Cartilage, joints, range of motion

Cartilage, Ligaments, and Tendons

  • Types of Cartilage

    • Hyaline Cartilage:

      • Composition: A mix of collagen, proteoglycans, and water.

      • Appearance: Glassy and translucent with a smooth surface.

      • Function: Allows for smooth bone movement (found in the rib cage and joints).

    • Fibrocartilage:

      • Composition: Contains more collagen with thicker strands.

      • Properties: Very tough and highly compressible.

      • Location: Areas requiring high pressure resistance (e.g., vertebrae disks).

    • Elastic Cartilage:

      • Composition: Contains collagen, proteoglycans, and elastic fibers.

      • Properties: Can return to its original shape after stretching.

      • Location: Areas needing both rigidity and elasticity (e.g., ears).

  • Connective Tissue Distinctions

    • Ligaments: Connect bone to bone.

    • Tendons: Connect muscle to bone.

Joint Classifications and Movement

  • Fibrous Joints

    • Characteristics: No joint cavity; exhibit little to no movement (e.g., skull joints).

    • Structures:

      • Sutures: Seams.

      • Syndesmoses: Slightly moveable joints joined by ligaments.

      • Gomphoses: Pegs and sockets.

  • Cartilaginous Joints

    • Characteristics: Two bones held together by a pad of cartilage; exhibit little to no movement.

    • Structures:

      • Synchondroses: Joined by hyaline cartilage.

      • Symphyses: Joined by fibrocartilage.

  • Synovial Joints

    • Characteristics: Larger cavity containing synovial fluid; allow for significant movement.

    • Anatomy: Bones are covered in hyaline cartilage and the joint is encased in a capsule.

    • Types of Synovial Connections and Movements:

      • Plane: Flat shape; allows limited gliding movement.

      • Saddle: Shaped like two saddles at a 90-degree90\text{-degree} angle; moves like a "bucking bull."

      • Hinge: Allows for bending/folding movements.

      • Pivot: Allows rotational movement around a single axis.

      • Ball-and-socket: Allows full rotational/spherical movement.

      • Ellipsoid: A modified ball-and-socket allowing elliptical movement.

  • Categories of Movement

    • Gliding: Occurs in plane joints; involves only slight movement.

    • Angular Movements:

      • Flexion/Extension: Decreases or increases the space between bones (brings closer or lengthens).

      • Abduction/Adduction: Movement away from or toward the midline.

    • Circular Movements:

      • Rotation: Turning a structure around its long axis.

      • Pronation/Supination: Arm movements (palm down for prone, palm up for supine).

      • Circumduction: Full rotational motion specific to ball-and-socket joints.

    • Special Movements:

      • Elevation/Depression: Moving a structure superiorly or inferiorly.

      • Protraction/Retraction: Moving a structure anteriorly or posteriorly.

      • Excursion: Moving a structure medially or laterally.

      • Opposition: The specific movement allowing the thumb and a finger to touch.

  • Range of Motion (ROM)

    • Passive ROM: Motion achieved via external application of force.

    • Active ROM: Motion occurring through an individual's own muscular effort.

  • Range of Motion Injuries

    • Dislocation: Occurs when bones are moved out of their proper alignment.

    • Sprain: Occurs when ligaments are damaged.