Anatomy and Biomechanics for Occupational Ergonomics

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Anatomy and Biomechanicsfor Occupational
Ergonomics

• IE 665

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Anatomical sites important for occupational
ergonomics

• Spine Occupational back pain
• Upper extremity CTDs in neck, shoulder and
  wrist
• Lower extremity pain foot and ankle

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Spine
Lordosis
Kyphosis

• Spinal curves
• Spinal shrinkage and
• Disc nutrition
• No pain sensation in load bearing bodies
• Micro-trauma of discs and cumulative load
• Disc degeneration

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Upper Extremity
Clavicle
Scapula
Humerus
Radius
Ulna
Carpals
Phalanges
Metacarpals
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Shoulder
Rotor cuff syndrome Tendonitis Bursitis Frozen
shoulder
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Carpal tunnel
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Joints
Ball and socket Shoulder, Hip Hinge Elbow,
Knee Pivot Between ulna and radius Fixed - Skull
Bursa A small, flat, fluid filled sack protects
ligaments from friction with bones Bursitis
inflamed bursa
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Biomechanics of posture
All body segment is subjected to gravitational
force When CG of a body segment is vertically
aligned with a joint joint tension or
compression weight of the body segment Due to
postural changes, CG of the body segment moves
away from the joints vertical alignment. This
creates a moment around the joint. M
ForceMoment arm (perpendicular distance from the
joint axis). This moment due to gravitational
force is countered internally by the muscles to
maintain the posture. To maintain the posture MR
MM MR Moment due to external forces MM
Moment due to internal muscle forces
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Biomechanics of elbow joint
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Biomechanics of head and neck
MR
MM
Head-neck 7 of BW 0.07150 10.5 lb Ratio of
moment arm 21 Muscle force 21 lb Joint
compressive force 31.5 lb
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Biomechanics of spine
Body weight 200 lb R Upper body wt
2000.65 130 lb Fback muscle tension at (L5/S1)
? Spine compression at (L5/S1) ? For straight
back R2F2 or, F 130 lb Total L5/S1
compression RF 260 lb For bent
back R8F2, F 1308/2 520 lb Total L5/S1
compression RF 520130 650 lb
L5/S1 joint compression increased by 2.5 times
and back muscle tension increased by 4 times from
leaning forward
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Biomechanics of material handling