Musculoskeletal System Notes

Musculoskeletal System

Introduction

• This chapter covers the musculoskeletal system.

Anatomy and Physiology

Bone

• Hard tissue making up most of the skeletal system.

• Functions:

  • Support.

  • Protection.

  • Movement.

  • Storage of calcium and other ions.

  • Manufacture of blood cells.

Cartilage

• Specialized fibrous connective tissue.

• Provides firm but flexible support for the embryonic skeleton and parts of the adult skeleton.

• Cartilage cells are called chondrocytes.

Ligaments

• Strong, fibrous bands of connective tissue connecting bones and cartilage and supporting muscles.

• Yellow ligaments:

  • Located in the vertebral column.

  • Elastic, allowing for stretching.

• White ligaments:

  • Found in the knee.

  • Do not stretch but provide stability.

Tendons

• Composed of very strong and dense fibrous connective tissue.

• Shaped like heavy cords.

• Anchor muscles firmly to bones.

Joint Structure and Function

• Connective tissue disorders manifest as joint disorders because joint mobility depends on functional connective tissue.

• Joint: site where two or more bones join, permitting motion and flexibility.

• Classification:

  • Synarthroses (fixed joints).

  • Amphiarthroses (slightly movable joints).

  • Diarthroses (freely movable joints).

  • Encased in a fibrous capsule made of strong cartilage and lined with synovial membrane.

Synarthroses

• Fibrous Joints

  • Examples:

    • Sutures between skull bones (e.g., Parietal bone, Coronal suture, Frontal bone)

    • Interosseous ligament between tibia and fibula, ulna and radius.

    • Periodontal membrane securing tooth root in socket

Amphiarthroses

• Cartilaginous Joints

  • Examples:

    • Costosternal synchondrosis between ribs and sternum via costal cartilage

    • Epiphyseal plate (hyaline cartilage) in long bones

    • Vertebral discs (fibrocartilage)

    • Symphysis pubis

Diarthroses

• Synovial Joints

Skeletal Muscle

• Primary function of skeletal (voluntary, striated) muscle tissue:

  • Contract and cause movement.

  • Keep joints stable by preventing excess movement, maintaining skeletal stability, and preventing structural damage or deformation.

  • Protect internal organs (abdominal and pelvic) by acting as an external barrier or shield to external trauma and by supporting organ weight.

Age-Related Changes

• Loss of bone mass and bone strength.

• Osteoporosis common in women but also affects men, increasing fracture risk.

• Cartilage gradually loses elasticity, becomes soft and frayed.

• Water content decreases; cartilage may ulcerate, leaving bony joint surfaces unprotected, promoting osteophyte (bony spurs) growth, results in pain and limited mobility.

• Decline in muscle mass, especially in the extremities.

Assessment

Health History

• Reason for seeking care.

• Present health.

• Past health history (including accidents and injuries).

• Family history.

• Review of systems.

• Functional assessment.

Physical Assessment

• Compare bilaterally, starting with the unaffected side.

• Assess:

  • Inspection: Skin color, lesions/drainage.

  • Palpation: Tenderness, warmth, capillary refill, pulses.

  • Range of motion (listen while doing it).

Diagnostic Tests and Procedures

Laboratory Studies

• Blood studies:

  • Complete blood cell count.

  • Erythrocyte sedimentation rate (ESR).

  • C-reactive protein (CRP).

  • Rheumatoid factor (RF).

  • Creatinine.

  • Antinuclear antibody (ANA) tests.

• Urine studies:

  • Creatinine and uric acid levels.

• Examination of joint fluid.

Radiologic Imaging Studies

• Radiography.

• Arthrography.

• Nuclear scintigraphy.

• MRI.

• Discography.

• Tomography.

• CT.

Vascular Studies

• Pulse volume recording.

• Thermography.

• Doppler ultrasound.

Other

• Arthroscopy.

• Biopsy.

Common Therapeutic Measures

Physical and Occupational Therapy

• Helps preserve functional capability and minimize disability.

• Braces and splints support inflamed joints, protect from further injury, and relieve discomfort.

• Helps make adaptations in work and personal life to allow maximal function.

• Education and support.

Drug Therapy

• NSAIDs.

• Glucocorticoids (systemic and intraarticular).

• Disease-modifying antirheumatic drugs (DMARDs) I/II/III.

• Antigout/uricolytic medications.

• Bone resorption inhibitors.

Surgical Treatment