Carpal tunnel syndrome (CTS) is a commonly diagnosed condition but can be poorly understood. Around 2.7% of people will get carpal tunnel syndrome in their lives. You’ve probably heard of carpal tunnel syndrome, but how much do you actually know about it?
In this blog we will explore the anatomy of the wrist, forearm and hand, the symptoms of carpal tunnel syndrome, the causes and what you can do to resolve this, generally without surgery.
The carpal tunnel is a narrow passageway on the palm side of the wrist that allows the median nerve and 9 tendons to pass through it, from the forearm and into the hand and fingers. The transverse carpal ligament creates the roof of the carpal tunnel and the wrist bones (carpals) create the walls and floor (see image).
The 9 flexor tendons include the flexor pollicis longus (flexes the thumb), 4 flexor digitorum profundis and 4 flexors pollicis superficialis (flex the 4 fingers). These tendons originate from the muscles that all originate from the inside of the elbow.
The median nerve runs from the brachial plexus in the neck and travels under the collarbone, through the armpit, to the elbow and then down the middle of the forearm to the fingers, via the carpal tunnel.
The symptoms are the most important part of the diagnosis of carpal tunnel syndrome. These symptoms include:
Tingling or numbness in the thumb, index finger, middle finger and half of the ring finger (the half closet to the middle finger) on the palm side of the hand (see the picture) and the palm. On the back side of the hand it is more the tips of the thumb, index, middle and half of the ring finger that is affected. The rest of the back of the hand and those fingers is innervated by the radial nerve. The ulnar nerve controls the rest of the ring and pinky fingers as well as the pinky side of the hand.
Weakness in the fingers that are innervated by the median nerve. This can manifest by dropping objects.
Aching or pain in these fingers, the palm and/or the wrist.
This is where is gets tricky as there are many opinions and outdated information as to how carpal tunnel is caused.
Hereditary. 50% of people have CTS where it has been passed on from the parents and determined in the genes.
Overuse. People who do repetitive tasks for work using their fingers and hands, such as process factory workers, cleaners, people doing data entry and just computer work in general are found to suffer the most.
Pressure on the wrist. If you use a computer and rest your wrists on the table or laptop then you will be compressing the carpal tunnel. Over time this may form adhesions between the transverse carpal ligament and the median nerve. This can then cause the carpal tunnel syndrome symptoms. You can try getting a gel wrist rest, taking breaks, stretching and adjusting your desk setup to avoid pressure on the wrists.
Diabetes. Diabetes, especially type 1 (genetic and not lifestyle based like type 2) can lead to nerve damage amongst other things. If you have diabetes then you are at a much higher risk of CTS.
Other neurological conditions that affect nerves such as multiple sclerosis, motor neurone disease, Parkinson’s disease and some infections.
Pregnancy. When you are pregnant a whole cocktail of hormones are released that can affect the connective tissues in the body. Especially Relaxin. When this happens the carpal tunnel can collapse and put pressure on the median nerve.
Arthritis. With arthritis the joints of the wrist can swell and create less space in the carpal tunnel. This can then put pressure on the median nerve.
Tendonitis of the wrist tendons can cause swelling that also creates less space in the carpal tunnel and you guessed it compression of the median nerve.
Shape of the wrist. Unfortunately there is not much you can do about this as it is hereditary. It has been found that if you have a square shaped wrist that you are more likely to suffer from carpal tunnel syndrome. A square shaped wrist means that it is a wide as it is long. This would usually present as a narrow wrist and it is thought that this may tighten the ligament and put more strain on the median nerve.
Oedema. Swelling can put pressure on the carpal tunnel. Surgery to remove lymph nodes in the arm pit can lead to swelling in the arms and hands.
Trauma. If you have an injury to the wrist or hand, this may damage the carpal tunnel or increase inflammation and swelling.
How is Carpal Tunnel Syndrome Diagnosed?
Symptoms. This is the simplest diagnosis. If you are having tingling only in the median nerve pattern for the palm and fingers then it is highly likely that you have carpal tunnel syndrome.
Special orthopaedic tests. There are some simple orthopaedic tests that can be performed that will exacerbate the symptoms of carpal tunnel syndrome and isolate them to the wrist, which rules out other nerve impingements such as disc bulges from the neck or nerve impingements at the elbow.
Phalen’s test - place the tops of the hands together in a reverse prayer position (see picture) hold this for at least 30 seconds. A positive test will produce the nerve symptoms. If you think you may have carpal tunnel syndrome then you can do this test to yourself to see. If there are no symptoms then it may not be carpal tunnel. Getting a professional assessment is always essential.
Tinel’s sign - this involves tapping on the carpal tunnel. If the nerve is irritated then it is likely that when tapped you will get a shooting, electric, nerve pain into the thumb, index, middle and half of the ring finger.
Who this affects?
Unfortunately for all of you women carpal tunnel syndrome affects 3 times more women than men. Some thinking is that women tend to have a smaller carpal tunnel which means there is less space for the median nerve to travel. There is also some research to suggest that these statistics may be skewed by more woman having taken up manual tasks.
It is also more likely to affect you if you are between 40 - 50 years old.
Ok, so what can be done about it?
This really depends on how long you have had the issue, how severe it is (weakness or numbness), what you do for work or play and how risk averse you are.
Conservative management. This is always the first step for most injuries. Releasing the forearm muscles and the ligaments in wrist have been shown to take the pressure off the median nerve. Techniques such as Active Release Techniques have been designed to help to release nerve impingements. They do this by pinning the impingement and then using specific movements to move the nerve and getting it gliding again, taking the pressure off it.
Splinting of the wrist. Wearing a wrist splint can help you to avoid positions that may put pressure on the carpal tunnel. This is common when we sleep. You may place your wrist in an extreme flexed or extended position that may irritate the nerve. Wearing a splint when at work can also help to stop the nerve becoming aggravating.
Nerve flossing or gliding for the median nerve. These exercises can help to free up the nerve. These exercises are very useful to prevent carpal tunnel syndrome as well, so if you do a manual job that makes you at risk of CTS then performing these multiple times a day may help keep CTS at bay.
Surgery. Whilst surgery is the last resort. If conservative management hasn’t helped, which means you’ve given it a red hot go, 6 months of treatment, exercises and not aggravating it and the symptoms are still there then surgery will likely be your only option. CTS surgery only takes around 10minutes and can be performed without the use of general anaesthetic. If you aren't squeamish then you can watch a real time CTS surgery here https://www.youtube.com/watch?v=FhALIWs6oP8. There is no blood and it is really quick. If you are considering surgery it may put your mind at ease to see how straightforward this surgery is. As with all surgery there are risks, the biggest here is that they cut the nerve and you lose movement and sensation in 3 fingers and