Mechanics of Musculoskeletal System

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IE 552 Mechanics of Musculoskeletal System Dr.
Andris Freivalds Class 26
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Musculoskeletal Disorders (WRMSDs) (cumulative
trauma-, repetitive motion- disorders)

• Tendon disorders
• Tendonitis microtears, fraying
• Tenosynovitis swelling, narrowing of sheath

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Musculoskeletal Disorders (WRMSDs) (cumulative
trauma-, repetitive motion- disorders)

• Muscle disorders
• Acute strain myalgia
• Chronic strain myositis, myofascial pain
• Cramping focal distonia

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Musculoskeletal Disorders (WRMSDs)

• Nerve related disorders
• Entrapment between tissues
• Vascular disorders
• Ischemia of blood from vibration and/or cold

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Musculoskeletal Disorders (WRMSDs)

• Bursa disorders
• Bursitis sac with synovial fluid around joint
• Bone and cartilage disorders
• Osteoarthritis degeneration of joint cartilage
• Rheumatoid arthrits inflammation, build-up
• Gout - metabolic disorder, uric crystals in joint

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Musculoskeletal disorders which may be work
related (WRMSDs)
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Musculoskeletal disorders which may be work
related (WRMSDs)
Raynauds syndrome (V)
white finger(V)
radiculopathy (cervical syndrome) (N)
ganglionic cysts (T)
tension neck syndrome (M)
Guyon canal syndrome (N)
extensor tenosynovitis(T)
extensor tendinitis (T)
bursitis(J)
shoulder tendinitis (rotator cuff) (T)
Disorders (by type) T Tendon M Muscle N
Nerve V Vascular J Joint
BACK
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Carpal Tunnel and Thoracic Outlet Syndromes
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Resisted ROM ManeuversFlexion/Extension
Radial/Ulnar Deviation
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Diagnostic Tests
Finkelsteins Test Form fist with thumb enclosed
for 1 min.
Phalens Test Press flexed hands together for 1
min. Reverse Phalens Test Press extended hands
together for 1 min.
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Median, Radial, Ulnar Nerve Innervation Patterns
Tinels Test 2-Pt Discrimination Test Nerve
Conduction Test
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Epidemiology and WRMSDs

• Epidemiology study of distribution and control
  of diseases (public health)
• Identify and control of occupational stressors
  leading to WRMSDs
• Epidemiological techniques
• Manipulation of risk factors (exposure to risk)
• Randomization of subjects (assign them to various
  exposures)
• Intervention vs. observation

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Types of Epidemiological Studies
Type M R Unit Rigor Time Cost Concern ( vs -)
Clinical trials Experimental Y Y indiv weeks rigor vs cost,ethics
Community studies -quasi Y N pop months educ vs time, loss
Observation Non-exp N N indiv - depend see next
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Clinical Trials (Intervention)
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Community Trials (Intervention)
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Types of Obervational Studies
Type Rigor Time Cost Best Worst
Cohort Prospective long Clear, accurate Time, lose subjects
Case-control Retrospective 0 short Rare, small Selection bias
Cross-sectional - one obs - Quick, simple Snapshot, validity
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2 x 2 Contingency Table
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Cross-Section Study
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Contingency Table in a Cross-Sectional Study
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Retrospective Case-Control Study
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Contingency Table in a Case-Control Study
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Prospective Cohort Study
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Contingency Table in a Cohort Study