Anatomy and Ergonomic Interactions
With the Human Body

Medical Management of
Ergonomically-Related Disorders

Ergonomic Disorders
Muscle Strains and Sprains
Cumulative Trauma Disorders
Muscle Problems
Tendon Problems
Nerve Problems
Diagnosis and Evaluation
Treatment
Policy Statement: Preventive Devices

Ergonomic Disorders
Ergonomic disorders are conditions of the musculo-skeletal and/or nervous systems in either the upper or lower extremities, including the lower back. These conditions typically become problematic for an individual when they create pain, numbness, or restrict a bodily motion. Ergonomic disorders may be caused or aggravated by repetitive motions, forceful exertions, vibration, sustained or awkward positioning of the body, or mechanical compression of the hands, wrists, arms, back, neck shoulders, or legs over extended periods of time.

Muscle Strains and Sprains
Muscle strains and sprains are the most common ergonomically-related conditions. These can occur from over-exertion or repeated motions. Common symptoms include muscle fatigue and pain in the shoulders, neck, wrists, and lower back.

Cumulative Trauma Disorders
Cumulative trauma disorders (CTDs) are defined as disorders of the muscles, tendons, or nerves caused by repeated mechanical stress to a particular part of the body – most commonly the hands, wrists, arms, or shoulders. Research has shown that the contributing factors tend to be the amount of force exerted, frequency of the repetitive motion, sustained posture, nerve compression, and insufficient rest or recovery time. CTDs are not new to medicine – tennis elbow, writer’s cramp, telegraphist’s cramp, cotton-twister’s hand, stitcher’s wrist, and bricklayer’s elbow are just some of the CTDs familiar to health-care professionals. Whether or not the condition is work or non-work related is often difficult to ascertain since activities such as weekend sports, carpentry, gardening, playing an instrument, or sewing can predispose employees to CTDs.

CTDs can be categorized by the physiologic group of the body affected. Some examples include:

Muscle Problems
Myalgia (general term for muscle pain)
Myofacial pain syndrome (irritation of the membrane surrounding muscle)

Tendon Problems
Tendonitis (irritation of a tendon, often accompanied by pain)
Tenosynovitis (irritation of the sheath surrounding a tendon)
Dequervain’s disease (tenosynovitis at base of thumb)
Epicondylitis (irritation of the tendon attachments at the elbow, i.e., tennis elbow, golfer’s elbow)
Trigger finger (a type of extreme tenosynovitis leading to locked fingers)

Nerve Problems
Carpal Tunnel Syndrome (damage to the median nerve passing through the wrist area)
Guyon’s Canal Syndrome (damage to another of the three nerves passing through wrist)
Cubital Tunnel Syndrome (damage to a nerve passing through elbow)
Thoracic Outlet Syndrome (compression of the nerves and blood vessels between neck and shoulder)
Hypothenar Hammer Syndrome (nerve damage from repeated impacts at base of palm)

Diagnosis and Evaluation
of Ergonomically-Related Conditions
Because many types of conditions fall under the category of ergonomically-related disorders and injuries, their symptoms and diagnosis are different. Some typical symptoms include persistent pain in a functionally-affected area of the body, tingling and numbness, or a feeling of heat in the affected area. Symptoms usually occur while performing the activity and may persist into resting times, often becoming more intense during the night. If you are experiencing symptoms which you believe are related to your work, contact the Employee Health Office (432-0071) for a medical evaluation, and the Office of Environmental Health & Safety for a job task assessment (785-3550).

Treatment
Like diagnosis, treatment of ergonomically-related conditions depends upon the severity and duration of the condition, as well as modification of the source of the problem. Early diagnosis and treatment is more effective than later treatment. Mild cases of most cumulative trauma disorders, when detected early, can be successfully treated with anti-inflammatory drugs, rest or restricted activities, and, in certain cases, physical therapy. More severe cases often require prolonged rest, anti-inflammatory drugs, immobilizing splints or supports, heat or ice treatments, and physical therapy. Surgery is sometimes also indicated in a very small fraction of severe cases, but should be considered only after all other options have been explored.

Policy Statement: Preventive Use of Wrist Supports, Back Belts, and Related Devices
Many people inquire about the use of wrist braces, arm or elbow braces, and back belts as a way to prevent various ergonomically-related disorders. These kinds of inquiries have become more numerous as public awareness of ergonomics has increased, and as organizations and corporations address ergonomics for their staff. The widespread use of so-called “back belts” at several home supply companies has also contributed to such inquiries.

Although all of these kinds of devices can provide relief in the treatment of ergonomically-related conditions, the scientific evidence to date on their preventive use has been inconclusive at best. Back belts do provide support to the back, but require proper use and unfortunately cause many users to erroneously believe they can now lift heavier or more awkward objects. Recent physiologic testing data also indicate that back belts merely redistribute the force of the lifted load onto other, often weaker, muscle groups of the body, leading to injuries elsewhere. Similarly, the routine use of wrist supports or braces during keyboarding restricts motion of the hands, can reduce blood flow and pinch nerves, and ultimately redirects forces from the wrist to the forearm.

Various types of splints, supports, and braces can play an important part in physical rehabilitation by restricting ergonomically-poor motions or isolating affected musculo-skeletal elements. This is important in severe cases of carpal tunnel syndrome, where the wrist needs to remain straight during recovery, especially during sleeping hours when many people tend to curl their wrists.

Given the inconclusive nature of the available data to date, coupled with the potential harm that can be caused by their indiscriminant use, requests for these kinds of devices must be evaluated by a medical expert and an assessment of the work task(s) performed.

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Medical Issues
Exercises and Stretching