treat chronic pain in people with carpal tunnel syndrome
• Exploring new ways to understand the mechanisms involved in grasp and other forces that affect the hand, which may lead to the development of better assistive and rehabilitation devices

Find NIH-funded research projects using NIH RePORTER, a searchable database of current and past research projects supported by NIH and other federal agencies.