Overview of Joints

Definition

• Joints (Articulations): Sites in the skeleton where two or more bones meet.
• Composition: Not made of osseous tissue; consists of different tissue types.

Main Functions

1. Hold Bones Together:
   • Serve as the weakest component of the skeleton.
   • Most likely to get damaged.
2. Facilitate Mobility:
   • Allow movement of the skeleton.

Classification of Joints

Based on Function

• Synarthrosis:
  • Root Word: 'Arthro' means joint.
  • Syn (Together): Immovable joints where bones are held together.
• Amphiarthrosis:
  • Amphi (Both Sides): Joints with some movement capability.
• Diarthrosis:
  • Di (Through or Apart): Freely movable joints where bones can move past each other.

Based on Structure

• Fibrous Joints:
  • Lack a joint cavity.
  • Joined by fibrous tissue (dense connective tissue).
  • Tend to be immovable.
• Cartilaginous Joints:
  • Lack a joint cavity.
  • Dominated by cartilage.
  • Limited movement.
• Synovial Joints:
  • Have a joint cavity.
  • More complicated structure; will be covered in detail in another session.

Location and Mobility

• Fibrous Joints:
  • Primarily found in the axial skeleton.
  • Generally immovable.
• Cartilaginous Joints:
  • Found in the axial skeleton with limited mobility.
• Synovial Joints:
  • Found in upper and lower limbs.
  • Freely movable, allowing extensive mobility.