Carpal tunnel syndrome is a condition where one of the major nerves of the arm gets compressed in the wrist. It can lead to pain, numbness, and tingling in the hands. Advanced symptoms are muscle weakness in the hands, muscle atrophy (shrinking), especially of the thumb pad; and loss of motor coordination in fine dexterity skills, like buttoning a blouse.
The three main nerves that are responsible for controlling the arm are the ulnar, median, and radial nerves. The median nerve, like its name implies, travels down the middle of the arm. It passes through the carpal tunnel which is just above the crease in the wrist before splitting into branches that go to the thumb, index, middle, and inner half of the ring finger.
The carpal tunnel is a small diameter hole formed by the wrist bones and the transverse carpal ligament. It contains the tendons that flex the fingers (flexor tendons), and the median nerve. Pressure as light as a penny can adversely affect nerve tissue, so any pressure increase in the carpal tunnel will over time injure the median nerve.
The most common cause of increased pressure in the carpal tunnel is thickening of the flexor tendons due to long term repetitive use of the fingers such as in typing. Over time the tendons press the median nerve against the rigid transverse carpal ligament. The nerve loses oxygen and it starts to malfunction. Left alone, the damage will be permanent as nerves have a limited ability to regenerate.
Other possible causes are prior injury to the wrist that narrows the carpal tunnel and arthritic or other pathological changes in the wrist bones that cause them to occlude the tunnel.
Pregnancy and thyroid conditions may mimic symptoms of carpal tunnel syndrome.
If the symptoms are advanced (pain, numbness, tingling especially at NIGHT and loss of hand coordination and muscle atrophy) see your doctor. The doctor should refer you to a hand specialist who may order a nerve conduction test to diagnose carpal tunnel syndrome. If your test is positive, you may be referred for physical therapy, which will involve mostly stretching and hand exercises. If that doesn’t work, you may be offered a cortisone injection and exercise prescription, a wrist brace and orders to avoid prolonged hand usage. The last option is carpal tunnel release surgery, where the transverse carpal ligament is surgically cut to relieve pressure in the tunnel.
If your condition is not advanced, do the following:
If your job or hobby requires lots of finger and hand activity, there is a good chance that this is the cause of your symptoms. Check your work station set up and ensure the following:
a. Keyboard should be low enough so that your fingers are at the level of the keyboard when:
- your upper arms and shoulders are relaxed; your upper arms (above the elbow) are to the side of your body almost touching;
- your elbows are bent 90-100 degrees
- your wrists are straight or even bent slightly downward
The most important part is having your shoulders relaxed. To see if you are doing it right, using your right hand press the top of your left upper shoulder, from the neck down to the shoulder joint. It should be relatively soft. If it is not, you are unconsciously contracting the neck and upper trapezius muscles and lifting the arm.
If you find you can’t accomplish the above, due to your desk being too high, you need to get an adjustable keyboard tray and install it under your desk. Place the keyboard on this tray and lower and angle the tray so that you can meet these requirements (see video below on how to do this).
b. The top 1/3 of your monitor screen should be at eye level. Use phone books or a monitor lift to get it to this position. Place the monitor close enough that you don’t have to bend your neck forward to see text on your screen, or adjust your screen settings to magnify the text.
c. The mouse and frequently used equipment should be close so that you don’t have to reach forward for them. Your keyboard tray should have an attached mouse pad; use it.
d. Remember to keep your head in a position where your ears are directly over your shoulders.
e. Every few minutes, relax your hands and wrists for 20-30 seconds.
f. Every hour do the wrist, neck and shoulder exercises in the video.
g. When symptoms are gone, you can do wrist strengthening exercises.