Musculoskeletal Health

6.1 Work-Related Upper Limb Disorders

What musculoskeletal disorders and work-related upper limb disorders are

Musculoskeletal disorders (MSDs) are injuries and disorders that affect the body's movement system: the muscles, tendons, ligaments, nerves, discs and related tissues.

• Upper limb disorders (ULDs) include aches and pains in the shoulders, arms, wrists, hands and fingers, and also in the neck.
• Lower limb disorders (LLDs) can affect the hip, thigh, knee, calf, ankle or foot.

Employers must protect workers from the risk of developing both kinds of disorder at work.

Upper limb disorders are more common in tasks that involve:

• prolonged repetitive work, especially using the same hand or arm action
• uncomfortable or awkward working postures
• sustained or excessive force
• doing a task for a long time without suitable rest breaks
• using hand-held power tools for long periods

Lower limb disorders are more common in tasks that involve:

• repeated kneeling or squatting
• climbing stairs or ladders
• heavy manual handling
• prolonged standing

Other factors can influence both kinds:

• a poor working environment, including temperature and lighting
• poor work organisation, including workload, job demands and lack of breaks
• individual differences and vulnerability, because some workers are more affected by certain risks

A worker is more likely to develop upper limb problems when there is more than one risk factor in the work. Symptoms in the upper limbs can include aches and pains, tenderness, weakness, tingling, numbness, cramp, burning, redness and swelling, stiffness, and pain or reduced movement in the joints.

Ill-health conditions that poorly designed tasks and workstations can cause

Several disorders can affect the upper limbs.

• Carpal tunnel syndrome (CTS). Damage to a nerve that runs through the wrist into the hand. It comes from repeatedly bending the wrist while gripping tools tightly, or from constantly pressing the wrist against a hard object, and it occurs mainly because of repetitive wrist movements. Symptoms include pain, numbness, tingling, burning sensations, wasting of the muscles at the base of the thumb, and a dry palm.
• Tendonitis or tenosynovitis. Inflammation and soreness of a tendon, the thick fibrous cord that joins muscle to bone, caused by repeated movement of a joint. It gives pain and tenderness just outside a joint. It can occur in any tendon but is most common around the shoulders, elbows, wrists, knees and heels. Causes include repetitive wrist or shoulder movements, sustained hyperextension of the arms and prolonged load on the shoulders. Symptoms include pain, weakness, swelling, a burning sensation or a dull ache over the affected area.
• Osteoarthritis. Breakdown of the protective cartilage on the ends of bones, causing pain, swelling and difficulty moving the joint. Bony growths may form and the area may become red. Some people also notice tenderness and a grating or crackling sound when the joint moves. Causes may include age, overuse of joints, and excess strain on joints, particularly those that bear most of the body's weight, such as the knees and hips.
• Hand-arm vibration syndrome (HAVS). Hand-arm vibration comes from using hand-held power tools and causes significant ill health, including painful and disabling disorders of the blood vessels, nerves and joints.
• Vibration white finger. A vascular effect of hand-arm vibration involving attacks of finger blanching, often triggered by cold. Numbness and tingling can also reflect nerve damage; do not wait for white fingers before reporting symptoms.
• Thoracic outlet syndrome. Reduced blood flow in the shoulder and arm, caused by working above head height or by carrying heavy loads in the hands with the arms hanging straight down. It can result from prolonged shoulder flexion, working with the arms above shoulder height and carrying loads on the shoulder. Symptoms include pain, numbness and swelling of the hands.

Lower limb disorders with evidence linking them to work include:

• Osteoarthritis. A degenerative condition of the joints, such as hips and knees. Farmers have a higher risk of hip osteoarthritis, and floor layers and cleaners have a higher risk of knee osteoarthritis.
• Knee bursitis. Caused by repeated kneeling. It brings tenderness, swelling and reduced knee movement.
• Knee meniscal (cartilage) lesions or tears. If the knee is bent or twisted while bearing a load, the force may damage the meniscus. Overuse, such as repeated squatting or kneeling, is also linked with damage, which can lead on to osteoarthritis.
• Stress fracture. Caused by repeated micro-injuries to bone. More common in the armed forces and in athletes, particularly long-distance runners.
• Varicose veins. Dilated veins of the leg. Workers may complain of heaviness and pain, swollen legs, night-time calf cramps and restless legs. They are linked with prolonged standing and heavy lifting.

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