The document discusses various types of ergonomic injuries and musculoskeletal disorders that can result from unsatisfactory working conditions. It describes injuries related to lifting and handling, such as those caused by asymmetric lifting or lifting weights outside recommended limits. It also discusses work-related upper limb disorders (WRULDs) such as cumulative trauma disorders (CTDs) and repetitive strain injuries (RSIs) that often affect the upper limbs and are related to high intensity and duration of work. Specific disorders mentioned include carpal tunnel syndrome, lateral epicondylitis, and thoracic outlet syndrome. The document emphasizes that many ergonomic injuries can be predicted and prevented by addressing risk factors like extreme postures, high forces, repetitive motions, vibration, temperature

1. Ergonomics
WRULD and musculoskeletal disorders
Loisa Sessman, Halmstad University

2. Health and safety
 Accidents
 Unsafe behavior
 Unsafe systems
 Everyday accidents
 Slipping, tripping & falling
 Machinery – safety distance
 Ergonomic injuries
 Lifting and handling injuries
 Work-related upper limb disorders
 Musculoskeletal pain resulting from unsatisfactory
working posture
Loisa Sessman, Halmstad University

3. Ergonomic injuries
 Mismatch
 Over-use injury
 “Creep” effect (fatigue)
 Mechanical strength
 Co-ordination
 Range of motion
 Foreseeable, injuries can be predicted!
 Back pain
 Occupational
 Personal risk factors
Loisa Sessman, Halmstad University

4. Lifting and handling
 Lift close to the body
 Reduce the lever arm
 Control
 Symmetric
 Avoid asymmetric lifting
 Foot placement
 Weight limits
 Different limits for different countries
 Sweden, 7 kg = ok, 7-25 kg = risky 25 kg = very
high risk
Loisa Sessman, Halmstad University

5. Work-related upper limb disorders
 WRULD
 Umbrella term for CTD and RSI
 Repetitive strain injury (RSI)
 Cumulative trauma disorders CTD
 Mainly affects:
 Industrial assembly workers
 Workers at supermarket checkouts
 Musicians
 Keyboard users
Loisa Sessman, Halmstad University

6. RSI & CTD
 Often occurs in the upper limb
 Injuries in nerves, muscles, ligaments, tendons
and joints etc
 Causes pain
 Related to work intensity and duration
 Weeks, months or years
 Diffuse symptoms
 Often unreported
 Several reasons (work and/or leisure time)
Loisa Sessman, Halmstad University

7. RSI & CTD
 CTD & RSI increases
 Increased awareness and reporting
 Increased specialization
 Computer work
 Mental stress
 Posture
 Force
 Repetition
Loisa Sessman, Halmstad University

8. Postures
 Extreme flexion and extension, ulnar and radial
deviation of the hand
 Carpal Tunnel Syndrome
 Tenosynovitis
 Extreme flexion of the elbow
 Cubital Tunnel Syndrome
 Extreme rotation of the forearm
 Epicondylitis
 Work above shoulder level
 Thoracic Outlet Syndrome
Loisa Sessman, Halmstad University

9. Carpal Tunnel Syndrome
 Results from high repetitive work in extreme
positions, often in combinations with force
 Median nerve get squeezed
 Numbness, tingling pain and clumsiness
Loisa Sessman, Halmstad University

10. Tenosynovitis
 Tendon sheath swells
 Occurs at wrists and ankles where tendons cross
ligaments
 Pain, burning sensation and swelling
Loisa Sessman, Halmstad University

11. Cubital Tunnel Syndrome
 Compression of the ulnar nerve in the elbow
 Tingling and numbness occurs at the little finger
and the ulnar side of the ring finger
 Causes when resting the elbow on a hard surface
or sharp edge
Loisa Sessman, Halmstad University

12. Epicondylitis
 Lateral epicondylitis – De
Quervain's disease (tennis elbow) Lateral epicondylitis
 Injuries and pain resulting from
work with computer mouse
 Causes of high repetitive finger
Medial
movements in combination with epicondylitis
static work Tendon
 The symptoms: pain in the forearm Muscle
and weakness in the hand and
wrist
 Medial epicondylitis – golfer’s arm http://www.orthoactiv.de/index.php?open=peripherenerven
 Similar to tennis elbow
 Affects the medial epicondyle of
the humerus
Loisa Sessman, Halmstad University

13. Tendonitis or tendinitis
 Inflammation of a tendon
 Pain, swelling, burning sensation
 Tendonitis or bursitis at the rotator cuff
 Unnatural static positions
 Heavy work
 External load
 Repetitive arm movements
 Work above shoulder height
Loisa Sessman, Halmstad University

14. Thoracic outlet syndrome
 Compression of three nerves of the arm and blood
vessels
 Numbness
 Difficult to move the arm
Loisa Sessman, Halmstad University

15. Contact stress
 Mechanical stress (contact stress) on nerves and
tendons
 Handhold objects with sharp edges and hard objects
 Vibrating tools - Raynauds syndrom (white fingers)
 Reducing contact stress
 Change posture
 Use gloves
 Use design-friendly tools
 Use grip surfaces that are smooth, non conductive
of cold or heat and anti-slip
Loisa Sessman, Halmstad University

16. Repetition
 High repetitive work require more muscle effort
 The muscles need more time to recover
 Vary postures can reduce repetitive movements
Loisa Sessman, Halmstad University

17. Other causes
 Temperature
 Cold
• Blood circulation
• Time for recovery
 Heat
• Sweat – slip
 Vibration
 Blood circulation
 Require greater grip force
 Try to isolate the vibrations!
Loisa Sessman, Halmstad University

18. Conclusion
There are several musculoskeletal disorders caused
by extreme postures, forces, high repetitive work.
Also hand-tools and environmenment
can cause injuries.
Loisa Sessman, Halmstad University