The Definition of Musculoskeletal Disorder (MSD)

Definition of Musculoskeletal Disorder (MSD)

A musculoskeletal disorder (MSD) is an injury or condition that affects the muscles, tendons, ligaments, nerves, joints, cartilage or spinal discs. Work-related MSDs develop when the body is exposed to physical stress, such as repetitive motion, forceful exertion, awkward postures or vibration, faster than it can recover. They can also result from a single sudden strain.

MSDs are one of the most common causes of lost work time and workers' compensation costs worldwide. Common examples include low back pain and strains, carpal tunnel syndrome, tendinitis, rotator cuff injuries, trigger finger, epicondylitis (tennis elbow) and hand-arm vibration syndrome.

OSHA does not have a specific ergonomics standard in the United States, but it can cite employers under the General Duty Clause for serious ergonomic hazards, and work-related MSDs must be recorded if they meet OSHA recordkeeping criteria. In the UK, the Manual Handling Operations Regulations and Display Screen Equipment Regulations address MSD risks, and Australian WHS laws cover hazardous manual tasks.

Risk Factors for MSDs

Work-related factors

• Repetition: doing the same motion many times with little rest, such as assembly line work or scanning items.
• Force: lifting, pushing, pulling or gripping heavy or awkward loads. See overexertion.
• Awkward postures: bending, twisting, reaching overhead or kneeling for long periods.
• Static postures: holding the same position for a long time, such as standing at a workstation or sitting at a desk.
• Contact stress: pressure from hard edges or tool handles against the body.
• Vibration: using vibrating hand tools or sitting on vibrating vehicles.
• Cold: working in cold environments, which reduces dexterity and blood flow.

Organizational and personal factors

Fast work pace, long shifts, too few rest breaks, high job stress and poor training all raise MSD risk. Individual factors such as fitness, age and previous injuries can also play a part, but the focus should be on fixing the work, not the worker.

Preventing MSDs

• Assess tasks: use ergonomics assessments to find high-risk tasks and measure lifting, posture and repetition.
• Engineer out the risk: use lift assists, conveyors, adjustable workstations, carts and better-designed tools.
• Redesign work: reduce load weights, bring items into the comfortable reach zone and avoid lifting from the floor or above the shoulders.
• Administrative controls: add rest breaks, use job rotation and set realistic production rates.
• Training: teach safe manual handling and kinetic lifting techniques as a backup to design changes.
• Early reporting: encourage workers to report pain or discomfort early, when MSDs are easier to treat.

Example of Musculoskeletal Disorder

At a distribution center, several order pickers reported wrist and shoulder pain after the site increased its pick rate targets. Two workers were diagnosed with tendinitis and one with carpal tunnel syndrome.

An ergonomics assessment found that pickers were reaching to the back of deep, high shelves and twisting to place items in totes on the floor. The site moved fast-moving items to waist-height locations, raised tote stands, added short micro-breaks and rotated workers between picking and packing. New MSD reports dropped over the next six months.

Frequently Asked Questions: Musculoskeletal Disorder

What are the most common work-related MSDs?

Back injuries, carpal tunnel syndrome, tendinitis and shoulder injuries are among the most common.

Are MSDs OSHA recordable?

A work-related MSD is recordable if it meets OSHA's general recording criteria, such as days away from work, restricted work or medical treatment beyond first aid. See recordable incident.

How can office workers prevent MSDs?

Office workers can reduce risk with a properly adjusted chair, desk and monitor, a neutral wrist position, regular breaks and changing posture throughout the day.