Chapter 9: Joints

Topics Covered

• Rheumatoid arthritis
• Slipped discs
• Labral tears
• Unhappy triad
• Classification of joints
• Types of arthritis

Classification of Joints

Based on Structure

• Fibrous Joints (Synarthrosis): Dense connective tissue; largely immovable.
• Cartilaginous Joints (Amphiarthroses): Connected by cartilage, slightly movable.
• Synovial Joints (Diarthroses): Connected by synovial cavity, freely movable.

Based on Function

• Synarthroses: Immovable joints (e.g., sutures of the skull).
• Amphiarthroses: Slightly movable joints (e.g., vertebral column).
• Diarthroses: Freely movable joints (e.g., most synovial joints).

Synovial Joints

• Components: Articular cartilage, synovial fluid, meniscus, fat pads, ligaments, tendons, and bursae.
• Function: Provide movement and stability.
• Stability vs. Mobility: More stable joints have less motion; more mobile joints are prone to dislocation.

Types of Motion

• Gliding Motion: Bones slide past each other.
• Angular Motion: Change in angle between bones.
  • Flexion and Extension: Bending and straightening.
  • Abduction and Adduction: Movement away and towards midline.
• Rotational Motion: Around a central axis.
• Special Motions: Supination and pronation (e.g., hand rotation via elbow).

Specific Joints

Intervertebral Joints

• Structure: Cartilaginous with ligaments.
• Slipped Disc: Nucleus pulposus bulges/ruptures through annulus fibrosus, affecting nerves/spinal cord.

Shoulder Joint (Glenohumeral)

• Structure: Ball and socket, wide range of motion.
• Risks: Labral tears can lead to dislocations.

Hip Joint (Coxal)

• Structure: Ball and socket, more stable than the shoulder.

Knee Joint

• Structure: Hinge joint, multiple ligaments, meniscus.
• Common Injuries: Anterior cruciate ligament, medial collateral ligament, lateral meniscus.

Temporomandibular Joint

• Stress and Damage: Excessive force can cause difficulties.

Hypermobility

• Double-jointed: More mobile joints, risk of damage, leading to osteoarthritis.

Arthritis

Osteoarthritis

• Cause: Wear and tear of cartilage over time.

Rheumatoid Arthritis

• Cause: Autoimmune, inflammation of synovial cavity.
• Diagnosis: Blood tests for inflammation markers.

Gouty Arthritis

• Cause: Metabolic disorder, crystals in synovial fluid.

Treatment

• Rheumatoid Arthritis: Anti-inflammatory drugs, immune-targeting drugs.

Conclusion

• Differentiation between diseases:
  • Osteoarthritis: Joint disease.
  • Osteoporosis: Bone disease.