The carpal tunnel is an opening in the wrist that the median nerve passes through. It is a tight squeeze for the median nerve, which must share the narrow space with nine tendons (tissue that connects muscles to the finger bones). The median nerve sends feeling to the thumb and fingers (except the little finger). The nerve also lets the thumb touch the tip of the other fingers. You need the median nerve for a steady grip and to hold things.
What is carpal tunnel syndrome?
Carpal tunnel syndrome is a painful condition in the wrist. It's caused by compression of the median nerve as it passes through the carpal tunnel. When this nerve gets squeezed or pressed at the wrist, it can cause numbness, pain and weakness in the hand. As symptoms get worse, you may have a tingling feeling and progressive weakness in your grip. You may have a tendency to drop objects. Symptoms can be worse at night and interrupt sleep.
What causes carpal tunnel syndrome?
The problem is not the median nerve itself. Factors or conditions that reduce space in the carpal tunnel can increase pressure on the nerve, causing carpal tunnel syndrome. One factor is genetic - some people are born with a narrower carpal tunnel and are more susceptible to the condition. Other factors may include:
- Pregnancy
- Obesity
- Injury to the wrist
- Overactive pituitary gland
- Underactive thyroid
- Diabetes
How is it diagnosed?
Your doctor can often diagnose carpal tunnel by a physical exam and by how you describe your symptoms.The doctor will ask you about your symptoms and to describe the nature of your job, hobbies and other activities where you use your hands. Answer these questions before your visit:
- What am I doing when I feel the symptoms?
- Do the symptoms go away on the weekend or when I stop performing certain activities?
- What medical conditions do I have? (Diabetes, an underactive thyroid and other illnesses can make you more likely to get carpal tunnel syndrome.)
Your doctor will examine your hands, arms, shoulders and neck to try to find the cause of your pain. She or he may also try to reproduce the symptoms by tapping or pressing on the nerve in your wrist to see if you have any tingling or pain. Lightly tapping on your wrist or bending your wrist down for up to three minutes - two maneuvers that may bring a milder version of your symptoms - may also be done to help confirm the diagnosis of carpal tunnel syndrome.
In some cases, your doctor may suggest further testing to rule out other conditions or determine the amount of nerve damage to help guide treatment. Tests may include nerve (conduction studies) and muscle tests (electromyography, or EMG).
- A nerve conduction test involves placing electrodes on the skin of fingers and wrist. A tiny electrical current is passed through the nerve. Slowing of conduction through the median nerve in the carpal tunnel is a sign of carpal tunnel syndrome.
- An EMG involves inserting a needle into muscles supplied by the median nerve to measure the nerve response. If the muscle contracts abnormally, nerve damage may be suspected.
How is carpal tunnel syndrome treated?
Damage to nerves or muscles can occur if carpal tunnel syndrome is not treated. Your doctor may recommend:
- A wrist splint. Your doctor may prescribe a wrist splint to wear at night to keep your wrist immobilized while you sleep. This lessens swelling and helps reduce the pain that may keep you awake. A splint may also be worn during the day or while doing any aggravating activities.
- Pain medications. Your doctor may prescribe acetaminophen (such as Tylenol) or ibuprofen (such as Advil or Motrin) to reduce swelling, relieve pain and promote healing.
- Injections. Corticosteroids, such as prednisone, may be injected into the wrist to help relieve pressure on the nerve.
- Surgical treatment. If symptoms continue or get worse with conservative (nonsurgical) treatment, you may be offered surgery. The procedure is called a carpal tunnel release. It involves opening the tunnel to relieve pressure on the median nerve. The surgery can be done as an open procedure, or with tiny incisions using a lighted scope (endoscopy). Both the open and closed procedures are usually done on an outpatient basis.
What can I do to prevent carpal tunnel?
Carpal tunnel related to workplace injury may be prevented with certain steps, such as:
- Using correct posture when sitting and keeping the wrists in a natural position
- Wearing fingerless gloves to keep hands warm and protected
- Redesigning workstations, handles and tools to protect the wrist
- Stretching exercises for the arm and wrist
