CIEE Repetitive Motion & CTD Prevention 4 — Questions and Answers
Question 1: A meatpacking plant ergonomist wants to prioritize workstations for CTD intervention. Which tool is MOST appropriate for a rapid, systematic screening across 50 jobs?
- REBA (Rapid Entire Body Assessment)
- OSHA 300 log review combined with BRIEF survey (Correct answer)
- NIOSH lifting equation
- Electromyography (EMG) analysis
Correct answer: OSHA 300 log review combined with BRIEF survey
The BRIEF (Baseline Risk Identification of Ergonomic Factors) survey is designed for rapid workplace screening and pairs well with injury records to prioritize high-risk jobs efficiently.
Question 2: Cumulative trauma disorder (CTD) risk increases when work pace is externally controlled (machine-paced). The MAIN ergonomic concern is:
- Workers cannot adjust tool grip strength
- Workers have no opportunity to self-regulate recovery and rest (Correct answer)
- Machine vibration transfers to the upper extremity
- Ambient lighting fluctuates with production speed
Correct answer: Workers have no opportunity to self-regulate recovery and rest
Machine-paced work removes the worker's ability to insert self-determined micro-pauses, eliminating spontaneous recovery periods that reduce cumulative tissue load.
Question 3: Thoracic outlet syndrome (TOS) in overhead workers primarily involves compression of which structures?
- Radial nerve and brachial artery at the cubital tunnel
- Brachial plexus and subclavian vessels between the clavicle and first rib (Correct answer)
- Median nerve at the pronator teres muscle
- Ulnar nerve at the olecranon groove
Correct answer: Brachial plexus and subclavian vessels between the clavicle and first rib
TOS results from compression of the brachial plexus and subclavian neurovascular bundle in the thoracic outlet space between the clavicle, first rib, and scalene muscles.
Question 4: Which ergonomic principle explains why tool handles should be designed for a grip span of approximately 2.5–3.5 inches (6–9 cm)?
- This range maximizes vibration dampening properties of the hand
- This span allows maximum grip force generation with minimal tendon strain (Correct answer)
- This range matches ISO power tool weight standards
- This span eliminates the need for anti-vibration gloves
Correct answer: This span allows maximum grip force generation with minimal tendon strain
A grip span of 6–9 cm aligns the finger flexors near their optimal length-tension relationship, generating maximum grip force while minimizing internal tendon stress.
Question 5: A worker's symptoms improve on weekends but return each Monday. This symptom pattern is MOST diagnostic of:
- A pre-existing degenerative joint condition unrelated to work
- A work-related CTD with insufficient recovery between exposures (Correct answer)
- Psychosomatic disorder triggered by work-week stress
- Acute traumatic injury sustained on the prior Friday
Correct answer: A work-related CTD with insufficient recovery between exposures
Weekend relief followed by Monday recurrence is a classic sign of work-related cumulative trauma where two days of rest allow partial recovery, confirming occupational causation.
Question 6: In vibration-exposed workers, Raynaud's phenomenon secondary to hand-arm vibration (HAV) is also called:
- Carpal tunnel syndrome stage III
- Vibration white finger (VWF) (Correct answer)
- Dupuytren's contracture
- Hypothenar hammer syndrome
Correct answer: Vibration white finger (VWF)
Vibration white finger (VWF), also classified under hand-arm vibration syndrome (HAVS), describes blanching/color changes in the fingers caused by vasospasm from chronic HAV exposure.
Question 7: According to the hierarchy of controls, which intervention represents the highest-order control for preventing repetitive motion CTDs?
- Mandatory stretching program before each shift
- Personal protective equipment such as anti-vibration gloves
- Redesigning the process to eliminate the repetitive task through automation (Correct answer)
- Job rotation between equally repetitive tasks
Correct answer: Redesigning the process to eliminate the repetitive task through automation
Elimination or substitution (e.g., automating the repetitive task) sits at the top of the hierarchy of controls and is most effective because it removes the hazard entirely.
CIEE Repetitive Motion & CTD Prevention 4
A meatpacking plant ergonomist wants to prioritize workstations for CTD intervention.
Which tool is MOST appropriate for a rapid, systematic screening across 50 jobs?