Ergonomic Issues in the Courtroom Judicial Studies Board for Northern Ireland

Ergonomic Issues in Ergonomic Issues in the Courtroomthe Courtroom

Judicial Studies Board for Northern IrelandJudicial Studies Board for Northern Ireland

2929thth May 2007 May 2007

Dr Ken AddleyDr Ken AddleyDirector NICS OHSDirector NICS OHS

www.nicsohs.gov.ukwww.nicsohs.gov.uk

OutlineOutline

The back, posture, seats and sittingThe back, posture, seats and sitting

Computers and writingComputers and writing

Evolution – the Computer AgeEvolution – the Computer Age

The Vertebral ColumnThe Vertebral Column

General CharacteristicsGeneral Characteristics

Formed from 26 irregular bonesFormed from 26 irregular bones

Axial support of trunkAxial support of trunk

Surrounds and protects spinal cordSurrounds and protects spinal cord

Provides attachment points for ribs Provides attachment points for ribs and muscles of backand muscles of back

The Spine The Spine CervicalCervical is the neck area is the neck area

made up of 7 vertebrae made up of 7 vertebrae and curved inward or and curved inward or lordosislordosis

ThoracicThoracic is mid-back with is mid-back with 12 vertebrae and has 12 vertebrae and has outward curve or kyphosisoutward curve or kyphosis

LumbarLumbar area is lower back area is lower back with 5 vertebrae and is with 5 vertebrae and is curved inward or lordosiscurved inward or lordosis

SacrumSacrum is below lumbar is below lumbar and is solid mass of bone.and is solid mass of bone.

Anatomy: Soft TissuesAnatomy: Soft Tissues

NervesNerves branch off the spinal cord. branch off the spinal cord.

LigamentsLigaments are small, non-elastic bands are small, non-elastic bands that connect to the discs and vertebrae, that connect to the discs and vertebrae, lending support and stability to the spine.lending support and stability to the spine.

MusclesMuscles have strong attachments to the have strong attachments to the vertebrae along the entire length of the vertebrae along the entire length of the spine - strongest in their mid-range spine - strongest in their mid-range positionposition

Anatomy: Bones & DiscsAnatomy: Bones & Discs

Bony vertebrae; Bony vertebrae;

Facet Joints – 20% Facet Joints – 20% weightweight

Discs – 80% weightDiscs – 80% weight

L5

L4

L3

L2

L1

T12

T11

Spinal Cord

Intervertebral Disc

Vertebral Body

Back PainBack Pain

Low BackLow Back PainPain

• affects 7 out of 10 peopleaffects 7 out of 10 people

• commonest at age 35-55 yrscommonest at age 35-55 yrs

• 10 Million working days lost10 Million working days lost

• £481 million cost to NHS£481 million cost to NHS

• £5 billion cost to industry£5 billion cost to industry

Risk Factors for Back PainRisk Factors for Back Pain

Increase force/stressIncrease force/stress Repetitive Motion/twisting/Forward bendingRepetitive Motion/twisting/Forward bending Poor or improper lifting techniquesPoor or improper lifting techniques Poor posturePoor posture Poor Job designPoor Job design Deconditioned/Poor physical fitnessDeconditioned/Poor physical fitness OverweightOverweight Tall statureTall stature

Common Back ProblemsCommon Back Problems

Strains and sprainsStrains and sprains

Facet joint painFacet joint pain

Disc erosionDisc erosion

Sciatic nerve impingementSciatic nerve impingement

Herniated discsHerniated discs

Strains and SprainsStrains and Sprains

Commonest cause of Low Back PainCommonest cause of Low Back Pain

A pull on the soft muscle fibres causing A pull on the soft muscle fibres causing bruising inside the muscle.bruising inside the muscle.

Excessive pressure on the joints and those Excessive pressure on the joints and those ligaments attached to the joints.ligaments attached to the joints.

Symptoms - stiffness, pain & aching, loss Symptoms - stiffness, pain & aching, loss of mobility. of mobility.

Disc Problems (1)Disc Problems (1)

AcuteAcute - excessive and unusual stress and - excessive and unusual stress and strain forces on the back.strain forces on the back.

ChronicChronic - ageing, wear and tear and past - ageing, wear and tear and past injury (Degenerative Disc Disease):injury (Degenerative Disc Disease):

- - 35% Healthy Male Volunteers35% Healthy Male Volunteers

have significant DDD have significant DDD Paajenan et alPaajenan et al

-- 90% people age >50 have DDD 90% people age >50 have DDD Miller et alMiller et al

Disc Problems (2)Disc Problems (2)

Herniated / Bulging DiscHerniated / Bulging Disc

PosturePosture

Lumbar Disc Pressures Lumbar Disc Pressures

Mechanics: Poor PostureMechanics: Poor Posture

Spending long periods of time in abnormal Spending long periods of time in abnormal positions is stressful and damaging to the positions is stressful and damaging to the spine.spine.

With increased lumbar lordosis, facet joints With increased lumbar lordosis, facet joints are under increased pressure, nerve root are under increased pressure, nerve root spaces become smaller, and muscle and spaces become smaller, and muscle and ligaments are shortened.ligaments are shortened.

Means that the spine’s normal curves are Means that the spine’s normal curves are exaggerated or decreased creating stresses exaggerated or decreased creating stresses and strains in the tissues.and strains in the tissues.

Ideal PostureIdeal Posture

The ideal posture is governed by:The ideal posture is governed by:

The chairThe chair The taskThe task The personThe person Sitting habitsSitting habits

The ChairThe Chair

Low Back SupportLow Back Support

Chair HeightChair Height

Adjust or use foot restAdjust or use foot rest

Chair HeightChair Height

Feet flat on floorFeet flat on floor May need a foot May need a foot

restrest Thighs parallel to Thighs parallel to

the groundthe ground Or knees slightly Or knees slightly

lower than hipslower than hips

Seat Pan DepthSeat Pan Depth

Too Long: can cut off Too Long: can cut off circulationcirculation

Too Short: does not Too Short: does not provide enough provide enough supportsupport

IncorrectIncorrect

IncorrectIncorrect

Seat Pan DepthSeat Pan Depth

1-2 inches from 1-2 inches from back of knees to back of knees to

front of seatfront of seat

CorrectCorrect

Ankles TuckedAnkles Tucked

Leaning forwardLeaning forward

One size doesn’t fit everyone!One size doesn’t fit everyone!

Adjust the chair to suitAdjust the chair to suit

A Good Ergonomic ChairA Good Ergonomic Chair

Well-designed and adjustableWell-designed and adjustable

Provides support to the back, legs, buttocks Provides support to the back, legs, buttocks and arms, while reducing exposure to and arms, while reducing exposure to awkward postures, contact stress and awkward postures, contact stress and

forceful exertions.forceful exertions.

The TaskThe Task

The TaskThe Task

Not unduly repetitiveNot unduly repetitive No fixed, awkward or rigid posturesNo fixed, awkward or rigid postures Tolerable working environmentTolerable working environment Equipment ergonomically designedEquipment ergonomically designed Pace of work manageablePace of work manageable Adequate trainingAdequate training Task matched to the individualTask matched to the individual

The PersonThe Person

The PersonThe Person

Trained and competentTrained and competent Not anxious or tensedNot anxious or tensed Complies with safe system of workComplies with safe system of work Adjustment for disabilityAdjustment for disability Seek help, advice or guidanceSeek help, advice or guidance

SittingSitting

Pick the Better PosturePick the Better Posture

Sitting geometrySitting geometry

In unsupported chair (no back) In unsupported chair (no back) - the spine tends to flatten. - the spine tends to flatten.

With a lumbar support With a lumbar support - the spine tends to retain - the spine tends to retain its natural shape.its natural shape.

Sitting in a chair place your forearm in the Sitting in a chair place your forearm in the curve of your lower back and sit back in curve of your lower back and sit back in your seat this gives you an idea of a good your seat this gives you an idea of a good sitting posturesitting posture

Sitting & low back painSitting & low back pain

Some research shows a relationship Some research shows a relationship between low-back pain and prolonged between low-back pain and prolonged sitting. Others do not.sitting. Others do not.

Drivers who sit longer than 3.5 Drivers who sit longer than 3.5 hours/day have a 3x increase in risk of hours/day have a 3x increase in risk of disc herniation.disc herniation.

HSE recommends 15 min break per hour HSE recommends 15 min break per hour for computer operators.for computer operators.

Bad Posture: SittingBad Posture: Sitting

Slumping in chairs.Slumping in chairs. Sitting with legs folded to one side.Sitting with legs folded to one side. Sitting with ankles crossed.Sitting with ankles crossed. Slipping down the seat.Slipping down the seat. Persistently leaning forward.Persistently leaning forward. Sitting on edge of seatSitting on edge of seat

Prolonged sitting – Prolonged sitting –

do stretches throughout the do stretches throughout the day to keep your muscles day to keep your muscles flexible and avoid injury.flexible and avoid injury.

Computers & WritingComputers & Writing

The Digital CourtroomThe Digital Courtroom

VHS

DVD

Available ResourcesAvailable Resources

1. Document Camera

2. Touch Screen Annotator

3. Laptop Computer Video Hookup

1 2 3

4. Audio/Video playback5. Touch Screen Annotator

Ergonomically Correct Ergonomically Correct Work StationWork Station

Head LevelHead Level

Shoulders RelaxedShoulders Relaxed

Elbows at SidesElbows at SidesWrists straightWrists straight

Low Back SupportedLow Back Supported

Feet SupportedFeet Supported

Line of SightLine of Sight

Work Surface HeightWork Surface Height

Normal Working AreaNormal Working Area

Musculoskeletal Musculoskeletal ProblemsProblems

Musculoskeletal DisordersMusculoskeletal Disorders Common self-reported Common self-reported

work-related illnesswork-related illness

Major reason for seeking Major reason for seeking healthcarehealthcare

Major reason for work Major reason for work absenceabsence

- 10 million days/yr- 10 million days/yr- ave time off 18 days- ave time off 18 days

Mostly no objective Mostly no objective pathologypathology

Upper Limb Disorders Upper Limb Disorders (1)(1)

A variety of soft tissue injuries affecting A variety of soft tissue injuries affecting the muscles, tendons and nerves of the the muscles, tendons and nerves of the hands, arms, shoulders and neckhands, arms, shoulders and neck

If connected to work, also known as:If connected to work, also known as: Work related Upper Limb Disorder (WRULD)Work related Upper Limb Disorder (WRULD) Repetitive Strain Injury (RSI)Repetitive Strain Injury (RSI) Cumulative Trauma Disorder (CTD)Cumulative Trauma Disorder (CTD) Occupational Overuse Syndrome (OOS)Occupational Overuse Syndrome (OOS)

Carpel tunnel syndromeCarpel tunnel syndrome Cubital tunnel syndromeCubital tunnel syndrome Thoracic outlet syndromeThoracic outlet syndrome Raynaud’s syndrome (white Raynaud’s syndrome (white

finger)finger) Rotator cuff syndromeRotator cuff syndrome DeQuervain’s diseaseDeQuervain’s disease TendinitisTendinitis TenosynovitisTenosynovitis Trigger fingerTrigger finger Ganglion cystGanglion cyst


Historically thought to be caused by Historically thought to be caused by repetitive movements of hands or arms, repetitive movements of hands or arms, usually at speed and for prolonged periods usually at speed and for prolonged periods ("("dynamic loadingdynamic loading")")

Later, awkward/fixed postures ("Later, awkward/fixed postures ("static static loading")loading")

Importance of "Importance of "non-physicalnon-physical" factors " factors recently recognised by HSE.recently recognised by HSE.

Use of keyboards and mouse devicesUse of keyboards and mouse devices


Use of Keyboard and Mouse (1)Use of Keyboard and Mouse (1) Keep your fingers relaxed.Keep your fingers relaxed.

Use a soft touch on the keyboard instead of Use a soft touch on the keyboard instead of pounding keys with unnecessary force. pounding keys with unnecessary force.

Grasp the mouse gently – move using elbows Grasp the mouse gently – move using elbows not wrists. not wrists.

Avoid holding a pen or anything else in your Avoid holding a pen or anything else in your hands while you type or use the mouse. hands while you type or use the mouse.

Use of Keyboard and Mouse (2)Use of Keyboard and Mouse (2) Relax your fingers and hands between bursts of Relax your fingers and hands between bursts of

typing or mousing using a flat, neutral straight typing or mousing using a flat, neutral straight wrist posture. wrist posture.

Don't rest your elbows on hard surfaces.Don't rest your elbows on hard surfaces.

Use an Optical pick-up mouse.Use an Optical pick-up mouse.

Rest your eyes occasionally by focusing on Rest your eyes occasionally by focusing on distant objects. distant objects.

Writer’s CrampWriter’s Cramp

Diseases of Scribes and NotariesDiseases of Scribes and Notaries

““Incessant driving of the pen over paper causes intense fatigue Incessant driving of the pen over paper causes intense fatigue of the hand and the whole arm because of the continuous and of the hand and the whole arm because of the continuous and

almost tonic strain on the muscles and tendons, which in almost tonic strain on the muscles and tendons, which in course of time results in failure in the right hand.”course of time results in failure in the right hand.”

““Those who suffer most from these ailments are book-keepers Those who suffer most from these ailments are book-keepers and accountants, as they are called, for example those who and accountants, as they are called, for example those who

hire themselves to work for merchants. Also we must reckon in hire themselves to work for merchants. Also we must reckon in the same category the private secretaries of princes.”the same category the private secretaries of princes.”

““In winter they must take care not to let the hands grow numb In winter they must take care not to let the hands grow numb from excessive cold, so they must be protected by good thick from excessive cold, so they must be protected by good thick

gloves.”gloves.”

1713: Ramazzini: De Morbis Artificum Diatriba1713: Ramazzini: De Morbis Artificum Diatriba

Writer’s Cramp- Sir Richard Gower Writer’s Cramp- Sir Richard Gower 18931893

““The occurrence of the disease is influenced less by the The occurrence of the disease is influenced less by the amount than by the manner of writing. amount than by the manner of writing.

There are in writing two chief elements: the way in which the There are in writing two chief elements: the way in which the pen is held, and the way in which the movements are pen is held, and the way in which the movements are effected.”effected.”

He finds that he is grasping the pen too tightly, and He finds that he is grasping the pen too tightly, and cannot help doing so; taking a firmer hold seems to cannot help doing so; taking a firmer hold seems to increase the difficulty, and he finds that he writes slowly, increase the difficulty, and he finds that he writes slowly, as if a weight were attached to the hand. as if a weight were attached to the hand.

The hand feels strangely tired, and an aching pain in the The hand feels strangely tired, and an aching pain in the finger or thumb or first metacarpal bone, or in the wrist or finger or thumb or first metacarpal bone, or in the wrist or forearm, makes it still more difficult for him to go on forearm, makes it still more difficult for him to go on writing.writing.


Gowers recognised that lawyer’s clerks are especially affected by Gowers recognised that lawyer’s clerks are especially affected by reason of their cramped position. He described four methods of reason of their cramped position. He described four methods of writing:writing:

(1)(1) The hand resting on the little finger; movement of the pen byThe hand resting on the little finger; movement of the pen by the fingers and the thumb. the fingers and the thumb.

(2)(2) The hand resting on the wrist; lateral movement assisted byThe hand resting on the wrist; lateral movement assisted by the abductors of the wrist. the abductors of the wrist.

(3)(3) The middle of the forearm used as a fulcrum.The middle of the forearm used as a fulcrum.

(4)(4) The arm moved freely from the shoulder; the fingers The arm moved freely from the shoulder; the fingers scarcely move. scarcely move.

He found that cramp occurred especially in the first two groups; He found that cramp occurred especially in the first two groups; writers using the last method are immune.writers using the last method are immune.


The best and only free method is to write from the upper arm and The best and only free method is to write from the upper arm and shoulder, with no fixation of the arm; the forearm, wrist and little finger shoulder, with no fixation of the arm; the forearm, wrist and little finger rest on the table so as to take some of the weight of the limb from the rest on the table so as to take some of the weight of the limb from the shoulder-muscles, but both wrist and forearm move along the table as shoulder-muscles, but both wrist and forearm move along the table as the writing progresses from left to right. the writing progresses from left to right.

In this way the pen can be held lightly; very little of the movement is In this way the pen can be held lightly; very little of the movement is effected by the small muscles of the hand; the fingers scarcely alter effected by the small muscles of the hand; the fingers scarcely alter their position, except when a stroke is carried far above or below the their position, except when a stroke is carried far above or below the line; and even for this a movement of the fingers is not always line; and even for this a movement of the fingers is not always necessary. necessary.


Summary – Computers & WritingSummary – Computers & Writing

Ensure desk surface at correct height – Ensure desk surface at correct height – adjust chair if necessaryadjust chair if necessary

Use mouse correctly – optical pick-upUse mouse correctly – optical pick-up Don’t grip pen too tightlyDon’t grip pen too tightly Don’t use a thin penDon’t use a thin pen Don’t hold a fixed posture – avoid hoveringDon’t hold a fixed posture – avoid hovering Take time to stretch when away from the Take time to stretch when away from the

deskdesk

Summary - SittingSummary - Sitting

Choose your seat carefully and adjust to Choose your seat carefully and adjust to suitsuit

Don’t slumpDon’t slump Don’t cross your legs or anklesDon’t cross your legs or ankles Don’t adopt fixed posturesDon’t adopt fixed postures Take time to stretch when away from the Take time to stretch when away from the

deskdesk

Northern Ireland Civil ServiceNorthern Ireland Civil Service

Occupational Health ServiceOccupational Health Service

NICS Centre for Workplace Health ImprovementNICS Centre for Workplace Health Improvement

Lincoln BuildingLincoln Building

27-45 Great Victoria Street27-45 Great Victoria Street

Belfast BT2 7SHBelfast BT2 7SH

Website: www.nicsohs.gov.ukWebsite: www.nicsohs.gov.uk

Documents

Ergonomic Issues in the Courtroom Judicial Studies Board for Northern Ireland