What is it?
Carpal tunnel syndrome is a condition brought on by a pinched median nerve at the wrist, which sometimes causes numbness, tingling and pain in the arm, hand and fingers. The syndrome occurs when pressure builds up from the swelling in the carpal tunnel area, placing pressure on the nerve.
The carpal tunnel is located at the wrist on the palm side of the hand just beneath the skin surface (palmar surface). Eight small wrist bones form three sides of the tunnel, giving rise to the name carpal tunnel. The remaining side of the tunnel, the palmar surface, is composed of soft tissues, consisting mainly of a ligament called the transverse carpal ligament. This ligament stretches over the top of the tunnel.
The median nerve and nine flexor tendons, which help flex or bend the finger, pass through the carpal tunnel. When this median nerve in the wrist is compressed (squeezed by swollen tissues, for example), it slows or blocks nerve impulses from travelling through the nerve. Disabling the nerve results in symptoms ranging from mild occasional numbness to hand weakness, loss of feeling and loss of hand function.
Carpal tunnel syndrome can be triggered by swelling of the lining of a tendon (tenosynovitis) and is often associated with repetitive use of the hands. Bone dislocations, fractures and arthritis can also narrow the tunnel, but are usually not as common. Fluid retention during pregnancy can also be a temporary source of carpal tunnel syndrome. Medical conditions such as hypothyroidism, rheumatoid arthritis and diabetes can also trigger the disease. What are the symptoms?
Pain, numbness, tingling (or a combination of the three) in one or both hands is a symptom of carpal tunnel syndrome. (It generally occurs in the thumb, index, middle and ring fingers.)
Symptoms generally occur during the night but can be felt during daily activities such as driving or reading a newspaper.
Patients sometimes have a weaker grip and, as a result of carpal tunnel and may drop things.
In severe cases of carpal tunnel, sensation may be permanently lost and the muscles at the base of the thumb deteriorate (thenar atrophy). How is it diagnosed?
During physical examination, testing may identify weakness of the muscles supplied by the median nerve in the hand including some thumb muscles affected by carpal tunnel syndrome. Carpal tunnel patients may experience decreased sensation in the hand to pin prick or light touch. Bending the wrist to 90 degrees for one minute may cause symptoms to appear in the hand (Phalen test) or tapping on the wrist with a reflex hammer may cause an electric shock-like sensation (Tinel’s sign).
In patients who have experienced carpal tunnel disease for a long time may have thinning of the muscles or muscle atrophy at the base of the thumb. Electrical tests to stimulate nerves and measure the degree of abnormal function of the muscles can diagnosis carpal tunnel syndrome and determine its severity.
In recent years, diagnostic ultrasonography and MRI scans
have been used to help diagnose carpal tunnel syndrome and exclude other causes of hand and wrist symptoms. How is it treated?
Many times, carpal tunnel symptoms can be eliminated without surgery. Changing activities to reduce repetitive or strenuous use of the hand or keeping the wrist in a straight position may help reduce the swelling, allowing more room for the nerve. Wearing wrist splints during the night may relieve carpal tunnel symptoms and allow for better sleep. Anti-inflammatory medication or injections of corticosteroid drugs into the wrist may also help relieve carpal tunnel symptoms.
Some have turned to alternative therapies. Yoga, for example, has been shown to reduce pain and improve grip strength among patients with carpal tunnel syndrome.
When symptoms are severe and do not improve, surgery to enlarge the carpal tunnel and decrease pressure on the nerve may be indicated. This is usually done on an outpatient basis with local or regional anesthesia.
Following surgery for carpal tunnel syndrome, soreness around the incision may last for several weeks or months. The numbness and tingling may disappear quickly or slowly. It may also take several months for strength in the hand and wrist to return to normal. It is important to remember that returning to strenuous work after surgery can cause the symptoms to return.
The Sentara Hand Therapy Program
offers specialists who have received extensive training under experts certified by the American Society for Hand Therapists. Certified hand therapy services are available at select outpatient centers within the Sentara Therapy Services
. What research is being done?
and clinical trial information
on carpal tunnel syndrome, visit the National Institutes of Health Web sites
. Can it be prevented?
At the workplace, employees can do on-the-job conditioning, perform stretching exercises, take frequent rest breaks, wear splints to keep wrists straight, and use 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. -- Sources:
-- The National Institute of Neurological Disorders and Stroke
-- American Physical Therapy Association
-- American College of Rheumatology