Safety Ergonomics
Safety 4000
UCMO
Safety Ergonomics
• Outline
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Industries Affected
History of Ergonomics
Future of Ergonomics
Overall Health effects
Lab Computer Workstation
Evaluation of Hand tools
Health effects of tools
Final Examination and Practical
Safety 4000, Ergonomics
August 2008
Class Work
• Practical Examination – workstation
evaluation
• Paper: Proposed Ergonomics standard
• Quizes
• Final Examination
Safety 4000, Ergonomics
August 2008
Paper
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Suggested criteria/standard on ergonomics
Specific Tool/process
Follow OSHA Example
Present or discuss your paper in class
If you bring the tool, it’s worth extra credit.
Safety 4000, Ergonomics
August 2008
Paper Requirements
• 5-7 pages minimim
• 3 References (NIOSH, CDC, OSHA)
– Extra credit for additional references
• Provide analysis
• Industry Cost $$$$
• How many injuries will this standard prevent
Safety 4000, Ergonomics
August 2008
Paper Due:
• 11 October 2008.
• Advantage in early paper turn-in.
• Comments?
Safety 4000, Ergonomics
August 2008
Practical
• Perform an evaluation of Computer
Workstation
• Complete form
• Provide Recommendations
Safety 4000, Ergonomics
August 2008
Final
• About 25 Questions
–Multiple-choice questions
–Fill in the blank
–3-4 Essay Questions
–True/False
Safety 4000, Ergonomics
August 2008
Media*
• Videos on Ergonomic Programs
• Material is testable
Safety 4000, Ergonomics
August 2008
Texts:
• The Ergonomics Edge: Dan Macleod.
• Practical Ergonomics
Safety 4000, Ergonomics
August 2008
Ergonomics
• You’re Experience?
Safety 4000, Ergonomics
August 2008
Questions?
Safety 4000, Ergonomics
August 2008
What Is Ergonomics?
Fall 2006
SAFE4000 Overview
13
Ergonomics
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Based on 2 words, ergo & nomos
Ergo means laws or rules
Nomos means work or strength
Thus, ergonomics means laws of
work
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
14
Ergonomics
• 1950, “ergonomics” was coined by a
group of British scientists
• 1957 American Scientists working in
the same discipline called
themselves the Human Factors
Society
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
15
Ergonomics Is ...
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Engineering Tool
Design out job hazards
Eliminating causes
Preventing accidents
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
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Viewpoints on Ergonomics
• Historic viewpoint - make people
fit the job, e.g., “The Jungle”
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
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Viewpoints on Ergonomics
• Current Viewpoint - make job fit the
person
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
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Ergonomic Definitions
• Board of Certification in Professional
Ergonomics
–Body of knowledge about human
abilities, human limitations, and other
human characteristics that are relevant
to design
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
19
Ergonomic Definitions
• OSHA
–Study of the design of requirements of
work in relation to the physical and
psychological capabilities and
limitations of people
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
20
Keywords - FAR*LTV
• Force
• Awkward posture
• Repetition
{*3 most important risk factors}
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
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Keywords - FARLTV (continued)
• Lack of Rest
• Temperature
• Vibration
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
22
Body Tissues Affected
• Soft Tissues
–Nerves
–Tendons
–Tendon Sheaths
–Ligaments
–Blood vessels
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
23
Body Tissues Affected
• Bones
–Spine, especially the lower portion of
spine – lumbar region
–Bones in fingers - white finger disease
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
24
Is Ergonomic a New
Problem?
Fall 2006
SAFE4000 Overview
25
History - Bernardo Ramazzini
–In 1700 this Italian physician
wrote a text describing many
occupational hazards
–Included were problems that
today we call cumulative trauma
disorders (CTDs)
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
26
History - Bernardo Ramazzini
–CTDs appeared in workers who
did violent & irregular motions
and assumed unnatural positions
–Also noted problem for office
workers!
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
27
History - Bernardo Ramazzini
• He noted risk factors for office
workers:
–Repetitive hand motions
–Constrained postures
–Excessive mental stress
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
28
Early Tools…
Dental Tools!
Safety 4000, Ergonomics
August 2008
History - Alice Hamilton
• Dr. Alice Hamilton
–Mother of Occup Medicine in US
–Studied White Finger Disease (HAVS) in
Indiana Limestone Quarry workers in
the 1930’s
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
30
History - Erwin Tichauer
• Dr. Tichauer
– Taught at New York University
– Developed concept of bending tool
handle instead of the worker’s wrist
– Wrote Chapter 32 of the NIOSH White
Book, 1973
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
31
Bend Tool Handle - Not Wrist
Fall 2006
SAFE4000 Overview
32
John Deer, 1837 Plow
Common Terms
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Washer Woman’s Sprain
Gamekeepers Thumb
Telegraphist’s Cramp
Writer’s Cramp
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
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Safety 4000, Ergonomics
August 2008
Common Terms
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Trigger Finger
Tennis Elbow
Golfer’s Elbow
Dunlaps Disease
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
37
Benefits of Improving Ergonomic
Environment
• Higher morale
• Improved quality of work
• Greater efficiency/Improved
productivity
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
38
Benefits of Improving Ergonomic
Environment
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Reduced absenteeism
Lower turnover
Fewer repetitive trauma disorders
Fewer workers comp claims
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
39
Certification - Continued
• BCPE - Board of Certification in
Professional Ergonomics
– First certifications in 1992
– CPE/CHFP
– More recently developed
Associates Certification
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
40
Ergonomics Focuses On
• Accommodating information processing
capabilities of the brain
• Physical properties/constraints of body
• Designing controls to minimize muscle
fatigue
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
41
Ergonomics Consists Of
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Engineering
Physiology
Medicine
Anthropometrics
Behavioral Science
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
42
Other Ergonomic Considerations
• Psychological factors (attitudes)
• Somatic factors (age)
• Physiological factors (glucose,
oxygen)
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
43
Other Ergonomic Considerations
• Learning factors (knowledge)
• Nature of work (intensity, duration)
• Environment (heat, chemical
exposure, noise)
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
44
Ergonomists Use A Systems
Approach
Applying Systems Approach
• Proactive - action taken before CTD
occurs
• Reactive - corrective action taken
after CTD occurs
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
46
No two workers are identical
• Equal height
–different arm reach
–different trunk height
• Equal weight
–different strengths
–different heights
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
47
No two workers are identical
• Design a workstation to
accommodate 90-95% of the
working population
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
48
Design Considerations
• Control/display design &
location
• Location/orient. of work
surface
• Guarding/warnings
• Posture
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
49
Design Considerations
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Movements/repetitions
Accessibility
Machinery/equipment design
Hand tool design
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
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Design Considerations
• Size/shape of work objects
• Weight of work
objects/equipment
• Vibration
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
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Amount of Physical Stress
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Force needed or weight handled
Load location or posture
Task repetition
Duration of task
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
52
Ergonomic Factors For Worker
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Does employee stand or sit?
Is employee stationary or mobile?
Does job require great strength?
Can reaching be done
comfortably?
• Are job tasks repetitive?
Safety 4000, Ergonomics
August 2008
53
Ergonomic Factors For Worker
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Control over pace of work?
Tools properly fitted?
Proper PPE used?
Job environment
uncomfortable?
• Job boring to worker?
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
54
Anthropometry
The study of the physical
dimensions of the various parts
of the human body (size, range
of motion)
Anthropometry
• Military has large sets of
anthropometric data
• More recently surveys of civilian
populations have been conducted
• In early part of 21st Century, US
Airforce initiated a large civilian
anthropometric survey
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
56
Anthropometry
• Ethnic differences can be
significant:
–North American males height ~1,790
mm
–Southern India males height ~1,620
mm
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
57
How Big Is The Problem?
• DOL (1982):
–Back injuries were one of the most
common & costly WRI
–back injuries ~20 % of Inj./Ill.
–1/4 of workers comp payments
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
58
How Big Is The Problem?
• National Safety Council (1990)
–overexertion accounted for 31% of
all injuries
–Back most frequently injured
–22% of 1.7 million injuries
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
59
How Big Is The Problem?
Current estimates are that
1/2 of workers comp claims
are ergonomic-based
Fall 2006
SAFE4000 Overview
60
How Big Are The Bucks ($)
• 1997 NIOSH - workers comp costs at
13 billion
• 1999 NIOSH - associated costs are
between 50-100 billion
• 1999 OSHA Basically agrees with the
NIOSH estimated costs
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
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Is this big bucks?
YES!
Fall 2006
SAFE4000 Overview
62
Identifying Problem Areas
• Review records
• Walk through survey - spend time
observing jobs
• Analyze input from established to
find problems
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
63
Record Review
• CTD/back overexertion injuries
• Determine trends
• Identify factors for additional
analysis
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
64
Worksite Analysis
• Categories
– Dept, job, shift, time, weekday, etc.
– Type of injury, body part involved
– Instrument of injury (e.g., bin #, machine
#)
– Job experience, age of worker, gender,
supervisor
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
65
Indicators of Ergonomic
Problems
• Work accidents are obvious indicators
of ergonomic problems.
• Other less obvious indicators exist
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
66
Less-Obvious Indicators of Ergonomic
Problems
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Trends in accidents/injuries
Absenteeism, high turnover rate
Seasonal hiring pattern
Employee complaints
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
67
Less-Obvious Indicators of Ergonomic
Problems
• Employee-generated workplace
changes
• Incentive pay systems
• Excessive overtime
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
68
Less-Obvious Indicators of Ergonomic
Problems
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Increased work rate
Poor product quality
Manual material handling
Repetitive motion tasks
Improperly designed workstations
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
69
Employee Generated Changes
• Added padding to tools or work
surfaces
• Altered seats and/or chairs
• Makeshift platforms
• Gets help to complete task
• Modification of PPE
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
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Employee Generated Changes
• Shiny work surfaces
– from contact with workers body
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Changed workflow design
Modified illumination
Modified ventilation
Realigned tools, fixtures, or staging areas
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
71
Common CTDs
• Carpal Tunnel Syndrome burning, tingling, itching in
wrist or first 3 fingers & thumb
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
72
Common CTDs
• Epicondylitis - (tennis elbow)
inflammation of tissues on
thumb side of elbow
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
73
Common CTDs
• Hand Arm Vibration Syndrome
(White Finger Disease) numbness, pain, blanching of
fingers, loss of muscle
strength, sensitive to heat &
cold
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
74
Common CTDs
• Thoracic Outlet Syndrome &
Bursitis & Rotator Cuff Syndrome
–affects nerves & muscles of upper
arms & shoulders
–Associated with overhead work
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
75
American with Disabilities Act
Requires that feasible
ergonomic accommodation for
accessibility & adaptation to an
individual’s particular disability
be made to the workstation &
surrounding areas
Fall 2006
SAFE4000 Overview
76
When Should You Identify
Ergonomic Problems?
• The sooner the better!
• Incorporate ergonomic
principles into design stage!
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
77
References
• Jim McGlothlin. Chapter 28 - Ergonomics. In:
The Occupational Environment - Its Evaluation,
Control & Management, AIHA 2003
• Tichauer ER. Ergonomic Aspects of
Biomechanics. In: The Industrial Environment Its Evaluation & Control. NIOSH. 3rd Edition
1973. (Produced via contract by George D.
Clayton & Associates)
• Kroemer, KHE. Ergonomics. Chapter 13. In
Fundamentals of Industrial Hygiene. Barbara
Plog, Editor. National Safety Council. 2002
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
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References
• Ergonomics - A Practical Guide, 2nd Edition, National
Safety Council, 1993.
• Fitting the Task To The Human. Kroemer Grandjean,
5th Edition, 1997
• Words Of Wisdom & Personal Communication with
Dr. Marvin Mills, Retired Ergonomic Professor.
Lexington, KY.
Safety 4000, Ergonomics
Fall 2006
August 2008
SAFE4000 Overview
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History…
• Ramazinni: 1633-1714
• Wrote about work related complaints
• Wojciech Jastrzebowski: Created the word
Ergonomics in 1857
Safety 4000, Ergonomics
August 2008
Ergonomics…
• What is it?
• Basic Confusion on Meaning
• Different Definitions
Safety 4000, Ergonomics
August 2008
Ergonomics
• Similar to Industrial Engineering
• Similar to Human Factors Engineering
– Computer Users
– Meat Packers
– Assembly line personnel
– Nurses
– Packagers
– Construction
– Agriculture
Safety 4000, Ergonomics
August 2008
History…
• Ergonomics
• Ergo - Work
• Nomos - law
Safety 4000, Ergonomics
August 2008
Frank Gilbreth
• Efficiency and Time-Motion Studies
Safety 4000, Ergonomics
August 2008
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Safety 4000, Ergonomics
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Early Pioneers
• Frederick Taylor
Safety 4000, Ergonomics
August 2008
1_BricklayingErgonomics.flv
Safety 4000, Ergonomics
August 2008
Workplace Changes - WWII
• What effect?
• Who was in workplace?
• How was equipment designed?
Safety 4000, Ergonomics
August 2008
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Workplace Adjustments
• Ergonomics – Adjusting Workplace to worker
Safety 4000, Ergonomics
August 2008
Industries
• Food Cashiers:
Safety 4000, Ergonomics
August 2008
Extent of Problem
•600,000 Each Year (MSD)
•30% of Construction Events
•$200 Billion to Fix (estimates)
•$10K per person medical
treatment
OSHA
• New OSHA Standard
• 1910.900 (Died)
• ANSI A10.40-2700
Safety 4000, Ergonomics
August 2008
The Result?
• Type Injuries
• (Muscularskeletal Disorders, MSD)
Safety 4000, Ergonomics
August 2008
MSD
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Carpal Tunnel Syndrone
Back injury (Lumbar)
Shower (rotator cuff bursititis)
Washer Knee
Safety 4000, Ergonomics
August 2008
Medical Effects:
Safety 4000, Ergonomics
August 2008
Construction…
Safety 4000, Ergonomics
August 2008
Work Related
Musculoskeletal Disorders
Upper Extremity Disorders
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Carpel tunnel syndrome
Cubital tunnel syndrome
Thoracic outlet syndrome
Raynaud’s syndrome (white finger)
Rotator cuff syndrome
DeQuervain’s disease
Tendinitis
Tenosynovitis
Trigger finger
Ganglion cyst
Neurovascular Disorders
• Carpal Tunnel Syndrome
– Impingement of the median nerve caused by irritation
and swelling of the tendons in the carpal tunnel
• Cubital Tunnel Syndrome
– Pressure on the ulnar nerve when the elbows are
exposed to hard surfaces
Safety 4000, Ergonomics
August 2008
Neurovascular Disorders
• Thoracic Outlet Syndrome
– Compression of the blood vessels between the neck and
shoulder caused by reaching above shoulder level or
carrying heavy objects
• Raynaud’s Syndrome
– Also known as Vibration White Finger ; Blood vessels of
the hand are damaged (narrowed) from repeated
exposure to vibration for long periods of time
Safety 4000, Ergonomics
August 2008
Tendon Disorders
• Rotator Cuff Syndrome
• DeQuervain’s Disease
– Combination of tendinitis and tenosynovitis
• Tendinitis
– Irritation of the tendon
• Tenosynovitis
– Irritation of the synovial sheath
• Ganglion Cyst
Safety 4000,
Ergonomics
August 2008
– Accumulation
of fluid within
the tendon
sheaths
Tendinitis
Safety 4000, Ergonomics
August 2008
Hand and Wrist
Safety 4000, Ergonomics
August 2008
Common Occupational CTDs
of the Upper Extremities
Carpal Tunnel Syndrome occurs from chronic
swelling of the flexor tendons in the wrist.
The median nerve, which feeds the first three fingers
and the thumb, can become impaired from pressure in
the carpal tunnel in the wrist.
Symptoms include:
 pain in the first three fingers and the thumb
 numbness in these areas
 tingling in these areas
Carpal Tunnel Syndrome
Carpal Tunnel Syndrome
Common Occupational CTDs
of the Upper Extremities
Raynaud’s Syndrome is when blood vessels of the
hand are damaged (narrowed) from repeated exposure
to vibration for long periods of time
This is connected with use of vibrating tools, such as
hair clippers and jack hammers.
Raynaud’s Syndrome
Symptoms
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Numbness and tingling in the fingers during vibration exposure;
may continue after exposure has been discontinued
Blanching (whitening) of one fingertip because of a temporary
constriction of blood flow
Other fingers also blanch
Intensity of pain & frequency of attacks increase in time
Common Occupational CTDs
of the Upper Extremities
Cubital Tunnel Syndrome is caused by resting
the elbows on hard surfaces such as unpadded
tables or armrests.
The ulnar nerve, which feeds the ring and little
fingers, can become impaired from pressure near the
elbows.
Symptoms include:
 pain in the ring and little fingers
 tingling in these areas
 numbness in these areas
Cubital Tunnel Syndrome
Common Occupational CTDs
of the Upper Extremities
Thoracic Outlet Syndrome is caused by frequent reaching
above shoulder level, by carrying heavy objects, or poor posture
involving a forward head tilt.
A Neurovascular bundle called the brachial plexus, which passes
between the collar bone and the top rib, can become impaired from
pressure associated with movements that causes these two bones to
be positioned close together.
Symptoms include:
 the arms “falling asleep”
 weakened pulse
 numbness in the fingers
Thoracic Outlet Syndrome
Common Occupational CTDs
of the Upper Extremities
Rotator cuff syndrome is a disorder involving swelling and pain
of tendons comprising the rotator cuff muscle group:
subscapularis, supraspinatus, infraspinatus, & teres minor
Symptoms include:
• Pain when you bend the arm and rotate it outwards against resistance
• Pain on the outside of the shoulder possibly radiating down into the arm
• Pain in the shoulder, which is worse at night
• Stiffness in the shoulder joint.
Rotator Cuff Syndrome
Anterior View
Posterior View
Common Occupational CTDs
of the Upper Extremities
Tendinitis is a common CTD for the wrist, elbow, and
shoulder. It occurs when we continually stress the
tendon cables, causing them to become irritable and
sore.
Lateral Epicondylitis - “Tennis elbow”
Medial Epicondylitis - “Golfer’s elbow”
Symptoms include:
 point tenderness
 swelling
 tennis elbow, pain radiates down to back of hand
 golfer’s elbow, pain radiates down to back of hand
Tendinitis
Common Occupational CTDs
of the Upper Extremities
Tenosynovitis is swelling of the sheath
that covers the tendon from constant
rubbing against the tendon.
Symptoms include:
swelling
pain
loss of motion
loss of strength
Tenosynovitis
Common Occupational CTDs
of the Upper Extremities
Trigger Finger is a tendon
disorder that occurs when there is
a groove in the flexing tendon of
the finger
If the tendon becomes locked in
the sheath, attempts to move the
finger cause snapping or jerking
movements
Usually associated with using
tools that have handles with hard
or sharp edges.
Trigger Finger
Safety 4000, Ergonomics
August 2008
Common Occupational CTDs
of the Upper Extremities
Ganglion Cyst is a bump under the skin caused
by an accumulation of fluid within the tendon
sheath. It is commonly found at the hand and
wrist.
Safety 4000, Ergonomics
August 2008
Ganglion Cyst
Safety 4000, Ergonomics
August 2008
Common Occupational CTDs
of the Upper Extremities
De Quervain’s Disease is an inflammation of the
tendon sheath of the thumb attributed to excessive friction
between two thumb tendons and their common sheath.
It’s a combination of Tendonitis and Tenosynovitis.
May be caused by twisting and forceful gripping
Symptoms include:
•swelling
•pain at the base of the thumb.
De Quervain’s Disease
De Quervain’s Disease
Prospective Study of Computer Users
Fredric Gerr, et. al., 2002, “A Prospective Study of
Computer Users: 1. Study Design and Incidence of
Musculoskeletal Symptoms and Disorders”.
– 632 individuals
– Newly hired into jobs requiring  15 hr/week of
computer use
– Were followed for up to 3 years
Safety 4000, Ergonomics
August 2008
Primary Results
• Hand/Arm (H/A) & Neck/Shoulder (N/S) MSS and MSD
were common among computer users
• More than 50% of users reported MSS during the 1st
year after starting a new job
• Most common H/A disorder was DeQuervain’s tendonitis
• Most common N/S disorder was somatic pain syndrome
Safety 4000, Ergonomics
August 2008
Common Occupational Injuries
of the Back
Strains and sprains are damage to the tendons and
ligaments caused by one time exertions such as lifting or
carrying heavy objects.
These can lead to very noticeable back pain, but the pain
usually begins to subside within a few days
Common Occupational CTDs
of the Back
Facet joint pain results from irritation of the area
where the ribs meet the spinal column.
Typically, there is muscle swelling in the affected area
and it can become very painful to sit or stand up
straight. In some cases it may also be difficult to breath
deeply.
Safety 4000, Ergonomics
August 2008
Common Occupational CTDs
of the Back
Disk erosion occurs from prolonged pressure on the
spinal disks, which causes them to become permanently
compressed.
The space between the vertebrae becomes smaller, which
can lead to impingement of the nerve roots leading out
from the spine.
Sitting puts more pressure on the spinal disks than
standing, and sitting with the back unsupported can lead
to high levels of disk pressure.
Disc Erosion
Common Occupational CTDs
of the Back
Sciatic nerve impingement, also called sciatica, is
common for people who sit for prolonged periods of time.
The sciatic nerve runs from your lower back down the
back of your leg and into to your feet.
Swelling in certain muscles in the buttocks can put
pressure on the sciatic nerve, causing pain down the leg.
Common Occupational CTDs
of the Back
Herniated discs occur when the inner portion of the disc
protrudes, putting pressure on the nerve roots leading
from the spine.
Pain or numbness in the legs is a common symptom of
herniated discs in the lower back.
Safety 4000, Ergonomics
August 2008
Herniated/Bulging Disc
Break