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.