Ergonomic Issues in the Courtroom Judicial Studies Board for Northern Ireland

1. Ergonomic Issues in the CourtroomJudicial Studies Board for Northern Ireland 29th May 2007 Dr Ken Addley Director NICS OHS www.nicsohs.gov.uk

2. Outline • The back, posture, seats and sitting • Computers and writing

3. Evolution – the Computer Age

4. The Vertebral Column

5. General Characteristics • Formed from 26 irregular bones • Axial support of trunk • Surrounds and protects spinal cord • Provides attachment points for ribs and muscles of back

6. The Spine • Cervical is the neck area made up of 7 vertebrae and curved inward or lordosis • Thoracic is mid-back with 12 vertebrae and has outward curve or kyphosis • Lumbar area is lower back with 5 vertebrae and is curved inward or lordosis • Sacrum is below lumbar and is solid mass of bone.

7. Anatomy: Soft Tissues • Nerves branch off the spinal cord. • Ligaments are small, non-elastic bands that connect to the discs and vertebrae, lending support and stability to the spine. • Muscles have strong attachments to the vertebrae along the entire length of the spine - strongest in their mid-range position

8. Anatomy: Bones & Discs • Bony vertebrae; • Facet Joints – 20% weight • Discs – 80% weight

9. T11 T12 Vertebral Body L1 L2 Spinal Cord L3 L4 Intervertebral Disc L5

10. Back Pain

11. Low BackPain • affects 7 out of 10 people • commonest at age 35-55 yrs • 10 Million working days lost • £481 million cost to NHS • £5 billion cost to industry

12. Risk Factors for Back Pain • Increase force/stress • Repetitive Motion/twisting/Forward bending • Poor or improper lifting techniques • Poor posture • Poor Job design • Deconditioned/Poor physical fitness • Overweight • Tall stature

13. Common Back Problems • Strains and sprains • Facet joint pain • Disc erosion • Sciatic nerve impingement • Herniated discs

14. Strains and Sprains • Commonest cause of Low Back Pain • A pull on the soft muscle fibres causing bruising inside the muscle. • Excessive pressure on the joints and those ligaments attached to the joints. • Symptoms - stiffness, pain & aching, loss of mobility.

15. Disc Problems (1) • Acute - excessive and unusual stress and strain forces on the back. • Chronic - ageing, wear and tear and past injury (Degenerative Disc Disease): - 35% Healthy Male Volunteers have significant DDDPaajenan et al- 90% people age >50 have DDDMiller et al

16. Disc Problems (2) Herniated / Bulging Disc

17. Posture

18. Lumbar Disc Pressures

19. Mechanics: Poor Posture • Spending long periods of time in abnormal positions is stressful and damaging to the spine. • With increased lumbar lordosis, facet joints are under increased pressure, nerve root spaces become smaller, and muscle and ligaments are shortened. • Means that the spine’s normal curves are exaggerated or decreased creating stresses and strains in the tissues.

20. Ideal Posture The ideal posture is governed by: • The chair • The task • The person • Sitting habits

21. The Chair

22. Low Back Support

23. Chair Height Adjust or use foot rest

24. Chair Height • Feet flat on floor • May need a foot rest • Thighs parallel to the ground • Or knees slightly lower than hips

25. Seat Pan Depth Incorrect Too Long: can cut off circulation Incorrect Too Short: does not provide enough support

26. Seat Pan Depth 1-2 inches from back of knees to front of seat Correct

27. Ankles Tucked

28. Leaning forward

29. One size doesn’t fit everyone!

30. Adjust the chair to suit

31. A Good Ergonomic Chair Well-designed and adjustable Provides support to the back, legs, buttocks and arms, while reducing exposure to awkward postures, contact stress and forceful exertions.

32. The Task

33. The Task • Not unduly repetitive • No fixed, awkward or rigid postures • Tolerable working environment • Equipment ergonomically designed • Pace of work manageable • Adequate training • Task matched to the individual

34. The Person

35. The Person • Trained and competent • Not anxious or tensed • Complies with safe system of work • Adjustment for disability • Seek help, advice or guidance

36. Sitting

37. Pick the Better Posture

38. Sitting geometry • In unsupported chair (no back) - the spine tends to flatten. • With a lumbar support - the spine tends to retain its natural shape. • Sitting in a chair place your forearm in the curve of your lower back and sit back in your seat this gives you an idea of a good sitting posture

39. Sitting & low back pain • Some research shows a relationship between low-back pain and prolonged sitting. Others do not. • Drivers who sit longer than 3.5 hours/day have a 3x increase in risk of disc herniation. • HSE recommends 15 min break per hour for computer operators.

40. Bad Posture: Sitting • Slumping in chairs. • Sitting with legs folded to one side. • Sitting with ankles crossed. • Slipping down the seat. • Persistently leaning forward. • Sitting on edge of seat

41. Prolonged sitting – do stretches throughout the day to keep your muscles flexible and avoid injury.

42. Computers & Writing

43. The Digital Courtroom

44. 1 2 3 Available Resources 1. Document Camera 2. Touch Screen Annotator 3. Laptop Computer Video Hookup • Audio/Video playback • Touch Screen Annotator

45. Ergonomically Correct Work Station Head Level Line of Sight Shoulders Relaxed Elbows at Sides Wrists straight Low Back Supported Feet Supported

46. Work Surface Height

47. Normal Working Area

48. Musculoskeletal Problems

49. Common self-reported work-related illness Major reason for seeking healthcare Major reason for work absence- 10 million days/yr- ave time off 18 days Mostly no objective pathology Musculoskeletal Disorders

50. Upper Limb Disorders (1) • A variety of soft tissue injuries affecting the muscles, tendons and nerves of the hands, arms, shoulders and neck • If connected to work, also known as: • Work related Upper Limb Disorder (WRULD) • Repetitive Strain Injury (RSI) • Cumulative Trauma Disorder (CTD) • Occupational Overuse Syndrome (OOS)