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Carpal Tunnel Syndrome


Compression of the ‘Median nerve’ at the level of the wrist. This nerve supplies power to the large muscle at the base of the thumb and also is responsible or the sensation in the thumb, index and part of middle finger. At the wrist, it runs through a tunnel (‘Carpus’ – latin for hand). The roof of the tunnel is formed by a strong ligament. If the tunnel narrows, it compresses the nerve. Carpal Tunnel Syndrome (CTS) is most common in middle aged patients and occurs more frequently in women. In more than half of all patients it is present in both hands but usually worse on the dominant hand. There are several possible causes. It is often seen in patients who do repetitive hand movements like working on computers or patients with other conditions like diabetes. It can also occur during or after pregnancy.


It often starts with pins and needles in the thumb, index and middle finger. Patients have to shake or move their hands to improve it. It commonly is worst at night and might wake patients up from sleep. It can progress to pain around the wrist and forearm. In severe cases, it affects the thumb muscles and can cause weakness of the hand. The muscle can start to waste and become visibly thinner. Patients may notice difficulties opening tins or bottles.

Clinical signs

When bending the wrist 90 degree or as much as possible for 30-60 seconds it often reproduces the pins and needles (Phalen’s test). It is positive in the vast majority of patients.


Permanent numbness of the thumb, index or middle finger or weak grip.


Patients should always have Electrophysiological tests (nerve conduction studies) to confirm the diagnosis. These tests check how well the ‘electricity’ goes through the nerve and if the blockage is at the level of the wrist. Pressure on nerves as they leave the spine (radiculopathy) can cause very similar symptoms and an MRI scan of the cervical spine (neck) might be indicated in unclear cases.


In mild and moderate cases a night splint for the wrist can be very useful. Avoiding repetitive hand/ finger movements like using a computer keyboard might also help. If rest is not sufficient, a carpal tunnel injection might be helpful.

Surgery in form of a carpal tunnel decompression is indicated, if conservative treatment has failed or if the compression is severe.

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