The anatomy of the wrist and hand, showing the tendons, nerves and bones affected by carpal tunnel syndrome. A symptom of carpal tunnel syndrome, numbness in the hand and fingers, is shown with blue shading.
The carpal tunnel is a space in the wrist that holds tendons and your median nerve. This space is compressed in carpal tunnel syndrome. One symptom of carpal tunnel syndrome is numbness that spreads throughout the hand (see shaded blue area).

What is carpal tunnel syndrome?

Carpal tunnel syndrome is a common condition that causes pain, numbness, tingling, and weakness in the hand and wrist. It happens when there is increased pressure within the wrist on a nerve called the median nerve. This nerve provides sensation to the thumb, index, and middle fingers, and to half of the ring finger. The small finger (the “pinky”) is typically not affected.

Carpal tunnel syndrome was first described in the mid-1800s. The first surgery for the release of the carpal tunnel was done in the 1930s. It is a condition that has been well recognized by orthopaedic surgeons for over 40 years.

What is the carpal tunnel?

The carpal tunnel is a narrow canal or tube in the wrist. Similarly to a tunnel you could travel through by car, this part of the wrist allows the median nerve and tendons to connect the hand and forearm. The parts of this tunnel include:

  • Carpal bones: These bones make up the bottom and sides of the tunnel. They are formed in a semi-circle.
  • Ligament: The top of the tunnel, the ligament is a strong tissue that holds the tunnel together.

Inside the tunnel are the median nerve and tendons.

  • Median nerve: This nerve provides feeling to most of the fingers in the hand (expect the little finger). It also adds strength to the base of the thumb and index finger.
  • Tendons: Rope-like structures, tendons connect muscles in the forearm to the bones in the hand. They allow the fingers and thumb to bend.

Does carpal tunnel syndrome only happen to office workers or factory workers?

No. Many people with carpal tunnel syndrome have never done office work or worked on an assembly line. It affects people who use their wrists and hands repeatedly at work and at play. Anyone can get carpel tunnel syndrome, but it is unusual before age 20. The chance of getting carpal tunnel syndrome increases with age.

Who is at risk for carpal tunnel syndrome?

People at risk for carpal tunnel syndrome are those who do activities or jobs that involve repetitive finger use. Motions that can place people at risk of developing carpal tunnel syndrome include:

  • High-force (hammering).
  • Long-term use.
  • Extreme wrist motions.
  • Vibration.

Many other factors can also contribute to the development of carpal tunnel syndrome. These factors can include:

  • Heredity (smaller carpal tunnels can run in families).
  • Pregnancy.
  • Hemodialysis (a process where the blood is filtered).
  • Wrist facture and dislocation.
  • Hand or wrist deformity.
  • Arthritic diseases such as rheumatoid arthritis and gout.
  • Thyroid gland hormone imbalance (hypothyroidism).
  • Diabetes.
  • Alcoholism.
  • A mass (tumor) in the carpal tunnel.
  • Older age.
  • Amyloid deposits (an abnormal protein).

Carpal tunnel syndrome is also more common in women than in men.

What causes carpal tunnel syndrome?

Carpal tunnel syndrome is caused when the space (the carpal tunnel) in the wrist narrows. This presses down on the median nerve and tendons (located inside the carpal tunnel), makes them swell, which cuts off sensation in the fingers and hand.

How often is hand pain caused by carpal tunnel syndrome?

While carpal tunnel syndrome is a common condition, it has a different set of symptoms from many other sources of hand pain. There are actually several similar conditions that cause hand pain. These include:

  • De Quervain’s tendinosis: A condition where swelling (inflammation) affects the wrist and base of the thumb. In this condition, you will feel pain when you make a fist and simulate shaking someone’s hand.
  • Trigger finger: This condition causes soreness at the base of the finger or thumb. Trigger finger also causes pain, locking (or catching) and stiffness when bending the fingers and thumb.
  • Arthritis: This is a general term for many conditions that cause stiffness and swelling in your joints. Arthritis can impact many joints in your body and ranges from causing small amounts of discomfort to breaking down the joint over time (osteoarthritis is one type of degenerative arthritis).

What are the symptoms of carpal tunnel syndrome?

Symptoms usually begin slowly and can occur at any time. Early symptoms include:

  • Numbness at night.
  • Tingling and/or pain in the fingers (especially the thumb, index and middle fingers).

In fact, because some people sleep with their wrists curled, nighttime symptoms are common and can wake people from sleep. These nighttime symptoms are often the first reported symptoms. Shaking the hands helps relieve symptoms in the early stage of the condition.

Common daytime symptoms can include:

  • Tingling in the fingers.
  • Decreased feeling in the fingertips.
  • Difficulty using the hand for small tasks, like:
    • Handling small objects.
    • Grasping a steering wheel to drive.
    • Holding a book to read.
    • Writing.
    • Using a computer keyboard.

As carpal tunnel syndrome worsens, symptoms become more constant. These symptoms can include:

  • Weakness in the hand.
  • Inability to perform tasks that require delicate motions (such as buttoning a shirt).
  • Dropping objects.

In the most severe condition, the muscles at the base of the thumb visibly shrink in size (atrophy).

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