Carpal Tunnel Syndrome

Carpal tunnel syndrome is one of the most common hand conditions, affecting approximately 3 out of every 1,000 people in the United States each year. It occurs when pressure on a key nerve in the wrist causes pain, numbness, and tingling in the hand and fingers.

Table of contents

• What Is Carpal Tunnel Syndrome?
• Signs and Symptoms
• Causes and Risk Factors
• How It Is Diagnosed
• Treatment Options
• Living With Carpal Tunnel Syndrome

What Is Carpal Tunnel Syndrome?

The carpal tunnel is a narrow passageway in your wrist, about an inch wide. The floor and sides of this tunnel are formed by small wrist bones called carpal bones, and the roof is a strong band of tissue called the transverse carpal ligament^[4]. This tunnel is like a road through a mountainside, but instead of making room for cars, it creates a pathway in your bones that allows important structures to pass through to your hand^[2].

Inside the carpal tunnel, a major nerve called the median nerve travels from your forearm into your palm. This nerve is responsible for providing feeling to your thumb, index finger, middle finger, and half of your ring finger. It also controls the muscles around the base of your thumb that allow you to grip objects^[1]. Nine tendons that help you bend your fingers and thumb also pass through this tunnel alongside the nerve^[4].

Carpal tunnel syndrome happens when something irritates or puts extra pressure on the median nerve as it passes through the carpal tunnel. Because the boundaries of the tunnel are very rigid, the carpal tunnel has little capacity to stretch or increase in size^[4]. When tissues inside the tunnel become swollen or damaged, they can press on the nerve, causing it to send incorrect or extra signals to your hand and wrist^[2].

This condition is extremely common and is the most prevalent type of focal mononeuropathy (a condition affecting a single nerve), making up 90% of all nerve compression cases^[3]. It affects approximately 3 percent of adults in the United States^[12].

Signs and Symptoms

Carpal tunnel syndrome usually develops slowly over time. You might only notice minor symptoms at first, but these tend to get worse as the condition progresses^[2]. The typical first signs include pain, numbness, and tingling that affect the first three fingers and the outer half of the fourth finger^[3].

People with carpal tunnel syndrome commonly experience tingling and numbness in their fingers or hand. These sensations typically occur in the thumb, index finger, middle finger, and ring finger, but not in the little finger^[1]. Many people describe the feeling as similar to an electric shock or like their fingers “fell asleep”^[2].

Pain is another frequent symptom. This pain usually feels like it’s coming from inside the hand or wrist, rather than from the skin surface. It may feel like a sharp, burning stab or a constant ache^[2]. In some cases, the pain can radiate from the wrist up into the forearm or even extend beyond the elbow into the shoulder^[3].

Weakness in the hand is also common. People with carpal tunnel syndrome may drop objects more frequently or have difficulty gripping items like a phone, steering wheel, or pen^[2]. This weakness may be due to numbness or to actual weakness of the thumb’s muscles, which are also controlled by the median nerve^[1]. Your hands and fingers may feel clumsy or less able to perform precise movements, such as buttoning a shirt or inserting a key into a lock^[2].

Symptoms often first appear at night. Pain or tingling may wake you from sleep, and many people “shake out” their hands like they’re flinging water off them to try to relieve their symptoms^[1]. These nighttime symptoms commonly occur while lying down and tend to improve during the daytime^[3].

As the condition advances, symptoms may begin to occur during the day, especially when performing repetitive activities such as holding a phone or newspaper, gripping a steering wheel, typing, drawing, or playing video games^[1][3]. In advanced cases, symptoms may become persistent or constant^[3]. If left untreated for too long, carpal tunnel syndrome can lead to permanent damage, including loss of feeling in the fingers and atrophy (wasting away) of the thumb muscles^[1][3].

Causes and Risk Factors

The main cause of carpal tunnel syndrome is elevated pressure within the carpal tunnel^[3]. This extra pressure on the median nerve can result from various factors that cause swelling or irritation in the wrist. Anything that makes tissues inside the tunnel swell or become damaged can press on other structures around it, including the median nerve^[2].

In many cases, the exact cause is unknown. However, the condition often results from a combination of things that affect the structures in the wrist^[6]. Common causes include repetitive strain injuries, arthritis, sprains, wrist fractures (broken wrist bones), and fluid-filled sacs called ganglion cysts^[2].

Certain activities and occupations can increase the risk of developing carpal tunnel syndrome. Jobs that involve frequent exposure to vibrating equipment or repetitive wrist and hand movements significantly elevate the risk^[3]. Examples include assembly line work, carpentry, using tools that vibrate, knitting, gardening, and sports such as golf, bicycling, gymnastics, or tennis^[5][6].

Despite widespread belief, heavy usage of computer keyboards has never been proven to be a direct cause of carpal tunnel syndrome^[5]. While long-term computer use can cause wrist pain, especially if the keyboard or mouse is incorrectly positioned, the pain associated with computer use is not necessarily carpal tunnel syndrome itself^[5]. However, wrist position—whether bent forward or backward—can increase pressure on the median nerve and either cause symptoms or make them worse^[5].

Several health conditions can contribute to the development of carpal tunnel syndrome. These include diabetes, rheumatoid arthritis, hypothyroidism (an underactive thyroid gland), and other conditions that can affect nerves, joints, or other parts of the wrist^[3][5][6]. Changes in certain hormones may cause swelling from extra fluid in the body, which can lead to carpal tunnel syndrome. This can occur during pregnancy and menopause^[6].

Certain factors make some people more likely to develop carpal tunnel syndrome. Women are three times more likely to have the condition than men^[2][6]. The condition is more common in people between 30 and 60 years old^[5]. Other risk factors include obesity, genetic predisposition, having a close relative who has had carpal tunnel syndrome, problems with the way the wrist is formed, injury to the wrist that causes swelling, and having had a previous wrist injury^[3][6].

How It Is Diagnosed

To diagnose carpal tunnel syndrome, your healthcare provider will begin by asking about your medical history, family health history, and the pattern of your symptoms^[6][9]. The pattern of symptoms is important in making a diagnosis. For example, carpal tunnel syndrome symptoms usually occur while holding a phone or newspaper or gripping a steering wheel, and they tend to occur at night or may wake you from sleep^[9].

A physical examination is an important part of the diagnostic process. Your provider will test the feeling in your fingers and the strength of the muscles in your hand^[9]. Two main clinical tests are used to check for carpal tunnel syndrome: Phalen’s maneuver and Tinel’s sign. Phalen’s maneuver is positive when flexing the wrist to 90 degrees for one minute triggers symptoms in the median nerve distribution^[12]. Tinel’s sign is positive when tapping over the carpal tunnel brings on symptoms in the fingers and hand^[12]. Bending the wrist, tapping on the nerve, or simply pressing on the nerve can trigger symptoms in many people^[9].

Several tests may be ordered to confirm the diagnosis and assess the severity of the condition. An X-ray of the affected wrist may be taken to rule out other causes of wrist pain, such as arthritis or a fracture. However, X-rays are not helpful in actually diagnosing carpal tunnel syndrome^[9].

An ultrasound of the wrist can provide a picture of the tendons and nerves, which helps show whether the nerve is being compressed^[9]. Electromyography (EMG) is a test that measures the tiny electrical signals produced in muscles. During this test, a thin needle is inserted into specific muscles to evaluate their electrical activity. This test can identify damage to the muscles controlled by the median nerve and may rule out other conditions^[9].

A nerve conduction study is another electrical test used to confirm the diagnosis. In this test, two small devices are taped to the skin, and a small shock is passed through the median nerve to see how quickly it transmits signals^[9]. These electrical tests help determine the severity of nerve compression and guide treatment decisions.

Treatment Options

The sooner treatment begins, the better the chances of stopping symptoms and preventing long-term damage to the nerve^[6]. Treatment for carpal tunnel syndrome depends on how serious the condition is, whether there is any nerve damage, and whether previous treatments have helped^[13].

For people with mild symptoms, home treatment for one to two weeks is likely to relieve symptoms^[13]. Simple measures include stopping activities that cause numbness and pain, resting the wrist longer between activities, and icing the wrist for 10 to 15 minutes once or twice an hour^[13].

Wearing a wrist splint is one of the most reliable ways to stabilize the wrist and ease carpal tunnel pain^[21]. The splint takes pressure off the median nerve by keeping the wrist in a neutral position^[1]. When selecting a splint, it’s best to choose a structured, firm option that will hold the wrist still, rather than a flexible one made of stretchy material^[21].

Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen can help relieve pain and reduce swelling^[1][13]. However, a systematic review found that NSAIDs are no more effective than placebo in relieving the symptoms of carpal tunnel syndrome over the long term^[10].

Physical therapy or occupational therapy may be recommended. This can include ultrasound treatments, stretching exercises, and range-of-motion exercises^[13]. Some people find it helpful to do wrist exercises, such as making a fist and then slowly straightening and spreading the fingers, or gently bending the hand downward and holding the stretch^[21].

For more persistent symptoms, medicines may be prescribed. Orally administered corticosteroids such as prednisone can be effective for short-term management (two to four weeks)^[10][12]. Local corticosteroid injections into the carpal tunnel may improve symptoms for a longer period than oral medications^[10][12].

When symptoms are severe, do not respond to conservative measures, or when there is nerve damage or risk of nerve damage, surgery may be necessary^[1][13]. The surgical procedure for carpal tunnel syndrome is called carpal tunnel release. It involves cutting the ligament that is pressing on the median nerve to relieve pressure^[7]. Surgery may involve an open incision in the palm of the hand over the carpal tunnel, or minimally invasive surgery using small instruments inserted through one or two small incisions. Under local anesthesia, the minimally invasive procedure may be performed in as little as 10 minutes^[7]. Carpal tunnel release surgery has a high success rate^[21].

A recent study demonstrated that a minimally invasive treatment provides complete and long-term relief without the use of corticosteroids. This 15-minute treatment involves injecting saline around the nerve to separate it from the surrounding tissue, effectively treating nerve compression without surgery^[14].

Carpal tunnel syndrome should be treated conservatively in pregnant women because symptoms often resolve on their own after delivery^[10].

Living With Carpal Tunnel Syndrome

Living with carpal tunnel syndrome requires making adjustments to daily activities and work habits to manage symptoms and prevent the condition from worsening. One of the most important steps is giving your wrists a rest. Since repetitive or extreme wrist motion is a risk factor, simply resting the wrists and keeping them in a neutral position as much as possible can ease pain and numbness^[21].

If your job involves activities such as repetitive assembly line work or typing, talk with your employer about the possibility of rotating tasks to give your wrists and hands a rest^[21]. Making your work station ergonomic is also important. To maintain a good neutral position for your wrist while using a computer, make sure your keyboard and mouse are at the right height to keep your wrists straight. You may also want to use wrist rests in front of your mousepad or keyboard^[21].

Keeping your hands warm can help, as cold conditions can lead to stiffness and worsen carpal tunnel syndrome pain. Consider wearing fingerless gloves, particularly if you work in a cold environment^[21]. Elevating your hands and wrists, especially during sleep, can help ease inflammation. This can be done by sleeping on your back and propping your wrists up on pillows^[21].

Some complementary approaches may provide relief, though strong evidence for their effectiveness is limited. These include acupuncture, yoga, and certain dietary supplements^[1]. Some studies have shown that acupuncture can help with the pain and symptoms of carpal tunnel syndrome^[21]. However, a systematic review found that vitamin B6 and diuretics are no more effective than placebo^[10].

It’s important to seek medical care early. The earlier you start treatment, the better your chances of stopping symptoms and preventing long-term damage to the nerve^[6]. If left untreated, carpal tunnel syndrome can lead to permanent dysfunction of the hand, including loss of sensation in the fingers and weakness^[4]. With proper treatment, most people experience significant relief from their symptoms and can continue their normal activities.