Upper Body Risk Factors

RMI risk factors are conditions that increase the risk of developing RMI. As with known risk factors for heart disease, such as a high fat diet or lack of physical activity, exposure to RMI risk factors does not automatically lead to impaired health. Rather, these risk factors have been shown to increase the likelihood that an RMI may occur.

There are several factors that can increase the probability of developing an RMI. The more factors that are involved and the greater the exposure to each, the higher the likelihood of developing an RMI. The primary RMI risk factors are:

Force — forceful exertions that do not cause harm with one motion, but which can build up micro-trauma over time. For example, holding unnecessary force in your thumb and fingers or using excessive force while keying and mousing are RMI risk factors.

Frequency — too much repetition or too little movement can contribute to micro-trauma. For example, highly repetitive mousing motions are RMI risk factors as is prolonged sitting without taking a break to stand or change position.

Posture — there are certain postures in which we are more susceptible to injury, especially at the extremes of our range of motion. For example, cradling the phone between the shoulder and neck or reaching to an input device located in a poor position are RMI risk factors.

There are also personal risk factors that contribute to the likelihood of developing an RMI. These include obesity, lack of exercise, diseases such as hypertension and diabetes, and the regular use of oral contraceptives, alcohol or cigarettes.

Typical RMIs Associated with Computer Use

Tendons connect muscles to bones. When we contract muscles in our forearms (the movers), the tendons (cables) pull on the bones (levers) in our hands to create movement. These movement mechanics apply to other areas of the body as well.

Typical tendon disorders:

Tendonitis is a common RMI of the wrist, elbow and shoulder. It occurs when we continually stress the tendon cables, causing them to become irritable and sore. Symptoms of tendonitis include:

Tenosynovitis is swelling of the sheath that covers the tendon resulting from constant rubbing against the tendon. Symptoms include:

De Quarvain's Disease is a combination of tendonitis and tenosynovitis. Symptoms include swelling and pain at the base of the thumb.

Ganglion Cyst is a bump under the skin caused by an accumulation of fluid within the tendon sheath. It is commonly found at the hand and wrist.

Nerves are the highly specialized tissues that transfer information from the senses (touch, sight, etc.) to the brain and transfer commands from the brain to the body. When swelling in the connective tissues such as tendons puts pressure on the nerves, movement can become impaired, and pain and numbness can occur.

Typical nerve disorders include:

Carpal Tunnel Syndrome occurs from chronic swelling of the flexor tendons near the wrist. The median nerve, which feeds the first three fingers and the thumb, can become impaired from pressure in the carpal tunnel in the wrist. Symptoms include:

Cubital Tunnel Syndrome is caused by resting the elbows on hard surfaces such as an unpadded table or armrests. The ulnar nerve, which feeds the ring and little fingers, can become impaired from pressure near the elbows. Symptoms include:

Neurovascular disorders are illnesses that affect both nerves and nearby blood vessels. The affected area of the body can receive reduced circulation, resulting in less oxygen and nutrients to the muscles.

Thoracic Outlet Syndrome is caused by frequent reaching above shoulder level, carrying heavy objects or poor posture involving a forward head tilt. A neurovascular bundle called the brachial plexus, which passes between the collar bone and the top rib, can become impaired from pressure associated with movements that cause these two bones to be positioned close together. Symptoms include: