L4.6.3: Structural Joint Classifications

• Structural Joint Classifications

  • Fibrous Joints
  • Cartilaginous Joints
  • Synovial Joints
• Fibrous Joints

  ○ Generally immovable

  ○ Bones are united by fibrous tissues.

  ■ Collagens as the Main Component.

  ○ An example is the fontanelle in a fetal skull.
• Types of Fibrous Joints

  ● Sutures

  ● Syndesmoses

  ● Gomphoses
• Sutures

  Immobile.
• Syndesmoses

  More movement than sutures but still immobile; often in the distal ends of the tibia and fibula.
• Gomphoses

  Immobile; where teeth meet the face.
• Cartilaginous Joints

  ○ Immovable or slightly movable

  ○ Bones are connected by fibrocartilage.

  ○ Ex: Intervertebral disc.
• Types of Cartilaginous Joints

  ● Synchondrosis

  ● Symphysis
• Synchondrosis

  Immobile

  On epiphyseal plates of long bones
• Symphysis

  Slightly Movable

  Pubic Symphysis & Intervertebral Joints
• Synovial Joints

  ○ Freely movable

  ○ On articulating bones separated by a joint cavity.

  ○ Has synovial fluid.

  ○ Four Distinguishing Features:

  a] Articular Cartilage

  b. Articular Capsule

  c. Joint Cavity (+ Fluid)

  d. Reinforcing Ligaments
• STRUCTURE OF SYNOVIAL JOINTS

  ● Bursae: flattened fibrous sacs. Lined with synovial membranes and filled with synovial fluid.

  ○ Not actually part of the joint.

  ○ To reduce friction.

  ● Tendon Sheath: Elongated bursa that is wrapped around a tendon.
• Specific Types of Synovial Joints

  Types Characteristics

  ● Plane Joint In between vertebral bone

  ● Hinge Joint Between the Humerus and Ulna

  ● Pivot Joint Between radius and Ulna
• Specific Types of Synovial Joints based on Shape

  Types Characteristics

  ● Condylar Joint Base of the skull and vertebral bone

  ● Saddle Joint Between carpal and metacarpal

  ● Ball-and-socket Between scapula and humerus
• Synovial Membrane

  ○ These membranes line the fibrous capsules surrounding joints, where they provide a smooth surface and secrete a lubricating fluid.