2. Objectives
By the end of this class final year should
able to know:
What is cumulative trauma disorder?
Causes of cumulative trauma disorders
Common WMSD’s
3. Cumulative Trauma Disorders
Cumulative = occurring gradually over a
period of weeks, months, or years
Trauma = bodily injury to nerves, tissues,
tendons, or joints
Disorders = physical ailments or abnormal
conditions
4. Cumulative Trauma Disorders
Bodily injuries or physical ailments
that have developed gradually over
periods of weeks, months, or even
years as the result of repeated stresses
on a particular body part
5. What are aliases for WMSDs?
Work-related MSDs go by many other names:
– Repetitive Strain or Stress Injury (RSI)
– Repetitive Motion Injury (RMI)
– Cumulative Trauma Disorder (CTD)
– Overuse Syndrome
– Activity-related Pain Syndrome
6. Causes of CTD’s
Usually caused by a combination of following
risk factors:
Repetitive motions
Forceful exertions - pulling, pushing, lifting,
and gripping
Awkward postures
Static postures - body positions held
without moving
7. Causes of CTD’s
Mechanical compression of soft tissues in the
hand against edges or ridges
Fast movement of body parts
Vibration especially in the presence of cold
conditions
Mental stress
Lack of sufficient recovery time (rest breaks,
days off)
9. Common CTD’s
Lower Body
– Low Back Pain
– Back Strain
– Disc Disorder
– Degenerative Disc Disorders
– Sciatica
– Knee Disorders
– Foot Disorders
10. Clinical symptoms of MSDs
• Continuous general
weakness
• Restrictions of movements
• Sleep disturbances
• Other physical &
psychological problems
• Discomfort continues
• Sleep disturbances
• Limitation of work
• Pain
• Tiredness
• Numbness
• Tingling
• Discomfort
• Stiffness in joints
• Weakness
• Swelling
• Burning
• Loss of functions
11. A FEW SOLUTIONS...
Reduce manual material handling
– Pre-Plan material drops
– Utilize material handling equipment
– Keep materials in “neutral zone”
Equipment
– Use the right tool for the job
– Evaluate new tools for ergonomics
– Keep sharp & in good repair
– Use vibration dampening tools / gloves
Reduce Duration
– Mini-breaks
– Multi-task
– Employee rotation/job share
12. Common CTD’s
Carpal Tunnel Syndrome-Injury to
the median nerve.
Tendonitis-Swelling of the tendons.
Tenosynovitis-Swelling in tendon
sheath.
13. Carpal Tunnel Syndrome
Definition
– Compression neuropathy of the median nerve at
the wrist
Palmar
aponeurosis
Median nerve
14. Carpal Tunnel Syndrome
Pain and Paresthesias on palmar-radial
aspect of hand
Often worse at night
Risk factors
– Intrinsic
– extrinsic
15. Carpal Tunnel Syndrome
Intrinsic risk factors
– Anatomic variants
» Either decreased dimension of carpal tunnel or
increased volume of its contents
– Physiologic variants
» Diabetes , alcoholism , smoking , pregnancy ,
rheumatoid arthritis , myxedema
» All associated with edema
16. Carpal Tunnel Syndrome
Extrinsic factors
– Hand position
– Forceful use of hand
– Repetitive motion
– Vibration
17. Carpal Tunnel Syndrome
MRI has shown that wrist flexion
compresses the median nerve between
flexor retinaculum and tendons
Minimizing wrist flexion/extension by
redesign of tools helps reduce CTS
18. Carpal Tunnel Syndrome
Forceful use of hand
Repetitive motion is a risk factor for hand
pain BUT not specifically for CTS
No correlation between hours of keyboard
work and CTS
19. Carpal Tunnel Syndrome
and Vibration
Hand-arm vibration syndrome
– Raynaud’s , sensory changes
– Digital nerves mainly
– Often misdiagnosed as CTS
Definite dose-response relationship
– >50% incidence with >8000 hrs.
Carpal tunnel release does not help
20. Dequervain’s Tendonitis
Tendon entrapment not tenosynovitis
Analogous to trigger finger
APL & EPB tendons
Peritendinous fibrosis not inflammation
22. Dequervain’s Tendonitis
No reports that relate incidence of
Dequervain’s to frequency or intensity of
repetitive work
Tender over radial styloid
Finklestein’s test
31. Impingement syndrome
• Repetitive overhead use of arm
• Swimmers,pitchers
• painful arc
• impingement signs
• decreased ROM active vs. passive
• pain with resisted motion
34. Warning Signs
Numbness and tingling in first three fingers
Clumsy feeling in your hand
Pain going up into the elbow or shoulder
Pain is worse at night
36. Alternative Work Methods
Evaluate Work Area
Take Periodic rests
and Stretch
Awkward positions
caused by certain
items and work
practices in can be
prevented.
Trying to do too much
at one time can cause
muscles to tire and
cause injury
37. Environment Adjustment
Replace Existing Equipment-The desks
should have rounded edges to reduce
possible pressure points. The chairs need
the arm height and chair height to be
adjustable, and give back support by having
a tilt adjustment.
38. Environment Adjustment
Add Accessories to Existing Equipment-
Wrist rests- help to promote a neutral wrist
position
An adjustable document holder - promote the
proper head angle
A seat cushion- helps to support the back
A footrest- helps to keep thighs parallel to the
ground and promote good posture
39. Education, New Equipment and
Preventative Measures
All Add Up To A Safer and
Ergonomically Correct Work
Environment
