Members of faculty of the Hand Program at Beth Israel Deaconess Hospital–Needham are national leaders in investigating new ways to treat this increasingly common condition. They have published dozens of research articles.

Carpal Tunnel Hand DiagramGeneral Information on Carpal Tunnel Syndrome

Carpal tunnel syndrome is caused by a compressed nerve in the wrist, which subsequently causes symptoms in the hand. Pressure on the median nerve, which is inside a narrow passage in the wrist called the carpal tunnel, causes the nerve to malfunction. This nerve provides feeling to the thumb, index and middle fingers, and half the ring finger. It also controls several muscles in the hand, the most important of which allows the thumb to touch the little finger. Compression occurs when the tissues in the carpal tunnel swell up.


Carpal tunnel syndrome is a repetitive strain injury. Although there are many causes for carpal tunnel syndrome, by far the most common is doing repetitive motions as part of your job. Fragmentation of work to the point that one person does one task over and over has been blamed for the increase in cases of carpal tunnel syndrome in recent years. There are approximately one million new cases every year.


Anything that causes irritation, inflammation, fluid retention, or an abnormal growth in or around the carpal tunnel can cause carpal tunnel syndrome, including

  • Repetitive movements of the hands, wrists, or fingers-especially overactive use of a computer keyboard, certain musical instruments, or hand tools
  • Use of vibrating equipment or tools
  • A narrow carpal tunnel (due to heredity)
  • Wrist injury
    • Burns
    • Broken bones
    • Compression or crush injuries
  • Arthritis 
  • Diabetes 
  • Raynaud's disease, which impairs blood flow in the hands
  • Water retention due to
    • Kidney disease
    • Heart disease 
  • Hormone-related conditions, such as
    • Pregnancy
    • Breastfeeding
    • Menopause 
    • Hypothyroidism 
    • Cushing's disease 
    • Excess growth hormone
  • Medications, such as
    • Birth control pills
    • Cortisone pills or shots
    • Some high blood pressure drugs
    • Tumors and cysts in the carpal tunnel

Risk Factors

It is possible to develop carpal tunnel syndrome with or without the risk factors listed below. However, the more risk factors you have, the greater your likelihood of developing carpal tunnel syndrome. If you have a number of risk factors, ask your doctor what you can do to reduce your risk.


The vast majority of carpal tunnel syndrome cases are work related. People whose occupations involve repetitive work with the hands, such as keyboard operators, factory workers, typists, barbers, musicians, and vehicle drivers, are at increased risk. In addition, people who use vibrating tools, such as jack hammers, chain saws, chippers, grinders, drills, and sanders, for long periods everyday may be at increased risk.


Wrist injuries, such as burns, broken bones, compression, or crush injuries, may increase your risk of developing carpal tunnel syndrome.

Medical Conditions

Having the following medical conditions may increase your risk of developing carpal tunnel syndrome

  • Arthritis
  • Diabetes
  • Raynaud's disease, which impairs blood flow in the hands
  • Water retention due to:
    • Kidney disease
    • Heart disease
  • Hormone-related conditions, such as:
    • Pregnancy
    • Breastfeeding
    • Menopause
    • Hypothyroidism
    • Cushing's disease
    • Excess growth hormone
  • Medications, such as:
    • Birth control pills
    • Cortisone pills or shots
    • Some high blood pressure drugs
    • Tumors and cysts in the carpal tunnel


Carpal tunnel syndrome is most often diagnosed between the ages of 40-60.


Women are diagnosed with carpal tunnel syndrome three times more often than men.

Genetic Factors

Inheriting a narrowed carpal tunnel increases your chances of developing carpal tunnel syndrome.


Carpal tunnel syndrome causes symptoms in one or both hands that, more rarely, may also extend up the arm. Symptoms are caused by compression of the median nerve in the carpal tunnel. This nerve supplies feeling to the thumb, index, middle, and half the ring finger. It also innervates the muscles that move the thumb toward the little finger and move the index finger around in a circle.

Symptoms include

  • Tingling, burning, or numbness, especially in your thumb and index or middle fingers
  • Pain or numbness that worsens with
    • Wrist, hand, or finger movement
    • Sleep (symptoms may wake you)
  • Hand stiffness or cramping that gets better after
    • Shaking the hand
    • Waking up in the morning
  • Weakness or clumsiness of your hand
    • Loss of grip strength
    • Difficulty touching your little finger with your thumb
    • Frequently dropping things
  • Pain extending up your arm


The doctor will ask about your symptoms and medical history, and examine your neck, arms, wrists, and hands. The physical exam will include tests of strength, sensation, and signs of nerve irritation or damage.

The physical exam may include

  • Tinel's Sign
    The doctor will tap firmly on your wrist right over the carpal tunnel to see if it sends an electric shock feeling into your hand. You can actually do this test yourself, as well. Tap right over the creases on the inner side of your wrist between the two bones on either side of the base of your palm.
  • Compression Test
    The doctor will bend your wrist down so that your thumb comes as close to your forearm as it will go, and then hold it there for a minute or two to see if it causes tingling and numbness in your hand.

Other tests may include

  • Nerve Conduction Study
    The speed at which your nerves carry signals can be determined by stimulating them with tiny electrodes attached to special machines. If conduction is slowed through the carpal tunnel, you probably have a problem in the carpal tunnel.
  • Electromyogram (EMG)
    In a similar fashion, tiny currents can be used to stimulate muscles. The muscles respond with electrical activity that can be measured. When the nerves connecting to muscles are damaged, the muscles give off abnormal signals.
  • X-rays, CT Scan, and MRI Scan
    These imaging tests may identify other causes of carpal tunnel syndrome or give more extensive information as to your particular problem.
  • Arthroscopy
    This procedure is useful in both diagnosing and treating carpal tunnel syndrome. This is a minor surgical procedure during which a thin, lighted tube (arthroscope) is inserted into your wrist. The surgeon can then look through the tube to see exactly what is wrong. The same tube can be used to repair the problem, using tiny tools inserted through the arthroscope into the wrist.


The treatment and management of carpal tunnel syndrome requires that pressure in the carpal tunnel be reduced. There are several ways to do this. As with all health problems, the safest and simplest treatments are tried first. If your carpal tunnel syndrome is due to another treatable condition, such as diabetes or a hormone disorder, that condition may be treated first to see if the carpal tunnel syndrome resolves.

To treat carpal tunnel syndrome directly, the options are

  • Rest and exercises
  • Splinting
  • Medications
  • Cortisone injections
  • Carpal tunnel release surgery
  • Mirza Procedure

Reducing Your Risk

Carpal tunnel syndrome is most often caused by activity associated with repetitive hand motion on the job. Those most at risk, such as keyboard operators, factory workers, typists, musicians, barbers, and bus drivers, can do much to prevent development of carpal tunnel syndrome. Ergonomic specialists can help you set up your workplace to be as comfortable and efficient as possible.

Lifestyle Changes

You may reduce your chances of getting carpal tunnel syndrome by taking these steps

  • Minimize repetitive hand movements when possible.
  • Alternate between activities or tasks to reduce the strain on your body.
  • When using your wrists, keep them straight and let your arms and shoulders share the stress.
  • Use your whole hand or both hands to pick up an item.
  • Avoid holding an object the same way for a long time.
  • If you work in an office, adjust your desk, chair, and keyboard so you are in the best possible position
    • Back straight
    • Feet flat on the floor or resting on a footrest
    • Knees level with or slightly lower than your hips
    • Shoulders in a neutral position, not forward or back
    • Elbows bent at a 90 degree angle
    • Forearms parallel to the floor and wrists straight
  • Take breaks at least once an hour to
    • Rest or shake your hands.
    • Massage the palms and backs of your hands.
    • Do a few stretches and loosening movements of the shoulders and arms before settling in to work. Do them often during the day.
  • Keep hands warm, with gloves if necessary.
  • Get regular aerobic exercise such as walking or swimming.
  • Cut down on caffeine and smoking, which may reduce blood flow to your hands.


According to a report published by the American Academy of Orthopaedic Surgeons, a simple warm-up routine may greatly reduce the incidence of carpal tunnel syndrome. The warm-up routine is as follows

  • Hold your hands in front of you as if pushing on a wall. Count to five.
  • Relax your wrists and fingers.
  • Make tight fists with both hands.
  • Bend both fists downward. Count to five.
  • Repeat each step ten times.
  • Then shake arms loosely while hanging at your side.

Sleeping Position

A simple change in how your wrists are positioned during sleep may reduce your risk of getting carpal tunnel syndrome. Sleep with your wrists cocked upward instead of bent downward to minimize pressure in the carpal tunnel.