09_musculoskeletal_risks_and_controls_20140117153117

Question 1

Different joints allow different ranges of movement, as explained below, and also shown in Figure 9.3.

Answer 1

(a) Gliding joints, between the ribs and thoracic vertebrae, for example, allow bones to move or slide past each other. (b) Hinge joints, such as the knee and elbow, allow movements which alter the angle in one plane between two articulating bones. (c) Pivot joints, such as the axis and atlas in the neck, allow rotation. The elbow is also articulated between the radius and ulna to allow the lower arm to be twisted. (d) Ellipsoid joints, such as the wrist, are similar to ball and socket, but have less movement. (e) Saddle joints allow for back and forth or up and down movement, but no rotation. The thumb is the only example of a saddle joint. (f) Ball and socket joints, such as the hip, allow movement in all directions (including rotation). This occurs as the ball-shaped end of one bone (the femur) moves within a cup-shaped cavity of another (the pelvic girdle).

Question 2

First class levers have the fulcrum in the middle. The effort and resistance are applied at opposite ends. An example is

Answer 2

the movement of the skull on the spinal column.

Question 3

Second class levers possess the fulcrum at one end and the resistance in the middle. The effort is applied at the other end. An example is

Answer 3

seen when raising the body on the toes.

Question 4

Third class levers are the commonest type in the body. The fulcrum is at one end of the lever and the resistance at the other end. The effort is applied to the middle. An example is

Answer 4

the flexion of the forearm.

Question 5

Biomechanics applies the physical laws of mechanics to the human body, enabling estimation of the local mechanical stress on muscles and joints arising from adopting a posture or making a movement. Some important considerations are 8

Answer 5

Joints must be in a neutral position The work should be kept close to the body Bending forward should be avoided Twisting the trunk should be avoided Peak stresses are produced by sudden movementsPostures should be varied, as well as movementsThe duration of continuous muscular effort should be limited Short frequent breaks are better than longer infrequent breaks

Question 6

Physiological studies permit estimates to be made of the energy demands on the heart and lungs resulting from muscular effort during movements, considering both localised fatigue from continuous localized muscular effort and general body fatigue from carrying out physical tasks over a prolonged period. Important principles include: 2

Answer 6

Limiting the energy expenditure in a task Resting after heavy tasks

Question 7

Anthropometry is the study of the size and proportions of the human body. Anthropometric principles of importance to the ergonomics of posture and movements include: 2

Answer 7

 Taking account of differences in body size when designing workstations, workplaces and accessories etc.  Using anthropometric tables that are appropriate for the specific population.

Question 8

The causes of WRULDs are not clear, but key risk factors are: 7

Answer 8

 repetitive work  uncomfortable working postures  sustained or excessive force  carrying out a task for a long period of time  poor working environment (example: temperature and lighting)  poor work organisation (example: work pressure, job demands, work breaks or lack of them)  individual differences and susceptibility (some workers are more affected by certain risks).

Question 9

Tendonitis (fingers/hand/forearm)

Answer 9

Inflammation of the tendon.

Question 10

Tenosynovitis

Answer 10

Inflammation of the tenosynovium (tendon sheath) and tendon.

Question 11

De Quervain’s

Answer 11

Tenosynovitis affecting thumb tendons.

Question 12

Trigger finger

Answer 12

A stenosing tenosynovitis, locking a finger in either a bent or straight position Note: Stenosing is the narrowing of the tendon sheath.

Question 13

Carpal tunnel syndrome

Answer 13

Tendonitis or tenosynovitis of the tendon passing through the carpal tunnel compresses the median nerve, affecting sensation on the palm side fingers and thumb.

Question 14

Shoulder capsulitis (frozen shoulder)

Answer 14

Inflammation of the shoulder capsule, which is the connective tissue around the shoulder joint.

Question 15

Epicondylitis (example: tennis elbow)

Answer 15

Tendonitis affecting the elbow or knee Note: a condyle is a knuckle joint.

Question 16

Cervical spondylosis

Answer 16

Degenerative osteoarthritis of the joints between the centra of the spinal vertebrae in the neck. Note: the centra are the solid parts of a vertebra

Question 17

Tension neck syndrome

Answer 17

Symptoms include: pain, tenderness and stiffness of muscles, signs of hardened bands or nodularities, and muscle spasm.

Question 18

WRULD Risk factors

Answer 18

Repeating an action Uncomfortable working positions Using a lot of force Carrying out a task for a long period of time Poor working environment Underlying effects of the work and conditions Workers’ individual differences

Question 19

The key legal requirements are:

Answer 19

 The general requirements for risk assessment and management under the Management of Health and Safety at Work Regulations 1999, as amended.  The general requirements for workstation and seating design under Regulation 11 of the Workplace (Health, Safety and Welfare) Regulations 1992, as amended.

Question 20

Manual handling assessment chart (MAC) tool, factors to consider 8

Answer 20

Load weight/frequencyHand distancefrom lower backVertical liftregionTrunk twisting/sidewaysbendingPosturalconstraintsGrip on the loadFloor surfaceOtherenvironmentalfactors

Question 21

Assessment of Repetitive Tasks (ART) tool, factors to consider 4

Answer 21

Stage A: Frequency and repetition of movements Stage B: Force Stage C: Awkward postures Stage D: Additional factors.

Question 22

Structure of the spine

Answer 22

(Neck) Cervical area C1 – C7(Chest) Thoracic area T1 – T12(Lower back) Lumbar area L1 – L5(Tailbone) Sacrum and coccyx

Question 23

The main functions of the spine are to: 3

Answer 23

 Provide safe passage for the central nervous system, to and from the brain to the rest of the body.  Provide the human with a range of movement and a deal of flexibility that a single fused bone would not.  Act as a weight bearing structure for key body aspects, such as the rib cage, muscles, tendons, and nerves.

Question 24

Intervertebral discs have three main functions:

Answer 24

 To act as a shock absorber, cushioning the vertebrae from vibration and compression forces, and spreading the load out across the surface of the bone.  Forming a strong link between the vertebrae (hence the term’ slipped disc’ is rather a misleading one).  Allowing movement between the bones, while at the same time controlling the extent of the movement (in association with ligaments).

Question 25

A manual handling operation is defined as:

Answer 25

… any transporting or supporting of a load (including the lifting, putting down, pushing, pulling, carrying or moving thereof) by hand or by bodily force.

Question 26

The regulations require the employer (so far as is reasonably practicable) to: 4

Answer 26

 Avoid the need for manual handling jobs which involve a risk of injury.  Assess the risks arising from manual handling tasks that cannot be avoided.  Reduce the risk of injury (preferably by automation or mechanisation).  Inform employees of: - the weight of each load - the heaviest side of any load, whose centre of gravity is off centre.

Question 27

Training should cover: 4

Answer 27

 Manual handling risk factors and how injuries can occur.  How to carry out safe manual handling including good handling technique.  Appropriate systems of work for the individual’s tasks and environment.  The use of mechanical aids.

Question 28

Safe lifting technique There is no single correct way to lift. The following process illustrates some important points which are relevant to a two-handed symmetrical lift, (i.e. a lift using both hands in front of and close to the body). It is based on research by the Institute of Occupational Medicine (IOM), for the HSE.

Answer 28

(1) Plan the lift/handling activity. (2) Keep the load close to the waist. (3) Adopt a stable position. (4) Ensure a good hold on the load. (5) Moderate flexion. (6) Don’t flex the back any further while lifting. (7) Avoid twisting the back or leaning sideways especially while the back is bent. (8) Keep the head up when handling. (9) Move smoothly. (10) Don’t lift or handle more than can be easily managed. (11) Put down and then adjust.

Question 29

The main types of harm caused by computer use are: 3

Answer 29

 musculoskeletal disorders (MSD) including back pain and work related upper limb disorders (WRULDS)  visual fatigue  mental stress.

Question 30

The Display Screen Equipment Regulations 1992 seek to protect workers from the risks of DSE work by requiring employers to: 5

Answer 30

 Analyse workstations to assess and reduce risks.  Ensure workstations meet specified minimum requirements.  Plan work activities so that they include breaks or changes of activity.  Provide eye and eyesight tests on request, and special spectacles if needed.  Provide information and training.

Question 31

The combination of factors which give rise to risks makes it impossible to lay down hard-and-fast rules about who should be classified as a user or operator. Consideration should be given to: 7

Answer 31

 continuous spells of an hour more  daily use of DSE  fast information transfer  high attention and concentration  high dependency on the DSE  little choice whether or not to use the DSE  special training or skills.

Question 32

Workstation minimum requirements 11

Answer 32

(1) Adequate lighting (2) Adequate contrast, no glare or distracting reflections (3) Distracting noise minimised (4) Leg room and clearances to allow postural changes (5) Window covering if needed to minimise glare (6) Software: appropriate to task, adapted to user, providing feedback on system status, no undisclosed monitoring (7) Screen: stable image, adjustable, readable, glare/reflection-free (8) Keyboard: usable, adjustable, detachable, legible (9) Work surface: with space for flexible arrangement of equipment and documents, glare-free (10) Chair: stable and adjustable (11) Footrest if user needs one.

Question 33

Information and training The employer should provide users with adequate information on: 5

Answer 33

 health and safety relating to their workstations  risk assessment and steps taken to reduce risks  breaks and changes of activity  eye and eyesight tests  requirements for training.