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Understanding Joints and Their Types

Dec 11, 2024

Lecture Notes: Joints

Introduction to Joints

  • Definition: A joint, or an articulation, is a place where bones connect or a bone connects with cartilage.
  • Common Examples: Shoulder joint, knee joint, hip joint.
  • Other Examples: Joints of the skull, teeth in the jaw, ribs to the sternum.

Classification of Joints

  • Basis of Classification:
    • Size of the space at the joint.
    • Freedom of movement.
  • Terms to Know:
    • Synarthrotic Joint: An immobile joint.
    • Amphiarthrotic Joint: A joint that can partially move.
    • Diarthrotic Joint: A freely movable joint.

Types of Joints

  • Fibrous Joints:

    • No joint cavity.
    • Bones connected with dense regular connective tissue.
    • Examples:
      • Suture Joints: Found in the skull, e.g., sagittal suture.
      • Gomphoses: Teeth secured in the jaw.
      • Syndesmoses: Connective tissue between the radius and ulna or tibia and fibula.
  • Cartilaginous Joints:

    • No joint cavity.
    • Cartilage connects bones.
    • Examples:
      • Synchondroses: Contains cartilage within bone, e.g., epiphyseal plate (growth plate).
      • Symphyses: Pubic symphysis, cartilage between hip bones.
  • Synovial Joints:

    • Contains a joint cavity.
    • Joint cavity has a synovial membrane releasing synovial fluid.

Subcategories within Joint Types

  • Fibrous Joints:

    • Suture Joints: Immobile, e.g., skull sutures.
    • Gomphoses: Immobile, e.g., teeth in the jaw.
    • Syndesmoses: Partly movable, e.g., joints holding radius and ulna.
  • Cartilaginous Joints:

    • Synchondroses: Immobile, e.g., epiphyseal plates.
    • Symphyses: Partly movable, e.g., pubic symphysis.
  • Synovial Joints:

    • Freely movable, e.g., found in various body parts with varying degrees of motion.

Further Exploration

  • Future Discussion: A deeper dive into synovial joints, their locations, and movement ranges.