VDTs and Your Health - Arms and Hands

Arms and Hands Topics

About the Arms and Hands

Arm, wrist and hand discomfort problems are reported far less frequently by VDT users than neck, back or eye discomfort. However, when problems occur in this area, they can be very serious and may require medical attention.

The muscles of your shoulder control the movement of your upper arm. In turn, the muscles of your upper arm control the movements of your lower arm.

Hand and finger movement is controlled by the muscles in your forearm. These muscles are connected by tendons near the elbow at one end which travel through the wrist and are connected to the hand and fingers.

Nerves control the muscle movement of your arms, hands and fingers, and carry sensory information back to your brain. They originate in the spinal cord and travel through the neck, vertebrae, around and between the bones and muscles of your shoulder, down your arms, through your wrists and to the hands and fingers. The two main nerves that control finger movement are the ulnar and median nerves.

Of greatest concern to VDT users is the median nerve. This nerve travels through the wrist by way of a narrow structure called the carpal tunnel.

The carpal tunnel is formed on top by small bones of the wrist and on the bottom by a ligament. In addition to the median nerve, the carpal tunnel is shared by the tendons from your forearm muscles which control finger and hand movement and by blood vessels. The carpal tunnel structure is where nerve and tendon problems can originate.

Causes of Arm and Hand Problems

Cumulative Trauma Disorder (CTD) is a term used to classify general disorders of the shoulders, arms and hands which result in strains or sprains over a long period of time. Other terms which essentially mean the same thing are; Repetitive Strain Injury (RSI), Repetitive Motion Injury (RMI) and Overuse Syndrome. There are four main factors that have been associated with CTD. They are: repetition, awkward or static postures or positions, using excessive force and mechanical stress or pressure.

There are two main types of cumulative trauma disorders - tendon disorders and nerve disorders. In general, tendon disorders are typically a precursor to nerve disorders. As a result, an early warning sign of a more serious problem (nerve disorders) is the discomfort associated with tendon disorders. Tendon disorders are an inflammation and thickening of the tendon and/or tendon sheath due to repeated tensing of the muscle and tendon. This is a cause of pain near the joints of the elbow, wrists or fingers. A good example of a tendon disorder is the sports injury "tennis elbow," an inflammation of the tendons attached to the elbow. This condition occurs over a period of time when a tennis player repetitively hits the ball with a high amount of force.

Other tendon disorders occur in the protective sheath that surrounds the tendon. Due to excessive movements, extra lubricant fluid is produced to help the tendons move smoothly.

This causes the sheath to become swollen and results in pain or constriction of the tendon within the sheath.

Carpal Tunnel Syndrome (CTS) is a nerve disorder which affects the wrist and fingers and is potentially very serious. The Carpal Tunnel is the narrow structure where tendons, blood vessels and the median nerve pass through the wrist to the fingers. If the tendons become swollen and inflamed, there is less room for the median nerve within the Carpal Tunnel. This causes compression of the median nerve.

When this occurs, pain, numbness and a tingling sensation of the first three fingers and the base of the thumb result.

Of all the arm and hand problems that are associated with VDT use, Carpal Tunnel Syndrome is rare. CTS can be treated with steroids, anti-inflammatories or physical therapy. But quite often, this problem results in corrective surgery to loosen the transverse ligament and alleviate the symptoms.

Another potential problem area is arm muscle fatigue. This occurs primarily due to steady contraction of the muscles in both the upper and lower arms. This can cause your muscles to fatigue and begin to ache.

Preventing Arm and Hand Problems

Although problems of the arms and hands associated with VDT work can be very serious, there are very simple and straight forward methods you can use to minimize these problems from occurring.

In the prevention of cumulative trauma disorders, it is absolutely essential that you understand and practice good posture. This means that your VDT equipment must be set-up correctly to fit your physical stature. You need to pay particular attention to your keyboard placement and height as well as your chair height.

These adjustments should be made in order to allow you to keep your forearms parallel to the floor and your wrists straight (neutral) while keying. By keeping your wrists in a neutral position, you prevent the build up of excessive pressure that would occur on the tendons in the Carpal Tunnel area if keying were done with the wrist bent.

You should try to vary your tasks. You should pause occasionally to give yourself a rest from repetitive tasks such as keying. This will give your body time to recover from stress and strain. (Please see discussion on varying tasks in the "Neck and Shoulder" section). Always use a gentle touch and not excessive force when keying.

Keyboards are designed to let you use a very light touch. You should develop your typing skills on the keyboard to consciously use as light a touch as possible.

You can also use arm and hand supports to help you maintain proper posture and work more comfortably. Arm rests can help take the weight off the shoulders and neck muscles thus reducing muscular fatigue. The same is true for your arm muscles. A padded wrist rest can provide a surface to rest your wrists and help you maintain proper keying postures.

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