Work-related musculoskeletal disorders (WMSDs) are injuries to muscles, ligaments, tendons, nerves, and blood vessels caused by repetitive motions that occur often and over a long period of time. Usually the arms and hands are the affected areas, but WMSDs can occur in the legs as well. Carpal tunnel syndrome is one of the most common work-related musculoskeletal disorders, and is caused by swollen tendons in the wrist compressing the medial nerve in the hand. The range of WMSDs grouped together is also termed repetitive motion injuries, cumulative trauma disorders, overuse syndrome, and soft tissue disorders.
A repetitive strain injury can occur when tendons become inflamed. This happens when there is not enough lubrication produced within tendon sheaths. The resulting friction causes the swelling, and over time tendon motion can be restricted if fibrous tissue forms around it. When a tendon sheath swells up, it is called tenosynovitis, while bursitis is tendon swelling in the shoulder that occurs within the bursa, where the tendon passes through the bones.
Work-related musculoskeletal disorders also include nerve compression, caused by the swelling of tissues around the nerves. A range of symptoms can result from this including muscle weakness, numbness, and pins and needles sensations. Tendons can swell up in the wrist, the elbow, and in the shoulder, resulting in pain, weakness, and swelling at the affected location of the body. Repetitive load carrying tasks which require someone to hold their arms above the shoulders, or carry loads on the shoulder, lead to swelling in the hands, and general pain and numbness. This is called thoracic outlet syndrome.
In nearly all cases, work-related musculoskeletal disorders result from performing repetitive tasks that by themselves do not cause injury, but the pace of the work does not allow muscles and tendons to recover before the task is carried out again. Restricted posture puts a strain on the neck, leading to a condition known as tension neck syndrome. Hot and humid conditions, as well as cold temperatures, increase the risk of injury. Another risk factor is vibration, which can cause numbness in the fingers over time, and can result from the use of automated tools.
Work-related musculoskeletal disorders can be treated by restricting movement, applying heat or cold, stretching, or sometimes medication and surgery. The only ways to prevent them are to change workplace practices, structure the workplace layout to avoid strain on the body, and to use proper tools. If there is suspicion of a work-related disorder, a physician should be consulted.