Carpal tunnel syndrome

What is carpal tunnel syndrome

On the palm side of the wrist is a broad tendon band. This ligament holds the flexor tendons in place on their way from the forearm to the fingers. Together with the carpal bones, this ligament forms a tunnel called the carpal tunnel.

Through the carpal tunnel run 9 flexor tendons and the median nerve, which is one of the three major nerves in the forearm and hand. This nerve supplies several muscles in the forearm and hand. It also contains the nerve fibers that give us sensation in the thumb, index finger, middle finger and half of the ring finger (lengthwise) – all on the palm side

What are the symptoms?

• Pain, tingling and numbness and/or decreased sensation in the nerve supply area – most common in the middle finger and index finger
• Reduced strength and muscle wasting in the thumb
• Symptoms often get worse at night or when the arm is held still. Shaking or massaging the hand helps
• Reduced sensation on fingertips makes it difficult to handle small objects such as sewing needles and coins
• Reduced force when thumb is pressed against little finger
• You become more fiddly – dropping things
• Reduced power when bending thumb, index and middle finger

What symptoms should you pay special attention to?

You should pay particular attention to constant loss of sensation and muscle wasting, as these can be signs that the nerve is very pinched.

If left untreated, the damage to the nerve can be permanent, so you won’t benefit as much from surgery.

How is the diagnosis made?

The doctor can make the diagnosis based on the typical symptoms and the findings of the hand and arm examination.

Often you will be referred for a so-called nerve conduction study if surgery is being considered. This is a measurement of how well the nerve conducts the small current impulses that create the brain’s perception of sensation in the fingers.

The velocity of nerve conduction is a measure of how fast these impulses travel through the nerve and will be reduced in carpal tunnel syndrome.

If the diagnosis is reasonably certain based on symptoms and findings, a nerve conduction study is not absolutely necessary, but it can provide information about how much the nerve is affected.

What causes carpal tunnel syndrome?

For various reasons, the space in the carpal tunnel can become too narrow. The median nerve is then pinched and symptoms can occur in the hand and some of the fingers corresponding to the spread of the nerve.

The most common cause is tissue irritation (inflammation). The tissue irritation causes fluid and swelling of the tendon sheaths in the canal, putting pressure on the nerve.

Irritation in the tissue can be caused by tendon irritation or, in some cases, rheumatoid arthritis. Most commonly, however, there is no good explanation as to why the condition has developed. See drawing of carpal tunnel syndrome.

Carpal tunnel syndrome can also be caused by other diseases or injuries. It can be:

• Changes after a bone fracture in the area(wrist fracture)
• Congenital space constraints
• Low metabolism
• Pregnancy
• Diabetes
• Overload through unilateral hand movements during work. Read more about the link between work and carpal tunnel syndrome in the article Carpal tunnel syndrome, work-related