Musculoskeletal disorders

Ergonomics

WRULD and musculoskeletal disorders

Loisa Sessman, Halmstad University

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


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


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


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


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)


RSI & CTD

CTD & RSI increases Increased awareness and reporting Increased specialization Computer work Mental stress

Posture

Force

Repetition


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


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


Tenosynovitis

Tendon sheath swells

Occurs at wrists and ankles where tendons cross ligaments

Pain, burning sensation and swelling


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


Epicondylitis Lateral epicondylitis – De

Quervain's disease (tennis elbow) Injuries and pain resulting from

work with computer mouse Causes of high repetitive finger

movements in combination with static work

The symptoms: pain in the forearm and weakness in the hand and wrist

Medial epicondylitis – golfer’s arm Similar to tennis elbow Affects the medial epicondyle of

the humerus

MuscleTendon

Medial epicondylitis

Lateral epicondylitis

http://www.orthoactiv.de/index.php?open=peripherenerven


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


Thoracic outlet syndrome

Compression of three nerves of the arm and blood vessels Numbness Difficult to move the arm


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


Repetition

High repetitive work require more muscle effort The muscles need more time to recover

Vary postures can reduce repetitive movements


Other causes

Temperature Cold

• Blood circulation• Time for recovery

Heat• Sweat – slip

Vibration Blood circulation Require greater grip force Try to isolate the vibrations!


Conclusion

There are several musculoskeletal disorders caused by extreme postures, forces, high repetitive work.

Also hand-tools and environmenment can cause injuries.


Musculoskeletal disorders

Education

Transcript of Musculoskeletal disorders