The carpal tunnel is a space made by the wrist bones (carpals) and soft tissues. It creates a passage for nerves, tendons, and blood vessels to pass into the hand. Carpal tunnel syndrome is a collection of symptoms that can develop when one of the nerves within the tunnel is irritated, which can happen for a number of reasons.
What Causes Carpal Tunnel Syndrome?
Causes of CTS can be broken down into three categories:
- external pressures on the tunnel
- compression from within the wrist
- genetic factors
External pressures can include repeated pressure from a work surface on the wrist, such as a keyboard or desk that is poorly set up for you. Your osteopath can advise you on making your work set-up more comfortable. One size does not fit all when it comes to ergonomics, and making changes to ease the wrist can cause problems elsewhere if the approach is not holistic.
Compression within the risk is often due to fluid retention, but can also be caused by other problems like ganglions. A ganglion is a pocket of swelling from within a joint. These are usually painless, visible lumps that form on the wrist. They may resolve on their own, or sometimes they might need to be drained. Generally they cause few problems, but if they cause carpal tunnel syndrome symptoms, they would be worth investigating further.
Fluid retention can cause overcrowding within the tunnel, irritating the nerve. Some medications and conditions are associated with fluid retention, as is pregnancy. Kidney and heart disease often cause a build up of fluid within the tissues. Your GP may be able to give you medications to reduce this; and we can give temporary relief with treatment and exercise.
Overuse injuries, such as repetitive strain injury (RSI) can also affect the carpal tunnel. Again, this could be related to your job, or it might be associated with sport. Racquet sports demand a lot of the wrist flexor and extensor muscles, whose tendons pass through the tunnel. Friction or inflammation here can cause problems for the other structures in the tunnel.
Symptoms of CTS
The image above shows the area most commonly affected by CTS. This is the area supplied by the ulnar nerve, which is the structure typically irritated by CTS. The nerve has both motor and sensory functions. This means that symptoms can manifest as pain, pins and needles, or numbness, but also weakness. Long term CTS can cause wasting of the hand muscles in this area if left untreated. The wasting of the large muscle at the base of the thumb can be quite stark. Unsurprisingly, the effect on hand function can be very limiting. Fortunately, hand rehabilitation is quite simple once the nerve is released.
Similar symptoms further up the arm can be mistaken for CTS, but are very unlikely to be part of the same problem. Compression of the same nerve can occur around the elbow (cubital tunnel syndrome). In this case treating the wrist would not affect the root cause. Nerves can also be irritated around the shoulder (thoracic outlet syndrome) or where a nerve leaves the spinal cord (nerve root irritation). However, these last two would not follow the same exact same pattern of symptoms, as the ulnar nerve has not formed at this point.
Managing Carpal Tunnel Syndrome
Your osteopath’s approach to managing your CTS will depend on the factors involved. If fluid retention is a major cause, then drainage techniques and exercises at home may be the best course of action. It may also be worth you speaking to your GP about your medications if they cause fluid retention. If your work irritates the tunnel from the outside, we can help you find ways to mitigate it. Changes to your ergonomics, as mentioned above, might be the first step. Again, exercises can be useful to keep on top of your symptoms, and hands on treatment would aim to improve the general health and movement of the area.
Sometimes surgery is the most appropriate course of action for someone with CTS. However, the NHS guidelines recommend that most people try a six week course of conservative treatment, which could include exercises and hands-on treatment to mobilise the nerve. They also recommend an overnight wrist splint, to prevent further compression at a time when you are relatively likely to hold your wrist in a flexed position for a long period. Splints are not recommended during the day, as movement is usually one of the best things you can do for the wrist.
- nhs.uk. 2022. Ganglion cyst. [online] Available at: <https://www.nhs.uk/conditions/ganglion/> [Accessed 12 August 2022].
- Cks.nice.org.uk. 2021. Scenario: Management | Management | Carpal tunnel syndrome | CKS | NICE. [online] Available at: <https://cks.nice.org.uk/topics/carpal-tunnel-syndrome/management/management/> [Accessed 12 August 2022].
- Jones, O., 2021. The Brachial Plexus. [online] Teach Me Anatomy. Available at: <https://teachmeanatomy.info/upper-limb/nerves/brachial-plexus/> [Accessed 12 August 2022].