ERGONOMICS

Ergonomics can be defined simply as the study of work. More specifically, ergonomics is the science of designing the job to fit the worker, rather than physically forcing the worker’s body to fit the job.

Parts of the Body Affected by MSDs
• Arms         • Back
• Hands        • Wrists
• Fingers      • Legs
• Neck         • Shoulders

MSD Risk Factors
• Force
• Repetition
• Awkward postures
• Static postures
• Quick motions
• Compression or contact stress
• Vibration

• Cold temperatures

What types of work are most likely to pose ergonomic hazards?
MSDs affect workers in almost every occupation and industry in the nation and in workplaces of all sizes. The disorders occur
most frequently in jobs that involve:
•Manual handling,
•Manufacturing and production,
•Heavy lifting,
•Twisting movements, and
•Long hours of working in awkward positions.

Top Ten Occupations for MSDs
• Nurses aides, orderlies, and attendants
• Laborers not involved in construction work
• Assemblers
• Truck Drivers & Janitors and cleaners
• Registered nurses
• Stock handlers 
• Construction laborers
• Cashiers

• Carpenters

A Simple Case Study

An Uplifting Solution
Problem: At a glass ceramic cooktop plant, workers manually lift uncut plates of glass onto a waist-high conveyor belt, where it is then stacked vertically on a nearby L-shaped holder. A forklift
handles the strapped holder carrying the glass. The holder, however, presents the glass at knee-height, making workers
bend each time to pick up the glass.

Solution: The workers devised a stand made from a wooden shipping crate and placed it beneath the L-holder to raise the glass to waist height.


Cost: A little labor.

Glossary & Definitions

Anthropometry - The study of human body measurements. Used in developing design standards and requirements for manufactured
products to ensure they are suitable for the intended audience.

Biomechanics - A scientific and engineering field that explains the charateristics of biological system–the human body–in mechanical
terms. 

Carpal tunnel syndrome - The compression and entrapment of the median nerve where it passes through the wrist into the hand—in the carpal tunnel. The median nerve is the main nerve that extends down the arm to the hand and provides the sense of touch in the thumb, index finger, middle finger, and half of the fourth, or ring, finger. 

De Quervain’s disease - Inflammation of the tendon sheath of the thumb attributed to excessive friction between two thumb tendons
and their common sheath. Usually caused by twisting and forceful gripping motions with the hands.

Industrial hygiene - The science of anticipating, recognizing, evaluating, and controlling workplace conditions that may cause worker injuries and illnesses.

Kinesiology - Study of the principles of mechanics and anatomy in relation to human movement.

Musculoskeletal disorders - Injuries and disorders of the soft tissues (muscles, tendons, ligaments, joints, and cartilage) and nervous

system.

Raynaud’s syndrome, or white finger - Blood vessels of the hand are damaged from repeated exposure to vibration long period of
time. The skin and muscles do not get the necessary oxygen from the blood and eventually die. Symptoms include intermittent numbness and tingling in the fingers; pale, ashen, and cold skin; eventual loss of sensation and control in the hands and fingers.

Tendinitis - Tendon inflammation occurring when a muscle or tendon is repeatedly tensed from overuse or unaccustomed use of the wrist and shoulder.

Tenosynovitis - Inflammation or injury to the synovial sheath surrounding the tendon. Usually results from repetition excessive repetitive motion.

Trigger finger - 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 an jerking movements. Usually associated with using tools that have handles with hard or sharp edges.