Carpal Tunnel Syndrome: 

 

Carpal tunnel syndrome is a common condition that causes pain, numbness, and tingling in the hand and arm. The condition occurs when one of the major nerves to the hand — the median nerve — is squeezed or compressed as it travels through the wrist. 

In most patients, carpal tunnel syndrome gets worse over time, so early diagnosis and treatment are important. Early on, symptoms can often be relieved with simple measures like wearing a wrist splint or avoiding certain activities.

If pressure on the median nerve continues, however, it can lead to nerve damage and worsening symptoms. To prevent permanent damage, surgery to take pressure off the median nerve may be recommended for some patients.

 

Anatomy:

The carpal tunnel is a narrow passageway in the wrist, about an inch wide. The floor and sides of the tunnel are formed by small wrist bones called carpal bones.

 

 

 

 

 

 

 

 

The carpal tunnel protects the median nerve and flexor tendons that bend the fingers and thumb.

Reproduced and adapted from Rodner C, Raissis A, Akelman E: Carpal tunnel syndrome. Orthopaedic Knowledge Online Journal. 

The roof of the tunnel is a strong band of connective tissue called the transverse carpal ligament. Because these boundaries are very rigid, the carpal tunnel has little capacity to "stretch" or increase in size.

The median nerve is one of the main nerves in the hand. It originates as a group of nerve roots in the neck. These roots come together to form a single nerve in the arm. The median nerve goes down the arm and forearm, passes through the carpal tunnel at the wrist, and goes into the hand. The nerve provides feeling in the thumb and index, middle, and ring fingers. The nerve also controls the muscles around the base of the thumb.

The nine tendons that bend the fingers and thumb also travel through the carpal tunnel. These tendons are called flexor tendons.

 

Description:

Carpal tunnel syndrome occurs when the tunnel becomes narrowed or when tissues surrounding the flexor tendons swell, putting pressure on the median nerve. These tissues are called the synovium. Normally, the synovium lubricates the tendons, making it easier to move your fingers.

When the synovium swells, it takes up space in the carpal tunnel and, over time, crowds the nerve. This abnormal pressure on the nerve can result in pain, numbness, tingling, and weakness in the hand. 

 

Carpal tunnel syndrome is caused by pressure on the median nerve as it travels through the carpal tunnel.

Most cases of carpal tunnel syndrome are caused by a combination of factors. Studies show that women and older people are more likely to develop the condition.

Other risk factors for carpal tunnel syndrome include:

• Heredity. This is likely an important factor. The carpal tunnel may be smaller in some people or there may be anatomic differences that change the amount of space for the nerve—and these traits can run in families.

• Repetitive hand use. Repeating the same hand and wrist motions or activities over a prolonged period of time may aggravate the tendons in the wrist, causing swelling that puts pressure on the nerve.

• Hand and wrist position. Doing activities that involve extreme flexion or extension of the hand and wrist for a prolonged period of time can increase pressure on the nerve.

• Pregnancy. Hormonal changes during pregnancy can cause swelling.

• Health conditions. Diabetes, rheumatoid arthritis, and thyroid gland imbalance are conditions that are associated with carpal tunnel syndrome.

 

Symptoms:

Symptoms of carpal tunnel syndrome may include:

• Numbness, tingling, burning, and pain—primarily in the thumb and index, middle, and ring fingers

• Occasional shock-like sensations that radiate to the thumb and index, middle, and ring fingers

• Pain or tingling that may travel up the forearm toward the shoulder

• Weakness and clumsiness in the hand—this may make it difficult to perform fine movements such as buttoning your clothes

• Dropping things—due to weakness, numbness, or a loss of proprioception (awareness of where your hand is in space)

 

In most cases, the symptoms of carpal tunnel syndrome begin gradually—without a specific injury. Many patients find that their symptoms come and go at first. However, as the condition worsens, symptoms may occur more frequently or may persist for longer periods of timn a .

Night-time symptoms are very common. Because many people sleep with their wrists bent, symptoms may awaken you from sleep. During the day, symptoms often occur when holding something for a prolonged period of time with the wrist bent forward or backward, such as when using a phone, driving, or reading a book.

Many patients find that moving or shaking their hands helps relieve their symptoms.