The carpal tunnel is a narrow passageway that runs from the wrist (the carpus) to the hand. Its bottom and sides are formed by small bones, and the top is a band of rigid connective tissue. Running through this tunnel is the median nerve, one of the main nerves in the hand, and nine flexor tendons that allow you to bend and flex your fingers. Carpal tunnel syndrome occurs when the median nerve becomes compressed, reducing its blood supply.
Carpal tunnel syndrome comes from doing activities that involve frequent, repetitive movements or extreme flexion or extension of the hand and wrist for long periods of time. These motions can aggravate any of those nine tendons and lead to swelling that puts pressure on the nerve.
Carpal tunnel syndrome is often linked to computer work, texting, or video gaming, but it can occur with low-tech activities too, such as painting and knitting. People who work in construction and use vibrating equipment, such as a jackhammer, are also at risk.
Additional risk factors include being born with a smaller carpal tunnel than average or one with less space for the nerve. (Both issues can run in families.) Having diabetes, an autoimmune disorder such as rheumatoid arthritis, or obesity also increases risk.
The earliest symptom of carpal tunnel syndrome is usually numbness or tingling in the affected hand at nighttime or when waking up in the morning. You’ll feel these sensations in the fingers through which the median nerve courses, so not on the pinkie side of the ring finger or the pinkie. Symptoms there signal a different problem. Pain and a burning sensation are also common.
Sometimes, symptoms spontaneously resolve. But if they do not, and carpal tunnel syndrome progresses, you may experience symptoms throughout the day, especially when you’re doing activities with repetitive motions. You may experience shock-like twinges that radiate across your first four fingers. Pain or tingling may run up your arm toward your shoulder. You may sense weakness in your hand and feel clumsy. You might have a hard time getting dressed or frequently drop things.
Over time, your symptoms can become constant. While your dominant hand is usually the first to be affected, many people develop carpal tunnel syndrome in both hands. If carpal tunnel is left untreated, you run the risk of permanent nerve damage, with loss of feeling as well as weakness. This is why it’s so important to get an evaluation from a hand specialist, ideally a hand surgeon, for symptoms that last more than two to three days. The earlier the intervention, the better the prognosis.
Your doctor will likely begin with a physical exam to look for sensory and motor signs that point to carpal tunnel syndrome while ruling out other conditions. One key sensory exam is called the carpal compression test. It simply involves applying pressure directly over the carpal tunnel for 30 seconds to see if this provokes symptoms.
For a definitive diagnosis, your doctor may do an electromyography and nerve conduction study to look for specific abnormalities that indicate carpal tunnel syndrome. This test can also rule out other conditions that can cause numbness and tingling, such as cervical radiculopathy (a pinched nerve in the neck), diabetic neuropathy, or nerve compression elsewhere in the arm. Test results also help determine whether your carpal tunnel syndrome is mild, moderate, or severe and the extent of any nerve damage.
In the early stages, conservative steps may bring relief. The initial treatment is usually wearing a wrist splint at night for sleeping. The splint keeps your wrist in a neutral position to maximize the space within the carpal tunnel. Sleeping with the wrist in a flexed or extended position can put more pressure on the median nerve, producing symptoms. Here are some additional strategies:
Other treatment options include cortisone injections and surgery. Cortisone injections are usually helpful but typically provide only temporary improvement.
Carpal tunnel surgery, called carpal tunnel release, increases the size of the tunnel and relieves the nerve compression. It usually results in permanent improvement. Surgery is minimally invasive and performed on an outpatient basis, frequently under local anesthesia. Most people can use their hand immediately afterward. Carpal tunnel release is the best treatment option for severe or stubborn cases.
Approaches such as therapy, lasers, acupuncture, and manipulation have been tried, but frequently are not helpful and can even be harmful. Over-the-counter medications like nonsteroidal anti-inflammatory drugs (NSAIDs) often don’t help enough. They might ease pain from inflammation, but not the tingling or burning. Working with a hand specialist remains the best approach to get a handle on carpal tunnel syndrome.
If you do any kind of work or hobby that puts you at risk of carpal tunnel syndrome, from typing to knitting to working with power tools, try these strategies to reduce your risk:
Make a fist, and then fan out your fingers.
Rotate your wrist up and down to relieve stiffness.
Put your palms together over your head, move your hands downward as far as you can, and hold for five to 10 seconds.
Push your thumb back until you feel a gentle stretch.
Hold your left hand out, with the palm facing down. Use your right hand to pull the left back until you feel a stretch. Switch sides.
